Scientists at Caltech issued a warning this week that a large California fault that could cause a magnitude 8 earthquake has detected a move for the first time.
In modern historical records, the more than 250-kilometer-long Gallock fault located on the northern edge of the Mojave Desert has never been observed with strong earthquakes or creeps. The study, published in the journal science this Thursday, was jointly completed by top experts in the field of seismic science at the California Institute of Technology and the California Institute of Technology in the Jet Propulsion Laboratory in Latin Canada.
Now new satellite radar images show that the fault has begun to move, and obvious land uplifts can be seen from space. The creeping part of the Garlock fault is about 32 kilometers long, with land on the north side of the fault moving westward while the other side moving eastward. Radar images show that one side of the tomography moves at a maximum amplitude of about 2 cm relative to the other side.
This incident surprised seismologists because I had never seen such a thing happen to the Gallock fault before. Now suddenly, the fault changes its behavior pattern, seismologists are confused, and it is not possible to determine what such a movement means. The occurrence of creep indicates that the largest Ridgecrest earthquake in Southern California in 20 years has devastated the stability of remote desert areas between California’s largest mountain range, Sierra Nevada and its lowest point, Death Valley . It also exposes a long-standing lie in California and elsewhere: Earthquakes like Ridgecrest are somehow a good thing to reduce the likelihood of future earthquakes. In fact, these earthquakes make the future more likely to occur. Although most of the time, subsequent earthquakes are relatively small, sometimes they are bigger.
Not only did the Gallock fault start to creep in a certain area, but a large number of small earthquakes also occurred in other parts of the fault. Two other cluster earthquakes occurred elsewhere, one south of Lake Owens and the other west of the Panamment Valley.
Whether the instability of the fault will quickly lead to large earthquakes unpredictable. The most likely scenario is that the Ridgecrest earthquake may not trigger a larger earthquake, the U.S. Geological Survey said. Still, they said the July earthquake increased the likelihood of earthquakes above magnitude 7.5 in the nearby Garlock, Owens Valley, Blackwater and Panamment Valley faults. The major earthquake in the Gallock fault could cause strong shocks to the San Fernando Valley, Santa Clarita, Lancaster , Parmdale, Ventura, Oxnard, Bakersfield and Kern counties, which are one of the highest agricultural and oil production in the United States.
A large earthquake that occurred in the Garlock fault may in turn destabilize San Andreas. The San Andreas fault in southern California stretches about 480 kilometers. If a strong earthquake occurs, it may cause the worst shock in southern California since 1857 and have a devastating impact on Los Angeles and surrounding areas. The peristaltic fault caused by nearby earthquakes does not necessarily mean that a major earthquake is about to occur.
is worth noting, and the Garlock fault has been calm in history so far. While it is unclear what creeping and aftershocks may mean in the near future, the newly observed movement highlights how much potential risks are to California if a large-scale fracture occurs in the Gallock fault.
The cumulative seismic strain velocity of the Gallock fault ranks among the top in California. According to Morgan Page, a geophysicist at the U.S. Geophysicist at the U.S. Geological Survey , the average interval between earthquakes at least magnitude 7 and above in the center of the fault is about every 1,200 years. But sometimes the next major earthquake will occur only 200 years apart from the two major earthquakes on the faults. The last major earthquake is believed to have occurred about 465 years ago. When will the next time happen? No one dares to assert. (Reference for this article: Los Angeles Times)