Can a 99.9% probability of an M≥ 5 earthquake within a 3-year period be verified? Paper:

Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake (2015)

Obviously there has been much discussion on  the viability of earthquake prediction. This recent paper presents some rather bold claims:


  The calculated probability for a M ≥ 6 earthquake within a circle of
  radius 100 km, and over the 3 years following 1 April 2015, is 35%.
  For a M ≥ 5 earthquake within a circle of radius 100 km, and over the
  3 years following 1 April 2015, the probability is 99.9%


On the other hand, the USGS is saying those figures are too high:


  The USGS conducts its own look at quake risk in California — the most
  recent version is called Uniform California Earthquake Rupture
  Forecast, Version 3. Jones said that, according to those models, there is only an 85
  percent chance of a magnitude 5 or 6 quake in the same region over a
  three-year period. "It's nowhere near a 99.9 percent number," Jones said.
  USGS released a statement on its Facebook page saying that the lack of
  details on how this number was reached "makes a critical assessment of
  this approach very difficult."


The LA Times has it reported here: http://touch.latimes.com/#section/-1/article/p2p-84786019/ , which says:


  The study’s lead author, Jet Propulsion Laboratory principal research scientist Andrea Donnellan, said in an interview that the 99.9% figure was not a central conclusion of the paper and should not be viewed as an official forecast.
  “As scientists, we were not putting out an official forecast. We were putting out something in a paper to test,” Donnellan said.
  Donnellan said she considers the 99.9% number a test of a model, or algorithm, on the probability of future earthquakes. 
  “We never said in this paper we were predicting an earthquake. And we said that's the probability of an event," Donnellan said. "There is still a 0.1% chance it won't happen. So we need to test it. And that's what we are doing as scientists."


Has anyone verified this study? Is there anything wrong with it? How were they able to arrive at such a high probability?
Based on Probabilistic Seismic Hazard Analysis the probability of an earthquake of magnitude $m$ occurring at the source is obtained with the Truncated Exponential Distribution can be given by 

$$P(M &gt; m) = \int_{m}^{m_{max}} \frac{\beta e^{-\beta (m - m_{min})}}{\left( 1 - e^{-\beta (m_{max} - m_{min})} \right)}dm$$

where :

$m$ is the magnitude; $m_{min}$ is the minimum magnitude of earthquakes in source; $m_{max}$ is the maximum magnitude of earthquakes in source; $P(M &gt; m)$ is the probability of occurrence of an earthquake with magnitude $M$ larger than $m$; $\beta = b \ln(10)$; $b$ is the slope in the Gutenberg–Richter (G–R) magnitude–frequency relation.

Source : Development of probabilistic seismic hazard analysis for international sites, challenges and guidelines

Additional Read : Gutenberg Richter Law - why exponential distribution was used