The large earthquake that hit southern California during the summer has increased the load on a major fault nearby, causing it to move for the first time, researchers said on Thursday.
Crash in the July earthquake sequence in Ridgecrest ended a few miles from the Garlock fault, which runs east-west for 300 miles from the San Andreas fault to Death Valley. This error has been relatively quiet for 500 years, but has now begun to slowly creep, according to a new study released in the journal Science.
"It's surprising," Zachary Ross, assistant professor of geophysics at Caltech and principal author of paper, said. “In California, we have been monitoring earthquakes for a long time. We think we have a pretty good sense of what is typical behavior over long time scales … and when something anomalous happens, it obviously stands out.
"We just don't know what this might mean," he added. 19659002] The Ridgecrest earthquake sequence was the largest in two decades in Southern California and began July 4 in the Mojave Desert about 190 miles north of Los Angeles. After a pre-shock with a strength of 6.4, there was a headstock of size 7.1 the next day, followed by more than 100,000 aftershocks.
The Garlock fault is capable of producing an earthquake of magnitude 8 and has been 0.8in (2 cm)) since July found the study of geophysicists from California Institute of Technology and Nasa Jet Propulsion Laboratory. It was over a sufficiently long length of error that radar satellites in space detected it, Ross said.
"We have never seen this mistake before," Ross said, emphasizing that it was impossible to speculate what the move might mean for future dangers.
The study also found that the Ridgecrest sequence involved breaking a web of interconnected errors. The researchers noted that although large earthquakes are usually believed to be caused by fractures by a single long fault, seismologists have since thought about that model.
The Ridgecrest sequence involved about 20 previously undetected faults that crossed, providing another example of how large earthquakes can be generated by a network-like network of smaller "faults that, when they burst, trigger each other as falling dominoes," the authors said.
This means that seismologists may have to think about how they quantify potential hazards and define moving forward faults, Ross said: "It inject much more uncertainty … It is difficult to come up with all sorts of possible scenarios where small faults are activated together to produce any event … There are an infinite number of combinations. "
The study was published on the 30th anniversary of the lethal 6.9 Loma Prieta earthquake that damaged the San Francisco Bay Area and the same day tha t California implemented an early earthquake state earthquake system for the public.
Warning signals were previously made available to schools, government agencies, industries and industries but not the public, except in Los Angeles County, where an app-based system has been in use since January.