“I think this paper does a good job representing the uncertainties.”ĭr. In studying earthquakes, he added, “ ‘What’s next’ is a really tough problem for us. “But just because we can create a plausible scenario does not mean it’s going to happen,” Dr.
“I wouldn’t challenge the notion that the Garlock could have a larger event.” “I wouldn’t call it far-fetched,” he said. Kenneth Hudnut, another geological survey geophysicist who studied an earthquake sequence that occurred in the Imperial Valley of California in 1987, said the chain of events suggested in the new study was just one of many plausible scenarios for what could happen in Southern California. “It’s possible, but in terms of something to worry about, it’s a low probability.” “It’s kind of a Rube Goldberg scenario,” she said. Susan Hough, a research seismologist with the geological survey, said she thought such a chain of events was unlikely. “If it comes within about 25 miles of the San Andreas, it increases the chances of an earthquake there by about 150 times.” “The Garlock is the link in the chain,” Dr. The Garlock is perpendicular to it, and the researchers found that a major quake on the Garlock had the potential to set off one on the San Andreas, if the Garlock rupture came near the bigger fault. Of far greater concern is the San Andreas, the major fault that runs from northern to Southern California. They said there was a 2.3 percent chance of a Garlock quake over the next year.īut the Garlock runs through a relatively unpopulated area. In their analysis, they showed that the Ridgecrest quakes changed stresses along a nearby fault, the Garlock, and increased the possibility of a major quake on a 75-mile length of it. But in general these kinds of stress changes are temporary the likelihood of another quake decreases over time. The quakes, of magnitudes 6.4 and 7.1, resulted in one death, about two dozen injuries and at least $1 billion in damage.Īt Ridgecrest, the changes from the first earthquake triggered the second 34 hours later. Stein and a longtime collaborator, Shinji Toda of Tohoku University in Japan modeled changes in stresses in the complex structure of surrounding faults that resulted from the two 2019 quakes, which occurred in sequence near Ridgecrest, Calif., about 120 miles north of Los Angeles. Currently the geological survey forecasts a 31 percent probability of a 7.5-magnitude quake occurring in the Los Angeles area in the next 30 years.ĭr. Page, a research geophysicist who works on earthquake forecasting at the geological survey, said that while she agreed with the basic premise of the study, “their numbers are too high.”Įarthquake forecasts describe the likelihood of a quake occurring over a given time period they are not predictions of a specific event at a specific time. The findings were published in the Bulletin of the Seismological Society of America.īut other researchers took issue with the analysis, saying it overstated the probability.
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