Geophysics Research Opportunities

Our research groups focus on understanding fundamental, physical processes
occurring within the Earth’s mantle and lithosphere and on its surface. We
study a wide variety of problems on many spatial and temporal scales, ranging from
mantle upwelling to glacial dynamics. A list of research interests
can be found under the About Us menu item. A few
of the research questions that our faculty and students address include:

What is the magnitude of forces that push on continents?

What are the forces that reorganize oceanic plate boundaries?

What are the pathways by which magma reaches volcanos at mid-ocean ridges,
hotspots and arcs?

What are the processes that make some faults weak?

What controls how glaciers slide and produce erosion?

How are mid-ocean ridges and hotspots related to global mantle flow?

Current Projects

Listed below are a few of the active projects within the department that
address some of the scientific questions posed above. Financial support,
often provided by the National Science Foundation, is provided for qualified
graduate students.

The Mechanics of Slow Earthquakes and Fault Creep

Slow earthquakes are a special type of faulting where the slip rate is significantly
lower than that observed during an earthquake. Observations over the
past decade suggest that these events are more prevalent than previously
appreciated. We are using satellite observations to document slow slip
on major strike-slip faults across the planet. This project aims to
strengthen the relationship between the known theoretical mechanisms for
slow slip and the observed properties of the fault. For more information
on this project, contact Prof. Schmidt.

Dynamic Weakening and Melting During Seismic Slip

Large reductions in fault strength can occur during earthquakes as a consequence
of the rapid heating that results from mechanical work. In extreme cases,
the temperature rise is expected to be sufficient to cause melting. However,
despite the enormous quantities of energy that are released during large
earthquakes along mature fault surfaces (those faults that have accommodated
many km's of slip and are distinguished by zones consisting of highly granulated
gouge particles), evidence for melting is encountered only rarely. Current
research by Prof. Rempel and his group is focused
on understanding how fault strength evolves near the melting transition and
whether melt onset itself might be self-regulating and impede subsequent
temperature rise.

Glacier Sliding and Sediment Transport

Glaciers slide over thin melt layers that separate the ice from the underlying
bedrock and sediments. The resistance to sliding and the incorporation
of sediments into basal ice are both linked to the pressure distribution
in these melt layers and the pore waters beneath. Research by Prof.
Rempel and his group is focused on developing quantitative,
predictive models that incorporate a modern understanding of the microphysics
of melting and the controls on pore water pressure into descriptions of glacier
sliding and sediment transport.

Oceanic Hotspot - Ridge Interaction and Changes with Time

Ocean hotspots and ridges are two fundamentally different modes of magmatism
on Earth; where they are close together they interact. The Reykjanes ridge,
south of Iceland, is one of the most prominent examples of this interaction
and also reveals striking changes of time. Prof. Hooft will
be collecting seismic data in order to use crustal thickness and velocities
in combination with basalt compositions from ocean drilling to understand
the depth and mechanisms of hotspot-ridge interactions and what causes these
vary temporally.

Mid-ocean Ridges and Interlinked Systems

Mid-ocean ridges are a primary site of mass and energy exchange between
Earth’s mantle and hydrosphere and atmosphere. Prof.
Toomey and Prof.
Hooft will be going to sea in the next year to study these
feedback processes at the Endeavour segment of the Juan de Fuca ridge. We
will tomographically image the magma plumbing system in the mantle and crust
and the thermal boundary layer that transports energy between the magmatic
and hydrothermal systems. Our experiment will: (1) Determine if the
segmentation and intensity of the magma-hydrothermal systems at the Endeavour
ridge are related to magma supply or to the magma plumbing between the mantle
and crust, and (2) Constrain the thermal and magmatic structure underlying
the Endeavour hydrothermal system in order to understand the patterns of
energy transfer.