How to find the magnitude of earthquakes roughly if we know the Richter scale magnitude of epicenter?

Your question cannot be answered with any accuracy because the result depends mainly on a key unknown parameter: hypocentral depth D.
To show this, let me use the empirical relationship known as the Lillie formula:

$$m = \log(A) - 2.48 + 2.76*log(d)$$

Where:

$m$ is the local magnitude (no units).

$A$ is the amplitude of the maximum ground displacement (in micrometers) of the P-wave, measured at 0.8 Hz.

$d$ is your epicentral distance in km for large distances (hundreds of km).

Note that for low values (when approaching the epicenter) the equation does not hold because the log tends to -inf. That's why these empirical formulas are only used  for long epicentral distances, not at local scale (and definitely not at the epicenter).

Following your example, if your earthquake is very shallow you would have a huge magnitude difference between your station at distance d and the epicenter, whereas if the hypocenter is 600 km deep, m will be very similar in both places.

So you need to know the depth of the earthquake to derive the magnitude in the epicenter.


Calculate the number of model grid cells covering a specific country

Here is a simple 'back of the napkin' idea for Python:

Get a shapefile of the borders and use Python to create a polygon of the borders.
Use mpl_toolkits to convert the climate model to X and Y coordinates
Check to see if the model grid points are within the Polygon


How many supercontinents have there been?

There's a fairly decent Wikipedia page about this: https://en.wikipedia.org/wiki/Supercontinent
In short, though, the question of "how many times has this happened?" is very difficult to answer because the further you go back in Earth's history, the less evidence is still left today from that time. Not everything can or will ever be reconstructed with certainty.


Why does the frost depth increase when the surface temperature warms up?

That's is due to the slow diffusion of heat into the ground. Unlike a liquid, pieces of soil can't move around, therefore, in the absence of liquid water, heat can only be transferred by conduction, a process that follows the diffusion equations and it is very slow.

This means that if there is a heat wave, or a cold snap, their effect will reach deep layers of the soil with a delay, the deeper the longer the delay and the more dampened the wave will arrive.

This figure shows a heat wave in the soil

(figure from Soil Temperature at ScienceDirect)

As you can see, the plot shows that there was a peak in temperature of about 27°C at the surface (0m) at time t=6h, but that peak in temperature slowly diffused downwards, such that at a depth of 0.2 m, the peak happened at time t=8h reaching only about 23°C, and at a depth of 0.4 m it arrived even later, at about t=18h and reached only 21°C.

In you case, what is happening that the cold snap is still "traveling" down the ground.

An alternative way to understand this, is that the cold snap cooled the ground so that a layer below the surface can be now at, let's say -5°C, and it is on top of a deeper layer at +1°C, where the water pipe is located. What that deeper layer feels is not what happens in the surface, that is nice and warm, it feels the temperature of the layer right on top of it, that is still very cold. So that deeper layer will cool down and eventually freeze. Freezing as well  the water line with it.

That said, and to address some great comments. The current freezing of underground water lines responds to a past forcing. Therefore, it have nothing to do with current weather and is not the thawing ground what pushes the frost down. It is just the normal curse of events in the propagation of a cold/hot wave down into the ground.


Mixing equation for confluence of two rivers

You have to use mass weighted averaging to calculate the final concentrations of elements. The equation for your situation would be:

$\sf\bar{q}\ =\ \dfrac{m_1.q_1\ +\ m_2.q_2}{m_1\ +\ m_2}\ =\ \dfrac{\rho_1.v_1.q_1\ +\ \rho_2.v_2.q_2}{\rho_1.v_1\ +\ \rho_2.v_2}$

where:

$\small\sf m$ is the mass flow rate
$\small\sf v$ is the volume flow rate
$\small\rho$ is the density of water
$\small\sf q$ is the quantity/concentration of the element

Every second, $\small\sf{7000\ L}$ of water flows from River 1 into River 3. Similarly, $\small\sf{11\ m^3}$ of water flows from River 2 into River 3. The combined inflow into River 3 is $\small\sf{18\ m^3}$ every second.

Assuming the density of water in both inflowing rivers is the same, volume of water can be used instead of mass; if not then the density of water for each river needs to be used.

Assuming the water density of both rivers is the same, convert all to units SI units and the average concentration of Mg in River 3 is,

$\sf{\dfrac{7(0.5) + 11(0.34)}{(7 + 11)}}$ = $\sf{0.402\ g/L\ Mg}$

I'll let you do the calculation for Ca.


To what accuracy and precision do we know the volume of the Earth?

One way to approach this is to treat the Earth as an oblate ellipsoid. This would mean the errors arise from the uncertainties in the Earth's equatorial radius and the flattening. From Groten, "Fundamental Parameters and Current (2004) Best Estimates of the Parameters of Common Relevance to Astronomy, Geodesy, and Geodynamics," Journal of Geodesy 77:10-11, 724-797 (2004), the Earth's equatorial radius in the mean tide system is 6378136.72±0.10 meters, and the inverse flattening is 1/f = 298.25231±0.00001. The uncertainty in volume due to the uncertainty in equatorial radius is about $3 V \frac{\Delta a}{a}$, where $V=\frac 4 3 \pi (1-f) a^3$, or about 51,000 cubic kilometers. The uncertainty in volume due to the uncertainty in inverse flattening is tiny in comparison, about $V \frac {\Delta 1/f} {1/f (1/f - 1)}$, or about 120 cubic kilometers.

That 51,000 cubic kilometer figure sounds like a lot, but it's not. It means the volume of the Earth can be expressed to seven places of precision.


What is sub-tropical wet climate, semi-arid climate and semi-tropical continental climate?

The sub-tropics are climatically very variable. Most of this zone is arid or semi-arid, but there are some wet areas. The wet areas also vary considerably. Some of them have quite cold winters where the temperature just manages to keep a few degrees above zero, others keep comfortably above zero.

Sub-tropical wet climates can be found at the northern extremity of the South China Sea in places like Hongkong and Hainan Island, both in southern China. Here you can find classical rainforest not much different from that which exists over most of S.E. Asia, so that would be sub-tropical wet climate.. The climate in elevated areas of tropical Africa and New Guinea also falls into some definitions of sub-tropical (definitions vary a little) and have a similar climate to S.W.China. Further away from the tropics you can still find wet areas, but as I say, the sub-tropics tend to be mostly arid or semi-arid.

Continental subtropics tend to be more arid and have colder winters, while small islands in subtropical areas have a marine climate and tend to be damper and have milder winters. The Canaries are an example. North Island, New Zealand, is subtropical and has a climate similar to the better areas of the Mediterranean. The Sahara desert is mostly subtropical and very arid, but the Atlas mountains in the north are damper. Mountains tend to attract rainfall.


Are Fluvial and River Terraces the same?

In English, the word fluvial comes from the Latin word for river.
Fluvial processes are processes associated with rivers or streams and the deposits and forms created by them.
River terraces and fluvial terraces are the same thing.


Quotient farthest mouths/nearest sources

Tbb is correct. The 'Congo and Nile' is by far the winner. Their mouths are 4600 km apart, whereas if you trek into the Rwenzori mountains, Western Uganda, there is s small highland swamp in a saddle point on the Congo-Uganda watershed. On either side there are several points where you can claim to be 'at the source', where you can stand with one foot in the Congo basin and the other foot in the Nile basin. The Indus and Brahmaputra are less than half this distance apart.

As for the other extreme, it's impossible to say. There are several rivers which end at more or less the same place. One then has to argue, 'Is one river a tributary of the other, or not?'


What does mean "background" in statistics or geostatistics?

Note: Since there is more than one use case of background in geostatistics, I will pick only one. If this is not the right background you are looking for, please edit and clarify your question.

Answer: A data point can be given by an absolut value A or a background value B plus a deviation D where B + D = A.

Example: If you are looking at a map showing the mean temperature of year X, you can look at the absolute field A or on its deviation D from the climatological year mean temperature of 1961-1990 B. Sometimes the latter tells you more, depending on what you are interested in. Additionally, analyses and statistical methods are often applied to the deviation field instead of the absolute field to identify patterns.


How to find the top level of the planetary boundary layer in WRF?

Well, the variable PBLH should tell you the PBL height. If you want the level that the PBL is, I suggest modifying the Registry.EM_COMMON file.
Perhaps I can refer you to WRF-Python to help you with your calculation. For example, wrf.interplevel might be the function to use to interpolate to the PBL height. If you interpolate to fractions of the PBL height, you could one of the integration methods to sum up the number of fractions of the PBL height and get the average concentration of $\ce{CO2}$ in the PBL (also, divide by the PBL height to actually get the average).


Can we predict which annular modes existed during the time of Pangaea?

Since you're asking about Pangaea time, i would assume you're talking about the Permian (from 299Ma to 252 Ma).

We have a good idea of what Permian paleogeography was, a fair idea of how Permian oceans circulated globally (see one of your previous questions), enough data to produce credible models on how was the climate at the time (see e. g. Gibbs et al. 2002), even some idea on what atmospheric circulation (see e. g. Tibor & Montanez 2002) was like during that Period. So in theory i don't see any major hurdles to model these kind of oscillations (keep in mind that i am not a climate model specialist).

Now in my opinion, the big issue would be the data to back the model on, and particularly the time resolution needed to study these kind of oscillations: ENSO, PDO, NAM, SAM etc are annual to decadal oscillations (1-10yr).
A resolution "commonly"-achieved so far in detecting climatic oscillations in the Permian fossil record is for cycles of ca. 20kyr (i. e. 20 000 years; Milankovitch precession cycle). The kind of sedimentation rates and sediment quality needed to be able to record annual layers are extremely rare for such older sediments.

With that in mind, it's not impossible to find such sediments, in fact Anderson (1982) detailed the 260kyr-long continuous, annual varved Castille and Bell Canyon Permian evaporitic Formations, but even in such a high-resolution formation the shorter-length oscillation detected was still at ca. 180yr so way above that of any of the annular modes you mentioned.

References:
Anderon, R. Y., 1982. A long geoclimatic record from the Permian. Journal of Geophysical Research : Oceans, 87: 7285-7294.
Gibbs, M. T., McAllister Rees, P., Kutzbach, J. E., Ziegler, A. M., Behling, P. J., Rowley, D. B., 2002. Simulations of Permian Climate and Comparisons
with Climate-Sensitive Sediments. Journal of Geology, 110: 33-55.
Tibor, N. J., Montanez, I. P., 2002. Shifts in late Paleozoic atmospheric circulation over western equatorial Pangea: Insights from pedogenic mineral $\delta^{18}O$ compositions. Geology, 30: 1127-1130.


