NASA is warning Los Angeles-area residents to get ready: the agency says an earthquake of at least a magnitude 5.0 is a 99% certainty within the next 30 months.
Andrea Donnellan, a seismologist with NASA’s Jet Propulsion Laboratory, and colleagues arrived at the estimate based on data from a study conducted of the Puente Hills and Whittier faults, both of which were responsible for the 5.1 La Habra quake in March 2014. 
A 5.0 quake is certainly powerful enough to do damage, but there is also a terrifying 35% chance that Los Angeles could see a quake measuring at least 6.0. Donnellan says there is enough energy stored along the faults to produce a quake of a magnitude 6.1 to 6.3. 
Regardless of size, the quake could occur anywhere within 100 kilometers – about 60 miles – of the 2014 quake. This is why we offer a number of essential preparedness items everyone should have in their home.
The ground underneath California is constantly moving, but the earth has been especially active in the past week, as more than 200 small quakes have rattled San Ramon in the Bay Area in northern California since Monday.
Richard Allen, the director of UC Berkeley’s Seismology Laboratory, doesn’t believe the quakes are related because they occurred along different fault lines. The possibility can’t be ruled out, however; according to Wired, it’s possible that the energy released by one of the quakes was great enough to impact its neighboring faults. Allen says this isn’t plausible because the quakes weren’t strong enough.
But there’s no way to predict where the stress from a seismological event will transfer, or if it will at all. The bedrock beneath California may absorb some of the shaking, Wired reports, but some of the waves from a quake roll through the sandy soil nestled beside bodies of water like the bay.
Seismologists generally agree that the swarm – or non-swarm – isn’t particularly shocking and is no reason for concern, but it illustrates the constant fluid motion of land in that state.
Near Los Angeles, the last time the Puente Hills fault roared to life in a significant way was in 1987, when a 5.9 quake killed 3 people.
U.S. Geological Survey seismologists (USGS) say Donnellan and her team’s estimate may be a bit high, stating: “…the accepted random chance of a (magnitude five) or greater in this area in three years is 85 percent, independent of the analysis in this paper.”
The USGS has warned there is a 7% chance that an 8.0-magnitude quake will occur in the area within the next 30 years. 
Donnellan’s study was published earlier this month, and a revised version is due to be released soon. The Los Angeles Daily News reports that the study’s full findings will be released within the next couple of days.
 CBS Los Angeles
 Daily Democrat