The most populous state of the United States faces tremors of magnitude up to 7.4
This area of America has always been considered earthquake-prone, but experts from the US Geological Survey and the Scripps Institute of Oceanography in a recent joint study concluded that the risk of a disaster is higher than previously thought. This work was recently published in the American Journal of Geophysical Research.
The main source of threats to coastal residents is the San Andreas Fault, which is sandwiched between the Pacific and North American plates. It stretches along the Californian coast for 1,300 kilometers. Plate movements lead to large-scale earthquakes, according to seismologists, powerful shocks with a magnitude of 7-8 on the Richter scale occur approximately every 100 years over the past 12 millennia. The last time tectonic processes led to catastrophic consequences in 1906. During the earthquake in San Francisco, layers were displaced by 6-8 meters, this led to the death of about 3,000 people, while the city was 80 percent destroyed. 110 years have passed since then. In 1989, the region shook again: 18 thousand houses fell apart like matchboxes, 18 people died, 3,757 were injured,and the total damage was $ 6 billion. But, according to experts, it was just a warm-up.
The main source of threats to coastal residents is the San Andreas Fault.
To understand how tectonic plates will behave in the near future, seismologists have started mapping the fault using laser rangefinders, ocean bottom seismic station data and other instruments. The study showed that San Andreas is a complex system of four interconnected faults. In this case, a violation of the structure of one of them will cause a chain reaction and provoke powerful tremors. The weak link in this chain turned out to be a rift in the area of Lake Salton Sea. There deformation is the fastest, and earlier these tectonic shifts could not be recorded.
“According to our data, in the area of the fault, the subsoil layers are advancing on each other at a rate of 2.5 centimeters per year,” says the lead author of the study, Valeria Sahakyan, from the University of California, San Diego. - This leads to the accumulation of colossal energy reserves, which will find a way out in a powerful earthquake, when the soil in the fault area moves several meters. We predict that the strength of shocks can reach 7.4 points. The likelihood of such a scenario is 30-40 percent. But even a weaker magnitude 5-6 earthquake could have global consequences, given that the fault lines are no more than 4 kilometers from San Diego and Los Angeles, and the state of California itself is home to 37 million people.
Curiously, two years before this gloomy forecast, the disaster film San Andreas Rift was filmed in Hollywood, which grossed $ 473 million with a budget of $ 110 million. The writers, without hesitation, completely destroyed San Francisco with the help of an earthquake and the ensuing tsunami. Whether this Hollywood "prophecy" will come true - we will find out in the near future.
Promotional video:
Yaroslav KOROBATOV