What techniques are used to date asteroid impacts?

Several possible ways..

Stratigraphic (Local):

If the crater has been buried, just date the first rocks that are on top of the crater but not disturbed by it; this can be done using fossil-based dating if no good radiometric techniques are available.  This has the advantage of being unambiguous, but the problem could be, especially for land based craters, that there is a gap between crater formation and new sediment deposition.

Stratigraphic (Regional)

If you can find a layer of ejecta (famously the layer of Iridium-rich ejecta from the K-T impact) and relate it to your crater, then you can often date this very precisely, more so than the disturbed area around the crater itself.  This has the potential to be more accurate than any other method, but you have to be sure that the Iridium-rich layer you are dating actually corresponds to the crater.

Radiometric

A large impact will almost certainly melt some rock locally at the site of impact, resetting any radiometric 'clocks' in that rock. If you can locate this impact melt, then there are a variety of radiometric techniques that you can apply to it, depending on the mineralogy. Potassium-Argon would be an example.


Is it possible to prevent high magnitude earthquakes by induced earthquakes?

The idea of trying to limit energy released by earthquakes and the damage that may result via the use of controlled smaller blast induced quakes is an interesting idea.

One of the problems with this is that we don't know enough about the snags along faults that cause stresses to accumulate during the normal movements along a fault. We also don't know enough about fault surfaces (shapes, undulations and friction factors) of individual fault surfaces. The other thing we don't know is where the snags are located on fault surfaces: along and down the fault surface.

The strength of snags is one factor which determines how much energy accumulates and is eventually released suddenly when the snag fails.

The other factor is the type of movement at the fault zone. Do the fault surfaces slide past one another laterally, does one sub-duct beneath the other, or are they spreading apart.

With some faults, wedge failures may produce large blocks that act a snags. Other snags can be very hard, strong protrusions of rock firmly cemented in the fault surface. Corrugations can also act as snags.

Another possible mechanism by which quakes can happen, particularly in the subduction zone is that part of the fault surface that is riding over a subduction zone might hang with no support, due to undulations or point support. If the overhanging rock is not strong enough it can fail and drop. The impact of the dropping block then causes an earthquake.

The ways in which earthquakes occur are varied and sometimes complex.


What would the average temperature be if there were no greenhouse effect from water vapor?

As was pointed out in the question comments, there is no way to know what Earth's average temperature would do without water vapor in the atmosphere.  However, we can estimate the effects of the water, and remove them.  What follows is a rough approximation.

If there were no greenhouse effect, the average temperature of Earth would be about 0F (-18C) instead of 59F (15C). (https://www.giss.nasa.gov/research/briefs/ma_01/)

Water vapor roughly doubles the warming caused by carbon dioxide. (https://www.nasa.gov/topics/earth/features/vapor_warming.html)

Therefore I estimate that without water vapor, the average temperature would be about 30F (-1C).


What would be the first thing which will render the Earth uninhabitable?

I'll try to put time scales on each of these events.

The Sun as a red giant - 5 to 6 billion years$^1$

The Sun is currently on the main sequence, which means that it's a "full grown" star - think of it as being middle-aged. It's been on the main sequence for around 4 to 5 billion years, and in 5 to 6 billion years, it will leave the main sequence.

Most yellow (i.e. spectral class G-ish) stars spend about 10 billion years on the main sequence. Then, they swell up as red giants. The Sun is just over halfway through the main sequence, so it has about 5 to 6 billion years left. After 5.4 billion years, it will grow. Here's an image showing how its radius (and other factors) will increase:

The Sun won't swallow the inner planets up right away - see how it takes a while for it to grow - but it will happen eventually. It will take another billion years to reach a radius 200 times that of its current size. It will enter the AGB phase, where it will finally grow enough to swallow the inner planets. It's uncertain as to whether or not Earth will be destroyed, but it will be heated up so much that liquid water will disappear and the planet will be uninhabitable.

NASA has an article on a Sun-like star swallowing up one of its inner planets, just as the Sun may do. The original paper can be found here.
Supernova/nova - Never

There are two types of supernovae: Type II and Type I. Type II supernovae are characterized by hydrogen; Type I supernovae have no hydrogen. You've probably heard of Type II supernovae when you learned about supernovae, and they're the more well-known. They're the result of the collapse of the core of a massive star. However, the progenitor, has t be much larger than the Sun - usually at least 8 solar masses.

Type I supernovae have no hydrogen. There are two main classes: Type Ia and Type Ib/c. The first category are the result of white dwarfs accreting mass from a companion star. The Sun has no binary companion, so even though it will become a white dwarf, it will never undergo this kind of supernova. Type Ib/c also result from core collapse, just like Type II. However, their progenitors are unstable, violent stars, typically Wolf-Rayet stars. Our Sun will fortunately never become one of those!

A nova is small compared to a supernova. It, like Type Ia supernovae, may be the result of a white dwarf accreting matter from a companion. Once again, though, the Sun has no companion star to accrete matter from.
Magnetosphere loss - Never

The Earth's magnetic field is very important, because it shields us from the solar wind. Without it, life on Earth probably couldn't exist! Its disappearance would not be good for us.

Fortunately, it doesn't appear that that will ever happen.

The Earth's magnetic field is believed to be caused by the movement of fluids in Earth's core. Wikipedia lists three conditions necessary for the existence of the magnetic field:

  An electrically conductive fluid medium
  Kinetic energy provided by planetary rotation
  An internal energy source to drive convective motions within the fluid.

The fluid in the Earth's core will never go away, and so long as the planet keeps rotating, that kinetic energy will always be there. So will the Coriolis effect, which also helps circulate the fluid and control the magnetic field. The source of the energy that keeps the material hot is due in part to tidal forces between the Earth and other bodies, such as the Moon and the Sun.
Collision - Not for a long time

The Earth has had one major collision throughout its life, and that spawned the moon. This idea is known as the giant impact hypothesis. When the solar system - and Earth - was young, the Sun had a disk of small pre-planetary bodies, known as protoplanets. There were more protoplanets than there are planets today, because many collided to form the planets.

The hypothesized protoplanet, named Theia, is generally described as Mars-like. It didn't hit the Earth head-on, but rather hit it an a 45 degree angle. The result was that Theia was destroyed and some of Earth was ejected. Much of this material came back to Earth, but some stayed and formed the Moon.

There aren't any more protoplanets, but there are still some large asteroids. The biggest is Ceres, which is tiny compared to Theia. Here's a picture of Earth, the Moon and Ceres (bottom left):

We're not likely to see another giant impact again. The other planets all have stable orbits, and the Moon's actually receding from Earth due to tidal forces. Sure, asteroid impacts are a possibility, but the possibility of a doomsday asteroid is tiny. Even a body like the one that killed the dinosaurs wouldn't extinguish all life. The Jet Propulsion Laboratory has information on the likelihood of such a catastrophic event (not a high one!).
Gamma-ray burst - Probably never

I wrote an answer on Astronomy about this a while ago. If I may, I'll quote from that answer:

  Okay, back to the topic at hand. Wikipedia, of course, has a short tidbit on the frequency of gamma-ray bursts effecting Earth:

    Estimating the exact rate at which GRBs occur is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for long-duration GRBs) is about one burst every 100,000 to 1,000,000 years. Only a small percentage of these would be beamed towards Earth. Estimates of rate of occurrence of short-duration GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.

  'A small percentage' isn't too specific. The BBC article that is cited in this passage says the following:

    Observations of deep space suggest that gamma ray-bursts are rare. They are thought to happen at the most every 10,000 years per galaxy, and at the least every million years per galaxy.

  However, the 'small percentage' is never elaborated on.

$^1$An estimate

Earth will become uninhabitable long before the Sun swallows it up - if it is swallowed up - because its surface temperature will be so high life cannot exist. I wanted to see if I could figure out when that would be.

You can approximate the temperature of a planet by using the formula for effective temperature:
$$T=\left(\frac{L(1-a)}{16 \pi \sigma D^2} \right)^{\frac{1}{4}}$$
where $L$ is the star's luminosity, $a$ is the planet's albedo $\sigma$ is the Stefan-Boltzmann constant, and $D$ is the distance from the planet to the star.

The current mean temperature of Earth is about 15 degrees Celsius (288 K). However, this is the average surface temperature. Fortunately, the equation given for surface temperature is also of the form
$$T=C L^{\frac{1}{4}}$$
where $C$ is a constant. This means that
$$T^4 \propto L$$
The boiling point of water is 373 K, which is 1.295 times the current surface temperature. If we plug this in,
$$L= \propto (1.295)^{\frac{1}{4}} \approx. 2.81$$
So the luminosity of the Sun would have to be about 2.81 times the current luminosity of the Sun. This value isn't on the graph I gave at the top, though it appears to be about 7 billion years from now. Wikipedia gives this point as only 1 billion years from now, because of a greenhouse effect. So we've only got 1 billion years to live!


Did a crater cause the break up of Gondwanaland & separate Australia from Antarctica

To clarify:

Your question is valid, although if you are referring to Dr. von Frese's words as paraphrased in this article, you may be conflating a potential "breakup initiation" with something like the "creation of a geologically weak area prone to rifting under extensional stress". I believe the thought that such a crater could have caused the beginnings of the rifting process was not entertained by Dr. von Frese himself. Instead, according to the article you cited, von Frese explains that Antarctica and Australia began rifting roughly 100 million years ago, and rifting just so happened to occur very near the proposed impact site. From the article:

  The rift cuts directly through the crater, so the impact may have helped the rift to form, von Frese said.

It's a little unclear, but I think von Frese is making the connection here that a crater of that size could have potentially created weak planes in the crust near the impact site, which would have directed extensional stress relief to a localized region, thus centralizing a rift locally. This is a plausible conclusion, but as far as I can tell, no evidence other than proximity has been found to support it.

To answer:

The existence of the crater has not been verified, and more recent research casts doubt about the validity of claims that the Wilkes Land structure is in fact an impact crater.

Furthermore, the date for the final breakup of Gondwana is fairly well established, and enough research has been conducted to construct extensive historical summaries of the time period. As stated by von Frese, most geologists put the start of rifting in the Wilkes Land region at about 100 million years ago, in the Cretaceous period.

