1/15/2024 0 Comments Ca quake mapSuch a quake could kill more than 200 people and destroy more than 2,000 buildings. But the USGS has studied the implications of a less powerful, magnitude 7.3 quake there, and it could still be destructive. Scientists haven’t fully explored the ramifications of a magnitude 7.8 quake on the Palos Verdes fault zone. The area most recently has generated quakes of magnitude 2 to 3, barely enough to be felt by most people. In contrast, the Palos Verdes fault zone has not produced a big earthquake during the same time period. But the gap between quakes can vary: Over a 1,000-year period, there was once a gap of 20 years between major quakes and once a gap of 200 years. On one section of the San Andreas fault along the Grapevine, scientists have found evidence that major earthquakes happen there on average every 100 years. Seismologists estimate the southern San Andreas fault is capable of a magnitude 8.2 earthquake. The last time Southern California was struck by a quake as powerful as a magnitude 7.8 was in 1857, when the San Andreas fault ruptured from Monterey County through the San Gabriel Mountains north of Los Angeles and into the Cajon Pass. Scientists have likened it to someone driving at unsafe speeds - those are the ones most likely to get into a collision. Such a massive earthquake occurring in our lifetime is especially plausible because the San Andreas is the fastest-moving fault in the state, slipping at a rate of 15 to 35 millimeters a year. Vulnerable pipelines carrying fuel and natural gas and overhead electricity lines through the Cajon Pass in San Bernardino County could explode, threatening the power grid. Under the simulation’s scenario, freeways linking the region to Las Vegas and Phoenix could be destroyed, as could the aqueducts that bring in most of L.A. County, could cause 1,800 deaths, with hundreds killed in building collapses, according to a simulation of such a temblor released by the USGS in 2008. The effects of a magnitude 7.8 earthquake - which would be 45 times stronger than the Northridge quake - depend on the fault’s location.Ī quake of that magnitude on the southern San Andreas fault, rupturing between the Salton Sea near the Mexico border and passing through Palm Springs and into Lake Hughes, north of Santa Clarita in L.A. Here’s a basic primer on the science of earthquakes. Earlier estimates said the fault zone could generate up to a magnitude 7.4 earthquake, but the new study shows it could produce a quake as strong as 7.8.Ĭalifornia How earthquakes happen: The science of a shakeīefore we can prepare for the Big One, we have to know what “one” is. Scientists found the fault could produce a quake of a magnitude comparable to one from the San Andreas fault. The analysis determined the fault system, which runs beneath numerous neighborhoods as well as the ports of Long Beach and L.A., has a much larger surface area that could rupture in the same seismic event, making it capable of a far more powerful quake than was previously known. It previously was thought to be a segmented network of smaller faults, but a closer look by scientists at Harvard University suggests it’s a system of interconnected, closely spaced planar fractures stretching from the Santa Monica Bay to the waters off Dana Point. Known as the Palos Verdes fault zone, the system runs deep beneath the Palos Verdes Peninsula. A fault system running nearly 70 miles along the coast of Los Angeles and Orange counties has the potential to trigger a magnitude 7.8 earthquake, according to a new study that is the latest to highlight the seismic threats facing Southern California.
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