Egill Hauksson, a geophysicist at the California Institute of Technology, said the rate of quakes in the region was ”probably … picking up again” after a relative lull that lasted more than 10 years.
”What it means is that we are going to have more earthquakes than in the average year. With more earthquakes, we’re bound to have more bigger ones. But there are always fewer of those than the smaller ones.”
Scientists, however, have not been able to identify reasons that fully explain the increase.
Many of the earthquakes this year have been aftershocks to a 7.2 temblor that rattled the Mexicali area earlier this month. The border region had experienced smaller quakes before the big one. And there have been more than 1000 aftershocks, including more than a dozen that registered higher than 5.0.
The Mexicali quake was the region’s largest since one of 7.3 in the Mojave Desert in 1992. Despite their size, neither quake did catastrophic damage because they occurred in relatively remote areas far from large population centres.
In California, scientists say one of their biggest concerns remains the San Andreas fault, which has produced some of the state’s largest earthquakes. Experts have said the San Andreas is overdue for an eruption. State officials have also often noted that only about one in six Californians has earthquake insurance.
Los Angeles Times