If we allow the assumption that the crater is indeed caused by a bolide impact, most studies suggest an impact date near the time of the Permian-Triassic boundary, a period known for its multiple mass-extinctions, around 250 million years ago. That would leave roughly 70 million years between impact and Gondwana's very earliest rifting (~180 mya), which is a relatively significant amount of time by tectonic standards. As stated in the above reference, the current most accepted "method" of Gondwanan rifting is via mantle plumes forcing the continents apart from below.

Based solely on these two pieces of evidence, I'd feel relatively confident in putting forth that the breakup of Gondwana was not caused by a bolide impact. If the Wilkes Land structure is ever drilled, and shocked quartz or other impact indicators are found in the samples, I would want to revisit this answer to investigate what I'll call "Dr. von Frese's Planes of Weakness" claim more closely.


Books for learning applied seismic geophysics

Here's a list of resources I've compiled before. Between them, maybe you'll find what you're after:

Some important geophysics papers and books: Must-read geophysics.
Six books about seismic interpretation — most of these include something about seismic attributes.
Six books about seismic analysis — more quantitative, and usually with lots of theory. I especially recommend Simm & Bacon.

I recommend learning what you can about rocks — their genesis, their properties, and especially their acoustic and elastic behaviour. If possible, go and see outcrops or at least cores. If possible, take classes in sedimentology, petrology, or even reservoir engineering.

You need to read about integrated interpretation; here are some other phrases to look for: well ties, phase estimation, spectral decomposition, seismic inversion, pre-stack seismic analysis, AVO. I recommend subscribing to CSEG Recorder, EAGE First Break and SEG Leading Edge.

Good luck in your quest!


What is meant by controlling and reacting factor?

A controlling factor is a factor that acts as a cause for others.  A reactive factor is rather the consequence: that which reacts to the controlling factor.

For example, the Sun is certainly a controlling factor.  Nothing we do influences what happens on the Sun, but what happens on the Sun certainly influences us very strongly.  Fortunately, its total power output is quite stable so as far as climate is concerned, we don't need to worry about it too much as far as the next couple of million years are concerned (although eventually, in hundreds of millions to billions of years, increasing power from the Sun will render the Earth uninhabitable).

CO₂ is both a controlling and a reactive factor.  We add CO₂ to the atmosphere, so the CO₂ concentration reacts to our emissions (reactive factor).  But CO₂ levels are also a cause.  If you were to make a simple climate model, you would put in the CO₂ concentration as a fixed value or perhaps an increasing value as a function of time: in such a model, it would be a boundary condition.  If you instead made a model of a single factory or car and modelled how changes in the fuel cycle would affect CO₂ emissions, then those would instead be a reactive factor.  It all depends on the context.

For H₂O, however, it makes no sense to put in a fixed version as a boundary condition.  Its concentration varies rapidly on short timescales: today may be dry and tomorrow a wet airmass may get in.  Of course, physically, H₂O causes even more of the greenhouse effect than CO₂, but the increase of H₂O is not what is causing anthropogenic climate change; if anything, an increase in H₂O is one of the effects.

So, think of it as a system: you add CO₂ (cause), many things happen, including an increase in H₂O in some places (effect).  The cause is the controlling factor.  The effect is the reactive factor, even though physically, both CO₂ and H₂O are strongly contributing greenhouse gases.


Comparing 2D fields - how do you quantify similarity?

Model data seta can vary in several ways from a reference data set. Taylor diagrams visually compare multiple datasets output to a reference dataset (e.g., model experiments to observations). This is done by exploiting the geometric relationship between centered RMS, correlation, and standard deviation when computing differences between datasets. Several software packages exist to produce Taylor diagrams.
wiki: https://en.wikipedia.org/wiki/Taylor_diagram
publication: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2000JD900719
python, e.g.: https://pypi.org/project/SkillMetrics/


At the coast the horizon facing the ocean is unobstructed, so a larger part of the sky is visible than inland, where trees, buildings, etc., block the view of the horizon. Also, the horizon sky is brighter than the overhead sky. At or near the horizon the sky appears lighter blue than at the zenith, or even whitish. Looking vertically at the zenith is looking through one air mass; looking horizontally at the horizon is looking through 40 air masses. Although the atmosphere scatters short wavelengths at the violet end of the spectrum most effectively, 40 air masses scatters enough of even the longer red wavelengths that the horizon sky appears very light blue or even whitish. 40 air masses is enough to scatter all of the light. Greater scattering of light causes the near-horizon sky to be brighter. (Even the zenith sky appears blue rather than violet because the Sun emits more blue light than violet and the eye is more sensitive to blue light than violet.)


Minimum sea-level pressure and maximum wind speed intensity relationship in Hurricane Katrina (2005)

Generally the relationship is the lower the air pressure the more intense the hurricane. For example during the same hurricane season as Katrina (2005) which also happened to be a record breaking season for the number of hurricanes recorded in the Atlantic basin, hurricane Wilma was recorded as being the most intense hurricane ever to form in the Atlantic. It reached a minimum air pressure of 882 millibar which was a record low. The corresponding maximum wind speed during this period of intensification was 185 mph. Hurricane Katrina was also a category 5 hurricane and reached a minimum air pressure of 902 millibar with maximum wind speeds at this pressure of 175 mph. Katrina of course striking where it did caused far more destruction even though it was the less intense hurricane of the two:

http://en.wikipedia.org/wiki/Hurricane_Wilma

http://en.wikipedia.org/wiki/Hurricane_Katrina


What are the physical upper bounds on the magnitude of an earthquake?

Earthquakes involve slip on faults, most of which occur on plate boundaries.

Now the width of a fault is usually limited by the downdip limit of the brittle ductile transition. E.g., in case of vertical strike slip faults this limit is between 10-20 km. In subduction zones this limit can be larger as the fault/interface is inclined.

The theoretical length of the fault is limited by the length of the plate boundary. It is impossible to have a fault with a length greater than the circumference of earth.

The final variable is slip. Average slip, based on empirical relationships, doesn't exceed more than 5-15m (rocks can accumulate only so much strain). Though locally it is possible to have slip as high as 50m (e.g., in the case of the Tohoku earthquake.

So for a plate boundary fault which exactly splits the earths brittle upper crust into two halves (in a single earthquake) with an average slip of 15 m, assuming a modulus of rigidity of 30GPa (mean for upper crust) we have:

Moment = Fault_area x rigidity x slip

which for our hypothetical scenario is equal to

= ((2*pi*6371000)*20000)*(30e9)*(15)

or

3.6E23 Nm

which is about Mw9.7.


I can't provide numbers, but a hopefully reasonable outline for your own calculations:

All that is required for oil to form is a source-rock brought to the right depths in a sedimentary basin and the oil migrating into a host-rock. If it is economically profitable (See Footnote) it goes into the global reserve calculation. (Petroleum Sedimentology Winfried Zimmerle, H. Zimmerle)

All you need to calculate the oil production is an estimate of the volume of host-rock that is currently under those conditions in sedimentary basins around the world.

As you can see there is a staggering area of Earth covered by sedimentary basins, and all those basins have a certain volume under oil generating conditions.

You will probably also need a rough estimate of how much oil can come out of an average source-rock, and how much will be trapped in economically profitable host-rock traps. Maybe a factor that takes into account the basin type, would also help to improve the calculation (Compressional basins would have a lot of antiform traps, while extensional basins have tilted bed traps).

I have the feeling that the total oil inventory of Earth is probably a Logistic function. Once all the oil traps are filled all the excessive oil is lost to migration or too much heat. Empty traps would mean that oil would find a place to accumulate. So it might even be a self-stabilizing system (but not in human-time-scale, but let's see how long we last).

I think that this would yield an order-of-magnitude answer. It is possible that somebody already made these calculations and I would love to see the numbers.

Footnote: Oil, like all resources, follows mining economics. If you earn money, you mine, if you loose money, you leave. This also means that if more money can be earned, there are also more deposits worth the effort. Calculations with today's reserves are almost useless, because they can't predict what people will be willing to pay for oil in the future. Even if mining becomes unprofitable, we might produce synthetic oil, just because it is a convenient chemical (energy stored in relation to mass, diffusivity, and danger). We kind of already have that with rapeseed oil, which sadly can get a better price to power rich countries cars, than feed poor countries people.


Yep, mining can trigger earthquakes.

According to a Scientific American article:

  We've been monitoring [The Geysers] since 1975. All the earthquakes we see there are [human] induced. When they move production into a new area, earthquakes start there, and when they stop production, the earthquakes stop.

This is talking about geothermal power. They create small little fractures, which cause tiny earthquakes. They then harness this power for electricity.

Earthquakes can also be caused by coal mining and other mining, according to this study:

  Klose has identified more than 200 human-caused temblors, mostly in
  the past 60 years. "They were rare before World War II," he said.

  Most were caused by mining, he said, but nearly a third came from
  reservoir construction.

  Oil and gas production can also trigger earthquakes, he added.

  Three of the biggest human-caused earthquakes of all time, he pointed
  out, occurred in Uzbekistan's Gazli natural gas field between 1976 and
  1984 (map of Uzbekistan).

Another study also concluded this.


What tools are available to build unstructured grids for ocean models?

The simplest is triangle http://www.cs.cmu.edu/~quake/triangle.html which is providing lib form many other more advanced packages. You can create poly file and create "holes/islands" in grid etc. Easy to make simple grids.
Another more advanced / gui is xmgredit where you can create/modify grids.
Blue kenue  etc..
use the force luke, do a google and it will popup many other packages,
I just wrote a few which are free and for 2D ocean applications.


Filtered pressured oxygen 80 miilion years ago

What filter?  Modern vertebrate blood is always red (with just one exception AFAIK: https://en.wikipedia.org/wiki/Channichthyidae ) because it is based on hemoglobin.  Given that birds, which descend from one branch of the dinosaurs, have red blood, it's likely that the dinosaurs did as well.  Likewise plants are mostly green due to the chlorophyll used for photosynthesis, another thing that would be strongly conserved by evolution.


Why does relative humidity seem to correlate with high temperature (at least where I live)?

In coastal New Jersey, relative humidity is maximal in the early fall when the ocean temperature is warmest, and minimal in early spring when the ocean is coldest.  However, the monthly variation is rather small:

Atlantic City, New Jersey:

70 January
69 February
67 March
66 April
71 May
73 June
74 July
76 August
76 September
75 October
73 November
71 December
72 Annual

Newark, New Jersey

65 January
63 February
60 March
58 April
62 May
63 June
63 July
66 August
68 September
66 October
67 November
67 December
64 Annual

source: https://www.currentresults.com/Weather/New-Jersey/humidity-by-month.php


How is it possible to use up the water in a region?

