Scientists at NASA's Jet Propulsion Laboratory shocked the seismic community when they published a study that says there is a 99% chance a magnitude 5 or larger earthquake will hit the LA area in the next three years.
In a recently published study, scientists used radar and GPS to measure the probability of future earthquakes. The study found that the earthquake that struck the La Habra area in the spring of 2014 had more surface deformation than a typical 5.1 magnitude earthquake should. "The shallow ground movements observed from this earthquake likely reflect strain accumulated on deeper faults, which remain locked and may be capable of producing future earthquakes," says the study.
“When the La Habra earthquake happened, it was relieving some of that stress, and it actually shook some of the upper sediments in the LA basin and moved those a little bit more,” Dr. Donellan said to CBS Los Angeles. “There’s enough energy stored to produce about a magnitude 6.1 to 6.3 earthquake [in the same epicenter in La Habra]."
Dr. Donellan and her team went on to measure the probability of a similar quake hitting the Los Angeles area under their model and arrived at 99 percent. While bold predictions are not new to the community, it is the certainty that has people shocked and skeptical.
The U.S. Geological Survey took their Facebook page with a statement regarding the JPL study. In it they say that the study does not provide a clear description of how the 99 percent numbers were reached and that the accepted number is 85 percent. The accepted number is reached through "the community developed and accepted model of earthquake occurrence, "UCERF3", which is the basis of the USGS National Seismic Hazard Maps."
The USGS goes on to say that although the piece has been published, it has not been examined by the established committees that evaluate earthquake forecasts and predictions made by scientists.
"The earthquake rate implied by the 99.9% probability is significantly higher than observed at any time previously in Southern California, and the lack of details on the method of analysis makes a critical assessment of this approach very difficult. Therefore, the USGS does not consider the analysis presented in this paper a reason to change our assessment of the hazard." -USGS Statement