Well, that is not exactly what they say – but it is close. Using data from before and after the 2014 M 5.1 La Habra earthquake, NASA developed a model of the main and surrounding shocks. GPS and Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) measurements showed “a broad pattern of deformation that would be expected of a M5.1 earthquake.” (tinyurl.com/putd88o) The six modeled “structures and slips” account for the estimated seismic moment, that is a measure of the amount of earth movement due to the quake. The authors stated that their modeled “results are consistent with north-south shortening and westward escape of the crust near Los Angeles.” Guess we continue the “go west, young man” (and woman) adventure.
NASA continued the analysis by looking at the Gutenburg-Richter relation for earthquakes in the region from 1994 to 2015 and estimated that there is a 99.9% probability that another greater than 5 magnitude earthquake will hit before April 1, 2018. The probability that it will be greater than 6 is much less at 35%. But, still. All of this for an area within 100 km (60 miles) of the La Habra epicenter (Figure 1), which covers most of the greater Los Angeles area. The rational behind the estimate is that more pent up energy is buried deep and the 2014 shake left it unreleased.
Figure 1. 100 km radius around La Habra, CA.
This is not the first, and certainly won’t be the last, prediction of a big earthquake in Southern California. The USGS gives a 85% probability for the >5 M earthquake, for instance. More on that later.