This is a really complex problem and would require a really detailed explanation about atmospheric circulation, meteorology and hydrology.

The short answer to your question is that water is going somewhere else. If you look at the studies about moisture recycling, among the others van der Ent et al 2014 or 2010, you can see that the precipitation that generates from locally generated moisture is just a minor fraction, and usually is higher in very wet areas. So, your assumption of the "few hundreds kilometers" is generally wrong. Considering a very wet area like the Amazon forest, you can see that the moisture locally generated is the major source (about 70% in quantity) of the precipitations in South-Eastern Brazil. This is due to the atmospheric circulation and the topography of the continent.

Source van der Ent et al 2010.

To fully answer your question, both in case of precipitation and in the case of underground percolation, the water used locally in agriculture or other uses, would go to contribute to other drainage basins (both in the cases of surface water and underground aquifers).


Temperature images are calculated from microwave and infrared data. So in principle yes.

See https://en.wikipedia.org/wiki/Satellite_temperature_measurements?wprov=sfla1


Why don't weather forecast models normally take solar eclipses into account?

Total solar eclipses are rare.  Globally, they only happen every 18 months.  In any given spot, they are much, much rarer, with a recurrence period of many hundreds of years.

Solar eclipses are localised in time and space.  Although model resolution may be just about small enough (in time) to resolve the totality, it only has a limited impact.

One could implement solar eclipses in weather forecast models, but there's plenty of more important things to worry about improving.  Operational weather forecast models are complex beasts, so you really want to change things only if it may yield a significant improvement.  The potential improvement of implementing a consideration of solar eclipses is minimal, so it's simply not worth the effort or the risk.

Experimental models are a different category and as you have seen, eclipses have been implemented in those.  But the risks involved are much smaller; nobody really cares if experimental models go totally wrong, but you really don't want to be responsible for breaking the operational weather forecast model.

You might be interested in this article on The weather’s response
to a solar eclipse that  my colleagues wrote.


I don't know if there is a definition of the difference.  Sea caves are typically erosional features not solutional and do not have much length like typical limestone caves so to restrict them to only being a cave based on a totally dark section would force the reclassification of many sea caves to something else.

Typically an arch has an opening diameter greater than its length.  In our parts, Pacific Northwest North America, a sea cave can be just about any opening in the cliff where there is a section that is continuously shaded.  The cave can have multiple entrances.


Having had some time to do some digging (hahaha), I have as close to an answer as I believe is possible.

Small update just because: one of the smaller sinkholes has dangerously grown, in a way that I wouldn't believe if I didn't see it.  It has widened slightly to about 45-60 cm, but grew substantially deeper.  With a tape measure I clocked it in at 3.3m.  No joke.  It's pretty much a death trap to small animals or children.  I do not take my children back there anymore nor does anyone else seem to play there, fortunately.

Onto answering my question.  This is Florida, the land of sinkholes, and it seems that the assumption made by all parties involved is that this is an actual sink hole, and not some obscure side effect of the drainage area.  After querying my HOA I learned that the area is owned/managed by the local county government.  It doesn't sound like they bother doing geological studies (because sink holes are so common around here), but instead just fill sink holes in as they appear to avoid liability.  They are actually aware of the larger hole and put it on an "official" sink hole map (which will probably have a minor effect on my insurance rates).  They will also fill it in.  However, they are being quite slow about actually fixing it (which is a surprise because of the potential liability issues).

From what I have read on various government sites, sink holes around here are assumed to be fairly independent, i.e. a sink hole within 50 feet of your home doesn't imply that your house is any more likely to experience damage from a sink hole than any other house in the general area.  However, since the organization responsible for filling the hole is not going to be performing a geological survey, nor are they likely to bother consulting professionals, a best guess is the best I'm going to get.


Result of floating-iron-balls in the mid-pacific?

I take it that your iron balls are hollow and made of rust resistant steel. It would be a fiendishly expensive project, but I doubt it would have the result you suggest. The iron balls would have to be linked together by chain or rope to prevent them dispersing in ocean currents and ending up on beaches around the world, like the cargo of plastic ducks which fell overboard from a ship about ten years ago.

Such a contrivance would represent a hazard to shipping, so no government would be willing to spend the huge amount of money it would cost. The whole thing would probably end up on the beach of some Pacific island and cost a fortune to remove.

The problem of plastic in the ocean is certainly a serious one, and something needs to be done about it, but this is not the solution. Perhaps an internationally financed ship dedicated to seeking out rafts of plastic at sea and disposing of them might help, and would certainly be much cheaper and easier to control than your million tons of iron balls.

A world-wide educational campaign aimed at teaching people the damage caused by dumping their rubbish on beaches, in rivers, and from ships might have some effect in reducing the amount of rubbish which ends up in the sea. I always use an ordinary plastic shopping bag a couple of dozen times before it starts to fall to pieces, and then I put it in a bin bag to go to landfill. If everyone did the same it would be a major step in the right direction.


How will climate change affect the extent of the Sahara Desert?

Based on past  events supported by archeological finds  climate change will affect it.
Here is a short quote from an about.com referencing National Geographic

  "... recent excavations at the site of Gobero in Niger indicate.
  Gobero is a cemetery site, including at least 200 human burials
  located on top of a ridge or set of ridges, sand dunes with a hard
  calcrete-fringe. These burials occurred in two periods of settlement:
  7700-6200 BC (called Kiffian culture) and 5200-2500 BC (called
  Tenerean culture).

  There, explorations by a team led by National Geographic
  Explorer-in-Residence and University of Chicago paleontologist Paul C.
  Sereno, have illuminated some small part of the last 10,000 years of
  the Saharan ecosystem. "

Some references cited include

Sereno, Paul C., et al. 2008 Lakeside Cemeteries in the Sahara: 5000
Years of Holocene Population and Environmental Change. PLoS ONE
3(8):e2995. Free article download available

Green Sahara: National Geographic Magazine September 2008.

  People lived on the edge of the desert thousands of years ago since
  the last ice age. The Sahara was then a much wetter place than it is
  today. Over 30,000 petroglyphs of river animals such as crocodiles[8]
  survive, with half found in the Tassili n'Ajjer in southeast
  Algeria.... The modern Sahara, though, is not lush in vegetation,
  except in the Nile Valley, at a few oases, and in the northern
  highlands, where Mediterranean plants such as the olive tree are found
  to grow. The region has been this way since about 1600 BCE (aka as BC
  or  4600 years ago), after shifts in the Earth's axis increased
  temperatures and decreased precipitation.

Citation: American Geophysical Union. "Sahara's Abrupt
Desertification Started By Changes In Earth's Orbit, Accelerated By
Atmospheric And Vegetation Feedbacks." ScienceDaily. ScienceDaily, 12
July 1999. .

Within the Holocene era, roughly the last 11,000 years, meaning the time frame within which the Western Sahara was sufficiently habitable to support a cemetery,  we have experienced a  "little ice age". The Holocene is generally described as beginning at the end of the last glacial period.

There has been climate variation during the Holocene such that the Sahara could support human life. It is fair to extrapolate that any future climate change will also affect the Sahara.

If you look at a world map you will see that the great dry deserts pretty much center  around the 20 degree latitude. Proximity to a large body of water does not mean that the  landmass can support vegetation. The Namib desert is south Africa stretches to the Atlantic coast as  the Atacama in Chile   has a very long boundary  with the Pacific. (The Atacama is also the driest place on earth)

If there is going to be an affect on a desert from climate change , it is possible that the  desert could extend to a major coast line. It would be reasonable that the North African coast could undergo desertification. It  is already  coterminous with the east and west coastal borders of Africa. If it expands , it can go north  or south. It already approaches the Mediterranean coast

Presumably the Sahel could also become drier and there is some indication this has been happening. The Sahel is where we find the great savannahs. That  region is most at risk for increased temperature or aridity. Movement in eh other direction- milder temperatures and  more  rain would be beneficial  and supportive of  animals and human habitation.

The arid region and the mean temperatures in the western Sahara are sufficiently  large that it seems unlikely the Hadley cell formation would be affected, but I am not a meteorologist, so I defer to  them on that point.


Is there an estimation how much organic matter there is still in the ground?

There are estimates produced my the major coal, gas and oil producing nations, but there are large error bars for some of them.

Wikipedia has oil, gas and coal split down by country - well worth a read of this or the CIA World Factbook, especially on the description of the various categories of oil reserves (Proven and Unproven and the various estimation methods used to work out how much is actually likely to be retrievable) but in summary:

World Coal Reserves - 909,064,000,000 tonnes
World gas reserves -  175,400,000,000,000 cubic metres
World oil reserves -  1,324,000,000,000 barrels

Now these numbers may not mean very much unless aligned with production and usage rates.


How far upstream would severe sea level rise (1m) noticably affect a large river?

This is both a simple and complex answer.

The simple bit is that a 1m rise in sea level would impact the river to a point 1m higher than the current point (with a slight error margin dependent on flow rates etc)

The rise itself over the next 85 years will not push back along the river (as Michael mentioned) as it's not like a tidal bore such as the Severn Bore.

The complex bit is that the 1m rise could be along an estuary, or across winding wetlands, or a wide delta or other feature, so the change to river flow could actually be quite catastrophic. And these effects could impact very far upstream, especially in the case of a river such as the Rhine, with a heavily populated floodplain. Wikipedia notes the last 50km of the Rhine are at 0m elevation, so that's an incredibly large possible impact area.


About meddies: what are they? How do they form? How are they maintained?

Meddies are anticyclonic (rotating clockwise) lenses of warm salty Mediterranean Water that travel through the North Atlantic between ∼500 and 1500 m depth. They are observed as large temperature, salinity and velocity anomalies (Richardson et al., 2000). Meddies are typically 40–100 km in diameter with their core being 500–1000 m thick.

Meddies separate from the Mediterranean Undercurrent (the main Mediterranean outflow) as it flows through abrupt topographic changes like major canyons. Each year between 15–20 meddies are formed off southern Portugal predominantly at two sites (Bower et al., 1997): Cape St. Vincent (37° N) and Extremadura Promontory (39° N). They can be detected by their surface signature in surface temperature and sea level anomalies (Oliveira et al., 2000). A large percentage of the meddies formed collide with large seamounts decay while some travel west on the north side of the seamounts and then travel southwest near Cape St Vincent toward the Canary basin with translation speeds of a few cm/s and clockwise rotation periods of 4 to 6 days (Richardson et al., 2000).

