A California fault capable of producing devastating earthquakes is moving for the first time on record.
In a new study published on Thursday in the journal Science, Caltech scientists alongside NASA's Jet Propulsion Laboratory found that a portion of the 160-mile long Garlock fault, which runs on the northern edge of the Mojave Desert, shifted after a sequence of earthquakes in the nearby Ridgecrest area in California disturbed it. According to the scientists, the Garlock fault has slipped two centimetres at the surface since July.
The Garlock fault is in a precarious location that makes it capable of producing magnitude 8 quakes. If Garlock starts quaking, it could shake nearby oil and agriculture regions in California, as well as military bases, the Los Angeles Times notes.
The researchers used seismometer data and satellite observations to document the earthquake sequence and the Garlock fault’s creep. The bulge in the land caused by the fault was visible from space.
“This is surprising, because we’ve never seen the Garlock fault do anything. Here, all of a sudden, it changed its behavior,” Zachary Ross, the lead author of the study and assistant professor of geophysics at Caltech, told the Los Angeles Times. “We don’t know what it means.”
The finding further destabilizes a myth that smaller earthquakes prevent the Big One from happening. In fact, it supports the opposite conclusion: that localized quakes can disrupt faults, creating more risk for bigger quakes along them.
A quake that hits 8 on the Richter scale could be catastrophic. The 1985 earthquake that devastated Mexico City was an 8, and it caused widespread destruction. But gathering more information about how and why big quakes occur could help predict the next one before it happens.