(P.L. Richardson: "Tracking Ocean Eddies", American Scientist 81, 261--271, 1993. Fig 10. http://josvg.home.xs4all.nl/Dundee/meddies/index.html)

Meddies can have maximum salinities around 36.5 and maximum temperatures around 13°C and they are observed as large anomalies (salinity anomaly ~1 and temperature anomaly ~4 °C) as they travel westward into cooler and fresher water. During their trip, the Mediterranean water inside the meddy slowly mixes with the surrounding Atlantic water and the salt anomaly progressively weakens until the meddy dissipates. The main processes causing mixing occur at the boundary of a meddy where the largest gradients of temperature and salinity exist and are double-diffusion and thermohaline intrusions as large as 25 m thick (Meunier et al., 2015).

From Tychensky et Carton, 1998. (http://outreach.eurosites.info/outreach/DeepOceans/station.php?id=10&page_inc=fact)

Meddies average lifespan is around 1.7 years although some were observed for more than 5 years (Richardson et al., 2000). During that time they travel distances up to one thousand kilometers and their maintained mostly because the core of the meddy tends to have a doubly-stable stratification (Armi et al., 1989). Up to 29 meddies may coexist in the North Atlantic at the same time (Richardson et al., 2000).

From Univ. of Delaware (http://www.spaceflightnow.com/news/n0603/21whirlpools/)


Do humans cause a DST-related shift in average daily temperatures?

Firstly you need to define what you mean by average daily temperature. What algorithm are you going to use to compute it (from several time spaced measurements), why and what do you think the result represents.

Obviously if you use a measurement which is going to be affected by very local anthropogenic activity (e.g. cars) you can expect timing of activities to affect individual measurements. a measuring station which is going to be thus affected is not really going to be useful for anything wider or general    though.

When siting weather stations we try to find locations which are not subject to such local disturbances. Ideally well away from any heat producing apparatus (e.g. fixed a/c units), heated buildings, variable traffic and so on. Locations in open non urban areas are preferable for understanding changes in the weather and climate. Past locations thus chosen however have often been compromised by the expansion of nearby housing or industry as populations and cities have expanded. This is why you sometimes see references to Urban Heat Islands (UHI) in discussions of climate measurement.


sliced (like glass window)

Window glass is not sliced into sheets. It is made as sheets from the beginning.

Since you're looking for a naturally occurring mineral that can be made into a glass-like material, look no further than muscovite.

Because your planet has nice and big crystals, it most likely come from pegmatites, which is a type of rock that has large crystals and many gemstones we know today come from pegmatites (emerald, tourmaline, topaz, kunzite, etc). Pegmatites also have huge crystals of muscovite as well, in some rare occasions several metres wide. Muscovite can be easily split into sheets that are flexible and mostly transparent. Not the best glass material (because it is not glass after all), but almost as good. Quoting from the Wikipedia page:

  The name muscovite comes from Muscovy-glass, a name given to the mineral in Elizabethan England due to its use in medieval Russia as a cheaper alternative to glass in windows. This usage became widely known in England during the sixteenth century with its first mention appearing in letters by George Turberville, the secretary of England's ambassador to the Russian tsar Ivan the Terrible, in 1568.

Here's a good video showing how this is working.

So the inhabitants of your planet can mine the other crystals in the pegmatite for currency or whatever, and use the muscovite as building material.


Does Magnetic Deviation depend on altitude?

Technically yes, but practically, usually no.

The magnetic field varies in three dimensions and the variations are not parallel to the Earth's surface. However, horizontal distances varies usually on a larger magnitude than elevation and for everyday use, the declination is only based on horizontal position.

The common model for the Earth's magnetic field, IGRF-12 (International Geomagnetic Reference Field) uses the radial distance from the center of the Earth (r) in relation to the geomagnetic conventional Earth’s mean reference spherical radius (a). In other words, the elevation. (a/r) will usually be almost 1, and the difference is less than any other uncertainties in the measurements, e.g. deviation due to magnetic anomalies.

The magnetic field is often calculated by using the published model and this code. As you can see (the code is rather easy to read), the vertical component is used to estimate the magnetic field for every location.

Online calculators are often used to correct declination for navigational purposes:

NOAA's calculator doesn't include elevation and is calculated at sea level.
BGS's and GA's calculators does, but the elevation have a small impact on the declination. Try it to see!

Simpler models, e.g the dipol model also suggest how the magnetic declination varies with distance from the Earth's magnetic center. The approximation work rather well at low latitudes and at the Earth's surface. It can also be used to model Earth's magnetic field in an astronomical context.

Apart from declination, there is also an inclination to take into account. Near the magnetic poles, the compass needle will not be horizontal, but get a dip. This can make normal field compasses almost useless near the magnetic poles (trust me, I tried..).


Relation between molecular mass and retention of a gas on a planet

I didn't really understand where did this "one-sixth of the escape velocity" figure come up from.

The "one-sixth of the escape velocity" a ballpark number. As a general rule, three sigma events (events that are three standard deviations from the mean) happen all the time, while twelve sigma events are so very, very rare that they can essentially be ruled out. Six sigma events are rare but do happen. In a logarithmic sense, six is halfway between three and twelve.
A bit less hand-waving, it can be shown that the Jean's escape flux (which is what your text is addressing) is proportional to $v_s \, (1+\left(v_e/v_s\right)^2)\,\exp\left({-\,\left(v_e/v_s\right)^2}\right)$ , where $v_s$ is the expected value of the magnitude of the three-dimensional velocity of the gas at the top of the exobase and $v_e$ is the escape velocity at the top of the exobase. That factor of $\exp\left({-\,\left(v_e/v_s\right)^2}\right)$ means that Jean's escape is extremely sensitive to changes in $v_s$.


What does the term "Snow Interval" mean?

Email response from Alex Jacques (Programming Support - MesoWest):

  The exact interpretation can vary between data providers to MesoWest,
  but in general it refers to the amount of snow that has fallen on an
  "interval board".  In several cases, stations have boards where
  snowfall is recorded, and then the board is wiped clean at set
  intervals (sometimes every 6 hours, every day, etc.).  It is a
  complementary way to measure snowfall from a storm system in addition
  to a total snow depth reading, so often snow depth and snow interval
  are paired together for stations in MesoWest.

EDIT: Why do we need snow intervals? https://what-if.xkcd.com/104/ explains: as more snow falls, the existing snow on the ground gets compressed. To measure snow depth consistently, the "snow board" must be cleared at regular intervals.


Highest land altitude a tsunami has ever reached (record)

The worlds highest recorded tsunami occurred during a landslide triggered by an earthquake in 1958 in Lituya Bay, Alaska. The landslide sent the water 524 meters high the other side of the valley and left its contours in the vegetation. According to whitnesses, it lifted a glacier tip above the surrounding mountain tops.

https://geology.com/records/biggest-tsunami.shtml

https://earthquake.alaska.edu/60-years-ago-1958-earthquake-and-lituya-bay-megatsunami

I think this was the highest run-up on records (let's see if i get topped). But there probably occurred higher ones in earth's history. Candidates are asteroid impacts (e.g. Chicxulub) or flank collapses on volcanic islands.


Is there a table with decomposition temperatures of common minerals?

I would have expected to find something here but there isn't a guide to ceramics there that I can find. This article and it's references may give you some guidance though. Found a limited table in this that will probably help too.


What, if any, scientific value do global soundscapes have?

Remote sensing using passive sonar and seismograms, which are
  acoustic or near-acoustic signals, works on the principle of the
  inverse problem. While the object or phenomenon of interest (the
  state) may not be directly measured, there exists some other variable
  that can be detected and measured (the observation), which may be
  related to the object of interest through the use of a data-derived
  computer model.

  Soundscape ecology is the study of sound within a landscape and
  its effect on organisms. Sounds may be generated by organisms
  (biophony), by the physical environment (geophony), or by humans
  (anthrophony). Soundscape ecologists seek to understand how these
  different sound sources interact across spatial scales and through
  time. Variation in soundscapes may have wide-ranging ecological
  effects as organisms often obtain information from environmental
  sounds. Soundscape ecologists use recording devices, audio tools, and
  elements of traditional ecological analyses to study soundscape
  structure. Increasingly, anthrophony, sometimes referred to in older,
  more archaic terminology as anthropogenic noise dominates soundscapes,
  and this type of noise pollution or disturbance has a negative impact
  on a wide range of organisms. The preservation of natural soundscapes
  is now a recognized conservation goal.

  Source: Wikipedia links referenced above.


Would it be wise to monitor real time human activity to anticipate earthquakes?

If you have no prior information that event B depends on event A, it's a logical error to claim event A causes event B just because you find they are correlated.

Let's say you collect a large data set of how people use their computer-mouse, and show that there is some change in a statistic of this data preceding an earthquake. That cannot not prove that the anticipation of an earthquake is causing people to behave differently, because the data will always correlate just as well with some other unrelated event C (such as a swing in the stock-market.)


Why doesn't the whole volcanic cone appear black?

The cooled lava might be covered by ashes. So depending of the amount of ashes and the wind you might have a black volcano or a gray volcano. Many volcanoes are formed by layers of lava and ash.

https://en.wikipedia.org/wiki/Volcano#/media/File:Volcano_scheme.svg


What is a reasonable range of values for resistance to heat flux?

Alec Bennett calculates resistance to heat flux values in an urban canyon as part of his MSc in meteorology dissertation: Heat Fluxes from Street Canyons.

The calculated values range from 76.6 to 84.2 and are based on measurements taken on May 18th and 19th 2004 from 08:00 to 17:00 (both days).

See the two tables in the Appendix on page 68 for the full range of values.

I have not read the entire thesis.  It's unclear to me what confidence I should place in these values.


Why are metals so separated in the Earths crust?

There are active geological processes that lead to separation of mineral constituents. A source material that contains specific primary minerals, with some transport mechanism (eg convection or liquid flows) to physically separate them and 'trapping' conditions that allow them to accumulate are all required. Processes that result in minerals being separated from the source material include  -

Magmatic - (within molten and partly molten magmas). Differential melting will allow specific minerals to melt and be squeezed out separately. Differential crystallisation will allow some minerals in a mixture to crystallise within a molten mass and (with changing temperature and/or pressure) to separate and reform as crystals and precipitate separately in more concentrated form in sediments at the base of a molten mass (or to rise where they are lower density than the surrounding material). Some materials can separate in their molten state, because they are immiscible (they don't mix or dissolve within each other), with similar separation because of differing density or pressure squeezing them out and solidify in concentrated forms.

Hydrothermal - minerals dissolving (usually in association with salts), with different temperature and pressures dissolving minerals preferentially. As liquid they can travel and come into contact with other minerals, resulting in chemical reactions, with potential for further differentiation.  Similar to differential crystallisation in magmas, specific minerals will crystallise and precipitate differentially out of concentrated water based solutions. Lots of sulphide mineral ore bodies were formed this way.

Physical process like erosion and sedimentation also separate and concentrate existing minerals.

(Answer in part from Wikipedia  - Ore genesis).


What's the difference between these most basic, first-order models for estimating runoff?

The models are similar in that they simplify the rainfall-runoff relationship into a few parameters, and essentially use some kind of first-order coefficient to partition rainfall into infiltration and runoff. The differences are mostly in what other parameters are brought in, such as initial abstraction in the SCS method (i.e. some capture of antecedent moisture conditions). You may wish to pick the method that best captures the information you wish to include in the calculation (or have available), such as drainage area. You can find more details about the implicit assumptiopns and ranges of applicability for each method (e.g. rational method).
In terms of other methods, there are many methods that use some similar forms of soil moisture, soil saturation, etc. to estimate the rainfall-runoff partition. For example, take a look at the Infiltration section (4.2) of the Raven Hydrologic Modelling Framework manual v2.8.
As to whether they are empirical, likely depends who you ask. Empiricism is likely more of a spectrum than a binary system. These are not simply linear regression equations and do capture some physics, although they are still clearly at least partially empirical since the coefficients are basically based on experiments to best fit results. I would likely describe them as empirical or semi-empirical, although I wouldn't spend too much time trying to split hairs for this question.


How long does it take air to circle the world?

It takes about 2 weeks for a mass of air to circle the globe along its latitude from West to east. I used to work for a French climate research lab in the 70s, and was based on Crozet island (South Indian Ocean) . At the time I was carrying atmospheric radioactivity measurements, and the French army was carrying nuclear test above ground in the pacific, I could see the radioactive cloud passing above me about 10 days later and then again about every second week after that and about completely disappeared after 6 months.
In the case you raise, you will benefit from cleaner air about one week after the decommissioning


How to generate inputs for the MUNICH model from the VEIN model

First, download a project with vein and estimate vehicular emissions.
Some projects are here: https://atmoschem.github.io/vein/reference/get_project.html
library(vein)
get_project(directory = "awesomecity")

Then open the file main.Rproj with Rstudio and source the file main.R
Then, run the following code

library(data.table)
library(eixport)
library(sf)
#> Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1
library(writexl)
library(vein)
library(units)
#> udunits system database from /usr/share/xml/udunits
# epsg 31983, projected UTM
co <- readRDS("post/streets/CO.rds")
st_crs(co)
#> Coordinate Reference System:
#>   User input: EPSG:31983
#>   wkt:
#> PROJCS["SIRGAS 2000 / UTM zone 23S",
#>     GEOGCS["SIRGAS 2000",
#>         DATUM["Sistema_de_Referencia_Geocentrico_para_las_AmericaS_2000",
#>             SPHEROID["GRS 1980",6378137,298.257222101,
#>                 AUTHORITY["EPSG","7019"]],
#>             TOWGS84[0,0,0,0,0,0,0],
#>             AUTHORITY["EPSG","6674"]],
#>         PRIMEM["Greenwich",0,
#>             AUTHORITY["EPSG","8901"]],
#>         UNIT["degree",0.0174532925199433,
#>             AUTHORITY["EPSG","9122"]],
#>         AUTHORITY["EPSG","4674"]],
#>     PROJECTION["Transverse_Mercator"],
#>     PARAMETER["latitude_of_origin",0],
#>     PARAMETER["central_meridian",-45],
#>     PARAMETER["scale_factor",0.9996],
#>     PARAMETER["false_easting",500000],
#>     PARAMETER["false_northing",10000000],
#>     UNIT["metre",1,
#>         AUTHORITY["EPSG","9001"]],
#>     AXIS["Easting",EAST],
#>     AXIS["Northing",NORTH],
#>     AUTHORITY["EPSG","31983"]]
head(co, 1) # units g/h
#> Simple feature collection with 1 feature and 25 fields
#> geometry type:  LINESTRING
#> dimension:      XY
#> bbox:           xmin: 328001.4 ymin: 7391129 xmax: 328036.5 ymax: 7391204
#> projected CRS:  SIRGAS 2000 / UTM zone 23S
#>        id            V1             V2             V3             V4
#> 1 1 [1/h] 275.088 [g/h] 140.0241 [g/h] 84.63286 [g/h] 86.81989 [g/h]
#>               V5             V6             V7         V8             V9
#> 1 195.8425 [g/h] 680.7458 [g/h] 1423.767 [g/h] 1719 [g/h] 1723.265 [g/h]
#>              V10            V11            V12            V13          V14
#> 1 1748.996 [g/h] 1600.077 [g/h] 1448.586 [g/h] 1378.825 [g/h] 1551.5 [g/h]
#>              V15            V16            V17            V18            V19
#> 1 1556.648 [g/h] 1538.186 [g/h] 1698.133 [g/h] 1655.548 [g/h] 1601.138 [g/h]
#>              V20            V21            V22            V23            V24
#> 1 1398.703 [g/h] 941.4398 [g/h] 709.3241 [g/h] 581.2601 [g/h] 407.1127 [g/h]
#>                         geometry
#> 1 LINESTRING (328001.4 739120...

# example of  polygon as buffer at center
st_bbox(co) %>%
  st_as_sfc() %>%
  st_centroid() %>%
  st_buffer(dist = 2000) -> polygon

# if you have another polygon, read it
# polygon <- st_read("/path/to/polygon.gpkg")

cob <- st_intersection(co, polygon)
#> Warning: attribute variables are assumed to be spatially constant throughout all
#> geometries

# Remove ID
co$id <- NULL

# split on vertex conserving mass
cos <- st_explode(cob)
#> Sum: 16542955.31
dim(cos)
#> [1] 372  27
# it adds length LKM and LKM2
# Should we remove streets shorter than 10 mts?
cos <- cos[as.numeric(cos$LKM2) > 10, ]

# remove LKM and LKM2
cos$LKM <- cos$LKM2 <- NULL

# We need to add units back, g/h
cos <- vein::Emissions(cos, time = "1/h")
head(cos, 1)
#> Simple feature collection with 1 feature and 24 fields
#> geometry type:  LINESTRING
#> dimension:      XY
#> bbox:           xmin: 331916.3 ymin: 7385767 xmax: 331922.9 ymax: 7385775
#> projected CRS:  SIRGAS 2000 / UTM zone 23S
#>               V1             V2             V3             V4             V5
#> 1 59.38562 [g/h] 30.22821 [g/h] 18.27042 [g/h] 18.74256 [g/h] 42.27821 [g/h]
#>               V6             V7             V8             V9            V10
#> 1 146.9585 [g/h] 307.3609 [g/h] 371.0953 [g/h] 372.0159 [g/h] 377.5708 [g/h]
#>              V11            V12            V13            V14            V15
#> 1 345.4224 [g/h] 312.7188 [g/h] 297.6588 [g/h] 334.9356 [g/h] 336.0469 [g/h]
#>              V16            V17            V18            V19          V20
#> 1 332.0614 [g/h] 366.5907 [g/h] 357.3973 [g/h] 345.6514 [g/h] 301.95 [g/h]
#>              V21            V22            V23            V24
#> 1 203.2367 [g/h] 153.1279 [g/h] 125.4816 [g/h] 87.88691 [g/h]
#>                         geometry
#> 1 LINESTRING (331916.3 738577...
# now we transform for the REQUIRED UNITS FOR MUNICH
# ug/km/h

# we have 24 hours in this case
hours <- paste0("V", 1:24)

for (i in seq_along(hours)) {
  cos[[hours[i]]] <- set_units(cos[[hours[i]]], ug / h)
  cos[[hours[i]]] <- cos[[hours[i]]] / set_units(st_length(cos), km)
}
plot(cos["V1"], axes = T)

etm <- to_munich(sdf = cos)
names(etm)
#> [1] "Emissions" "Street"
head(etm$Emissions, 1)
#>   i idbrin typo        xa        ya        xb        yb                   V1
#> 1 1      1    0 -46.64773 -23.62993 -46.64766 -23.63001 5462199660 [ug/h/km]
#>                     V2                   V3                   V4
#> 1 2780345076 [ug/h/km] 1680485867 [ug/h/km] 1723911918 [ug/h/km]
#>                     V5                    V6                    V7
#> 1 3888685780 [ug/h/km] 13517016236 [ug/h/km] 28270586844 [ug/h/km]
#>                      V8                    V9                   V10
#> 1 34132780053 [ug/h/km] 34217462106 [ug/h/km] 34728386913 [ug/h/km]
#>                     V11                   V12                   V13
#> 1 31771425772 [ug/h/km] 28763397272 [ug/h/km] 27378203813 [ug/h/km]
#>                     V14                   V15                   V16
#> 1 30806871891 [ug/h/km] 30909088139 [ug/h/km] 30542507720 [ug/h/km]
#>                     V17                   V18                   V19
#> 1 33718452534 [ug/h/km] 32872865695 [ug/h/km] 31792493506 [ug/h/km]
#>                     V20                   V21                   V22
#> 1 27772900557 [ug/h/km] 18693404826 [ug/h/km] 14084471885 [ug/h/km]
#>                     V23                  V24
#> 1 11541609851 [ug/h/km] 8083705065 [ug/h/km]
head(etm$Street, 1)
#>   i       length width height
#> 1 1 10.87211 [m]     0     30

# to export to CSV which supports bit64
data.table::fwrite(
  etm$Emissions,
  paste0(basename(getwd()), "_Emissions.csv")
)
data.table::fwrite(
  etm$Street,
  paste0(basename(getwd()), "_Streets.csv")
)

# to export to Excel
writexl::write_xlsx(
  x = etm$Emissions,
  path = paste0(basename(getwd()), "_Emissions.xlsx")
)
writexl::write_xlsx(
  x = etm$Street,
  path = paste0(basename(getwd()), "_Streets.xlsx")
)

Created on 2020-10-14 by the reprex package (v0.3.0)


SPI (Standardized Precipitation Index) for 40 years seasonal mean

The SPI statistic can be considered a standard normally distributed random variable $SPI \sim N(0,1)$. Thus the expected value, or mean, of the SPI statistic is $0$, and its standard deviation and variance are $1$.

If the mean of the distribution is zero, then by the central limit theorem, you would expect that the limit of your sample mean (the mean of ~40 years of data) would approach zero as your sample got larger. So yes, it is both possible and expected.

What may be causing your confusion is that SPI can be calculated for different time sets. If you are analyzing month by month, then I would assume that your dataset is divided by month. In that case, the SPI is calculated individually for each month, so that the mean of any month or set of months over many years would tend to zero, as per the last paragraph.

It would not make sense to calculate a monthly SPI from a 12-month mean divided by 12 (to give you a mean per month on an annual basis) In seasonal wet-dry climates you would have massively negative SPI value in the dry season, and highly positive numbers in the wet season. The monthly means are individually given an SPI statistic to allow apples-to-apples comparisons with the same month in other years.


Can the dew point temperature be more than drybulb temperature?

Dew point gives an indication of the moisture content of air; it is the temperature at which air can no longer hold water vapour.

The following graph shows the relations of dew point to air temperature (dry bulb) for various levels of humidity.

For humidity less than 100 percent, the air temperature is always higher than the dew point temperature and for a humidity of 100 percent air temperature equals the dew point temperature.

The dew point cannot be higher than the dry bulb temperature, it can only be lower of equal to it.


What is the most real-time method of determining SPI?

There are more up-to-date datasets that are available after registration and acceptance of the respective data usage licences.

E.g. two satellite-derived products

GSMaP https://sharaku.eorc.jaxa.jp/GSMaP/
TRMM 3B42RT https://mirador.gsfc.nasa.gov/

For a more comprehensive overview, including evaluation against rain gauge data, see Beck et al. 2017.

Beck, H.E., Vergopolan, N., Pan, M., Levizzani, V., van Dijk, A.I., Weedon, G.P., Brocca, L., Pappenberger, F., Huffman, G.J. and Wood, E.F., 2017. Global-scale evaluation of 22 precipitation datasets using gauge observations and hydrological modelling. Hydrology and Earth System Sciences, 21(12), pp.6201-6217.


Why do tropical cyclones not tear themselves apart?

The equation of motion for a fluid parcel in the atmosphere (in Cartesian space) is

$$\dfrac{D\mathbf u}{Dt} = -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F,$$

where $\mathbf u$ is the wind, $\rho$ is density, $p$ is pressure, $\mathbf\Omega$ is the angular velocity of the Earth, $\mathbf g$ is gravity and $\mathbf F$ is friction.  The derivative is a material derivative (Lagrangian perspective) where

$$\dfrac{D\varphi}{Dt} = \dfrac{\partial\varphi}{\partial t} + \mathbf u\cdot\nabla\varphi.$$

There is a non-dimensional number called the Rossby number ($Ro$) that determines when a flow behaves geostrophically.  This number is given by

$$Ro = {U\over fL},$$

where $U$ is a velocity scale, $L$ is a length scale and $f$ is the Coriolis parameter ($f=2\Omega\sin\phi$, $\Omega = 7.2921 \times 10^{-5}\ \text{s}^{-1}$, and $\phi$ is latitude).  When $Ro << 1$, the flow exhibits geostrophic balance.  This occurs when $L$ becomes large, which it does as the storm grows.  When I say the flow is geostrophic, what I really mean is that the net acceleration of a parcel is small.  In a tropical cyclone the isobars are roughly circular and this curvature gives rise to the gradient wind balance.

The gradient wind is the balance of the pressure gradient force, Coriolis force and centripetal acceleration.  In this flow, just as in geostrophic flow, the wind will follow the isobars, flowing cyclonically around the center of low pressure, though slower than a geostrphic flow with the same pressure gradient.  Close to the ocean surface friction plays a role, and for the near surface winds the friction will cause the wind to be slightly deflected toward low pressure, or inward across the isobars.

Close to the center of the storm, in and near the eyewall, the length scale $L$ is reduced and the Coriolis force places a smaller role.  Here the flow attains cyclostrophic balance -- a balance between centrifugal and pressure gradient forces.

The gradient and cyclostrophic balances explain the wind rotating around the storm and surface friction will give a radially inward component at low levels, advecting angular momentum toward the center of the storm.  Convection in the eyewall will lift air to the tropopause where it will flow anti-cyclonically (due to the thermal wind) away from the storm before subsiding.  The core of the storm is warm and the air there is subsiding, creating the cloud free eye. The flows around the storm are balanced flows and the flow inward/upward/outward/downward is a thermodynamic carnot engine.

This gives us a fairly stable setup and this is why once a tropical storm forms it tends to persist rather than tear itself apart.  The key to sustaining this balance is a warm ocean surface and weak vertical windshear.  If you take away the warm ocean the storm will start to spin down and if you have strong shear you will disconnect the lower and upper level circulations and the storm will weaken.


Your best bet is probably OpendTect.

It's not quite what you asked for. OpendTect is a desktop application and does not use HTML/JavaScript for display. It is dual licensed; the free version is licensed under the GPL. It will read wells and seismic no problem, but I'm not sure about FMI in the free version.

Agile started G3.js, a JavaScript library based on D3.js for logs and seismic, but we didn't get very far. (I'm the founder of Agile; I'd welcome a reason to start that project up again.) Agile also has welly, a Python library for well logs and lithology.

There are lists of other open source tools for geophysics and geology on Wikipedia.


Theoretical answer:

You need to measure extinction angles. If it is always extinct when aligned to cleavage or crystal faces, then it is orthorhombic. If it sometimes aligns and the colour is consistent, it's monoclinic. Otherwise it's triclinic. You do not need to know how cleavage is oriented with respect to the axes in advance because there very few orthorhombic minerals with oblique cleavage (if any at all).

Practical answer (and a rant):

I have no idea why is this still taught in 2016. The motivation of this thing is to know optical properties so you can derive chemical information from them. These days it's probably cheaper and faster to put the sample in XRD or SEM-EDS to know what it is. Even when three colours exist, it is usually very subtle and you will need a lot of self-convincing to see the third colour on its own and not as a combination of the other two. Then there's the issue of a real mineral actually having a proper crystal shape and cleavage (good luck doing this on a 10 micrometre wide anhedral crystal in a thin section).


The $\tau$–$p$ time domain $t$ is a function of offset $d$, so the result is an array of size $n_t \times n_d$, where $n$ is the number of samples.

The inputs are a vector $\tau$ of travel time at zero offset, or $t(0)$, an array $p$ of ray parameter, which is in turn a function of velocity $V$ and angle, and a vector $d$ (usually called $x$) of offset.

Here's an example of some visualizations of the $\tau$–$p$ domain from a paper by Sergey Fomel; they might help explain what I mean by an 'array' — you can think of them as images:

The resulting travel-time $t(d)$ is an array of size $n_t \times n_d$, where $n$ is the number of samples. For a given offset at a given time sample, the result is a scalar — a single value of $t$.

By the way, stevej's answer is a great explanation of how exactly to calculate the ray parameter term, given limited information. Do follow that link to Yilmaz, and maybe also read the Radon transform article.


What percentage of Earth's surface is arid?

It will depend on the exact definition of "arid" and the period of time. But using the widely used and accepted Köppen climate classification, "arid" would correspond to the four climates in climatic group B: "Dry (desert and semi-arid) climates". Using the most up-to-date present climate data (2006) provided by the WORLD MAPS OF KÖPPEN-GEIGER CLIMATE CLASSIFICATION at 0.5° of resolution, that looks like this (in an equal area projection):

We get that the four arid climates (group B), add up to $4.401 \times
 10^7 {km}^2$ of a total of $1.527 \times
 10^8 {km}^2$ inventoried in the dataset (A good match for the figure of of global land area of $1.489 \times 10^8 km^2$ listed by wikipedia), leading to a grand total of 28.8% of Earth's land surface corresponding to arid climates.


What reflects UV radiation more: stratus clouds or cumulus clouds?

According to the below albedo rating diagram (percentage is reflection of incident radiation) cumulus cloud is the greater total spectrum reflector so it will reflect more UV that equivalent stratus formations.

Do note that water vapour does however absorb the vast majority of UV (≈100nm) that it intercepts as we can see in this diagram:

So overall cloud UV reflectance will be quite low.


Calculating a cloud cover index based on comparison of horizontal and tilted irradiance from pyranometers

Not being an expert in the subject, I agree with your hypothesis. But, I think that what you are measuring with the difference in the readings is the anisotropy of the illumination. In very cloudy skies, the amount of light from all directions in the sky is the same (that's why you can't tell where is the Sun). In a extreme case, like the condition refereed as whiteout (dense fog over snow) a pyranometer on any direction would measure the same value.

However, I don't think that can be used to calculate cloud cover in the common sense, as the anisotropy will be very high even if there is a small gap in the clouds that let the Sun light through, so your conversion into cloud cover would only work when the cloud cover is homogeneous, and would fail when it is patchy.

I would think that you have better chances to estimate clod cover if you have one pyranometer shielded from direct sunlight , so you can measure how much energy is coming from the sky. However, you would only know the cloud cover in that area, and still with many posible source of error.

Measuring cloud cover is a difficult problem. Naked‐eye observation of sky cloud cover has widely resisted automation. Some successful approaches use analysis of images like in Whole sky cameras or more sophisticated whole sky imagers.

However, there are methods developed to estimate cloud cover based on standard AWS data. Like APCADA, that uses longwave downward radiation, temperature, and relative humidity measurements. It is described in the paper "Automatic cloud amount detection by surface longwave downward radiation measurements", that reports that:

  APCADA estimates. Results show that about 86% of all cases agree
  within ±1‐octa cloud amount difference for sites with moderate
  climate, 82% for sites with arctic climate, and 78% for the site with
  tropical climate.

I would think that for the direction technology have taken, the most affordable options will go in the direction of having a camera taking pictures of the sky (in infrared if you can), and having and algorithm to analyze it and evaluate cloud cover. I found this paper that talks about that. It looks like the Red/Blue ratio is a good indicator to classify an image pixel as cloud or cloudless.


How did Earth's atmospheric layers get their names?

Who gave the names Troposphere and Stratosphere

The stratosphere was firstly discovered by Léon-Philippe Teisserenc de Bort and Richard Aßmann (they did not cooperate) around 1900. Teisserenc de Bort denoted that layer as 'zone isotherme' in his publication on his discovery. However, he published in French. I remember to have read somewhere - not sure where - that he gave the two names 'troposphere' and 'stratosphere' to the two lower layers after discovering the existence of a quite distinct second layer. Unfortunately, I do not find the reference anymore. In the article Hoinka (1997) you will find some information about the discovery of the stratosphere.

What the Names mean

Troposphere

tropos (greek): turn(ing)

Turbulent mixing is relevant in this layer of the atmosphere => Turbulent Mixing Sphere => Troposphere

Stratosphere

stratum (latin): something which covers something else (pavement, blanket)

This layer of the atmosphere, which is not dominated by turbulent mixing, covers the lower turbulent layer => Covering Sphere => Stratosphere

Mesosphere

mesos (greek): middle
This part of the atmosphere is the third of five (from humans defined) layers of the atmosphere => Layer in the middle (not by distance/height but by counting layers) => Mesosphere

Thermosphere

thermos (greek): warm, heat

This layer can be heated to above 1000 °C by the sun. However, it does not feel 'warm' because of the low 'air' density. => Heated/hot layer => Thermosphere

Exosphere

éxo (greek): outside, external

This layer is the most outward located layer of the atmosphere. => At the outer side located => Exosphere


In the past, why did the levels of individual greenhouse gases rise and fall at the same time?

CO2 and methane both have natural feedback loops that can cause increasing temprature to release more of both, which in turn causes more warming which causes more release and so on and so forth. This is one of the big worries about human caused greenhouse gasses, that they will trigger these feedback loops causing far more drastic warming. Negative feedback loops also exist so making it colder can trap more or release less of these gases. I will give a few examples of those feedback loops.

Methane hydrates, A lot of the seafloor has methane hydrates trapped in the sediment, if you warm that material it releases methane gas, a lot of it. This material builds up very slowly but can be released very quickly, so there is plenty available to warming water to release. Higher pressure can mitigate this but the temprature has a stronger effect than pressure from rising sea levels. Of course if you cool the sea more of this methane is trapped as hydrates reducing the amount in the atmosphere.

Permafrost also contains methane hydrates and other organics, the cold and ice keeps them inactive and trapped but warming it triggers the release of both methane and trapped carbon (which is released as CO2). so as the polar regions warm the release out these stored gasses, if they get colder they trap more it.

Biology, there is a really interesting feedback loop in microbial life, ocean and wetland life in particular respond to warmer temperatures by releasing more CO2(or absorbing less), how much is difficult to estimate but that they do increase CO2 has been repeatedly confirmed even if weak on a geological time scale this will quickly add up.

This effect is much stronger in wetlands and wetlands have the additional effect of releasing more methane with warming temprature at the same time, Methanogenesis. additionally  they also convert CO2 into methane and how much is based on CO2 concentration and temprature, so increasing CO2 will result in more methane directly.

Ocean circulation, warming the planet changes ocean circulation patterns, and the current pattern with a lot of mixing due to wide differences in temperature. is really good at absorbing methane and CO2 into sediment and microorganisms. warmer oceans result in less mixing which means less gases released by other means getting absorbed.

On a geologic scale the movement of continents can affect all of these, so that adds one more thing that will tend to change both in the same ways.


Is there limestone under the Oregon Coast Range?

I'm not familiar with the Oregon Coast Range, but limestone is such a ubiquitous and widespread rock that your friend is almost certainly right. For strata to be limestone, they need to have been under the sea when they were laid down. The fact that some are found today near the tops of mountains only means that plate movements have uplifted them since they were formed. They might easily have become overlaid with igneous rock, volcanic tuffs, sandstone etc,but if you go down deep enough the probability is that you'll find limestone somewhere. You usually don't have to go down very far, and there are usually exposures that reveal it. Limestone (calcium carbonate) is often a good place to find fossils.


What is this stratefied limestone sphere?

Your fossils look like Stromatolites to me.  Stromatolites start as a film of cyanobacteria on the substrate in marine and sometimes freshwater environments.  I am not sure if the bacteria capture sediment or weather the carbonates form on the bacteria themselves but overtime they develop layers of carbonate and other mineral deposits which later became fossilized.  There is a wealth of information about these on the internet.  Stromatolites are still found today, Living Stromatolites.  Wikipedia has a good description of stromatolites Stromatolites on Wikipedia.


Abiogenesis: Formation of Lipids from Montmorillonite

Good question! One that's stuck with me since reading about clay's purported role in providing scaffolding to early organic molecules in a Scientific American article from the late '80s. Many years later I ran into a bonafide clay scientist who said "Of course!" when I asked her about clay's role in establishing early life.

Anyway...

I suspect that molecular attraction and ordering is more of a driver than a specific chemical process (but I'll claim ignorance here). What I have found is a slide from a talk entitled "Chemical Evolution Theory of Life’s Origins" given at the State University of Stony Brook's Astronomy department in which the author highlights an underappreciated chemical property of clay sheets, namely that of mirror symmetry on opposing crystal faces. Recall that these sheets are actually molecular-thin crystals attached to each other by very weak bonds, the implication being that the crystal surfaces themselves are mildly charged providing a surface for monomers to automatically align:

Every physical separation between these crystals provides identical faces on opposing sides of the void. Do these faces act as holding jigs for water-borne monomers to line up into lipids? The authors lab results confirm this. However he provides no details for how, specifically, that catalysis happens.

It's worth noting that this (clay-based) process sounds almost exactly the reverse  of chemical cracking of long-chain crude petroleum compounds in which naturally occurring molecular sieves are used to break bonds (and allow re-ordering of resultant fragments). From Wikipedia:

  The catalytic cracking process involves the presence of acid catalysts (usually solid acids such as silica-alumina and zeolites) which promote a heterolytic (asymmetric) breakage of bonds yielding pairs of ions of opposite charges, usually a carbocation and the very unstable hydride anion. Carbon-localized free radicals and cations are both highly unstable and undergo processes of chain rearrangement, C-C scission in position beta as in cracking, and intra- and intermolecular hydrogen transfer. In both types of processes, the corresponding reactive intermediates (radicals, ions) are permanently regenerated, and thus they proceed by a self-propagating chain mechanism. The chain of reactions is eventually terminated by radical or ion recombination

Here's another important paper that I wish I had more time to read: Origins of life: From the mineral to the biochemical world, in which, among many other important things, the author writes,

  One of these involves enantioselective adsorption on crystal faces.
  Hazen et al. [13] have investigated the adsorption of the two forms of
  an amino acid (aspartic acid) on well-defined faces of calcite
  crystals. These faces themselves already possess the property of
  chirality, i.e. the arrangement of atoms exposed on the surface is not
  superimposable to its mirror image...

This paper is a pretty good resource. This "brief guided tour through “mineral-based” prebiotic scenarios" is clear and the references likely complete, and it also highlights the role of clays in storing molecular information, as well as the role of metal sulfides in establishing (maybe) early metabolic reactions:

Let us know what you dig up!


Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?

One model that will help you is the admittedly dated (1981) Preliminary Reference Earth Model. It provides density models for the inner and outer core as functions of distance from the center of the Earth:
$$
\rho =
\begin{cases}
13.0885 - 8.8381 x^2 & \quad \phantom{000}0\phantom{.0} \le r \le 1221.5 \\
12.5815 - 1.2638 x - 3.6426 x^2 - 5.5281 x^3 & \quad 1221.5 \le r \le 3480.0
\end{cases}
$$
where

$\rho$ is the density in grams per cubic centimeter,
$r$ is distance from the center of the Earth to the point of interest in kilometers, and
$x$ is the normalized radius: $x\equiv\frac r {6371}$.

Note that this results in a slight density discontinuity at the boundary between the inner and outer core (1221.5 km). That's intentional. There have been later upgrades to the PREM, but the PREM is where it all starts.

Reference:

Dziewonski, Adam M., and Don L. Anderson. "Preliminary reference Earth model." Physics of the earth and planetary interiors 25.4 (1981): 297-356.


What geology-related displays at museums, universities, etc. in California are especially well-done and enlightening?

Alas, you live in the wrong era. In the 1960s and 1970s by far the best and most informative was the geological museum in South Kensington (West London). Sadly, it is now dumbed-down - sacrificed on the alter of children's populism. The Colorado School of Mines geology museum is reckoned to one of the best, especially for minerals. Otherwise, I can't speak for America, but if you are ever in Vienna you must visit their Natural History Museum where the mineralogy and meteorite galleries are gob-smacking superb. The Natural History Museum in Adelaide, South Australia has the world's best exhibit of Eocambrian fauna, and also boasts a spectacular opalized plesiosaur.


The magnitude of an earthquake is related to the total energy released, therefore to estimate it from a seismogram you need to know the distance to the source. In the case of the Richter scale for example, the relationship between magnitude and seismogram amplitude is defined for a standard distance.

If you have only one seismograph, you can not triangulate the location of the source (hypocenter). Therefore, you can not estimate the magnitude of a seismic event (Richter or moment magnitude).

But you can estimate the local seismic intensity of the event at the particular location of your instrument. With the accelerometer data you can easily measure the peak ground acceleration, that can be used to estimate the intensity in any of the existing scales. For example, the peak ground accelerations associated to each intensity level in the commonly used Mercalli intensity scale are:

Those g values would be easy to calculate with the accelerometer data and proper calibration constants.

Table taken from the Wikipedia page for peak ground acceleration

You might want to have a look at this question. There are some nice answers and references that you might find useful.


What is the difference between mobile & molten rock?

Molten rock must be a liquid, mobile rock is any rock capable of moving, sand and mud can be mobile.


What is the best way to stay safe while photographing lightning storms?

Yes, most storm chasers are risking their lives to take lightning photos. Your likelihood of being struck is obviously higher the closer you are to where lightning is originating from. However, lightning is highly unpredictable, and therefore, there is not much you can do to avoid all odds of being struck. One suggestion would be to take photos from inside your vehicle. You could shoot from the back door of a van or truck with a cap, or set your camera outside and operate it with a remote.

I would advise against being close to tall objects, as although lightning is more likely to strike it than you, you can still experience deadly charge that reaches you through the ground.


Do we know what the rigid mantle looks like?

Above the asthenosphere is the lithosphere. The main constituent of the lower lithosphere is peridotite, a coarse-grained igneous rock containing the minerals olivine and pyroxene. Samples of peridotite can be found in the surface. Sections of ocean crust can be uplifted onto continental margins, forming ophiolites (perhaps the best-known example being the Troodos Ophiolite). They are also found as fragments in basalts and kimberlites, the vertical intrusions that often contain diamonds. So there are lots of places on the surface where you can go and see what the upper mantle looks like! But in the meantime, a closeup of a peridotite is shown below.