The Ring of Fire around the Pacific Ocean has experienced eight earthquakes that were magnitude 6.5 or higher over a period of three weeks. Credit: USGS
In August is shaping up to be a pretty eventful month, thanks to a number of major earthquakes all over the world. These earthquakes have led to reports that California is a greater chance of a catastrophic earthquake, popularly known as “the big one” very soon. But experts say that’s not how earthquakes work.
In the past three weeks, there are eight quakes that were magnitude 6.5 or higher. That is 40 percent of the large quakes that have happened so far this year, according to the u.s. Geological Survey (USGS). Yesterday morning (Aug. 22), a magnitude-6.2 earthquake struck about 170 miles (273 kilometers off the coast of Oregon, along the Blank Fractal Zone (los of the San Andreas Fault in California), USGS reported.
But don’t worry — the occurrence of these earthquakes does not suggest that there is a higher chance now, as compared with other times, that California is a major earthquake.
“I have not heard of a seismologists who fear that California is now the big one,'” said Jascha Polet, a seismologist at the California State Polytechnic University Pomona. “In the past few days, there are more large earthquakes (worldwide) than average, but that will happen in a random distribution,” Polet told Science in an e-mail. [The 10 Biggest Earthquakes in History]
Seven of this month to eight sample shakers in the Ring of Fire, or the Circum-Pacific Belt. This region is the horseshoe-shaped edge of the Pacific Ocean, where about 90 percent of the world’s earthquakes occur, according to the USGS. California is included on the eastern side of the ring, and so far, the state has been spared major earthquake activity in the past few months. In the past 30 days, the largest quake was a magnitude of 4.5, which occurred July 25, 65 miles (105 km) off the coast of northern California.
But there are regions, such as the Ring of Fire, which are more prone to seismic activity than others, earthquakes are discrete events that occur randomly and independently of each other over time. The recent increase of seismic activity after an apparent silence is exactly what seismologists expect. “In a random distribution, there will be periods of low and high activity,” Polet said.
Earthquakes can shift the underlying stress on that particular fault, which, in turn, may increase the chance of later quakes in the area around the error. For example, large earthquakes typically result in aftershocks, or smaller earthquakes in the same area of the earthquake. “These aftershocks will decrease in size and frequency as time progresses and the guilt settles in,” said Kasey Aderhold, a seismologist with the Survey Included Institutions for Seismology, a non-profit research organisation. “The bigger the disaster, the longer it takes to settle back down to the usual background of seismic activity,” she said. Aderhold also explained that the biggest earthquakes, like the magnitude-9.1 Tohoku earthquake off the coast of Japan will have aftershocks for the next few years.
California has a history of experiencing great earthquakes such as the magnitude 7.8 earthquake that rocked San Francisco in 1906, the magnitude-6.9 Loma Prieta earthquake in 1989, that the cause of 63 people dead and thousands injured, according to the USGS. Because many years have passed without a major earthquake in California, some news media have speculated that the chance that a devastating earthquake occurs in California is higher now, given the recent increase in earthquake events around the Ring of Fire.
“We have other large earthquakes that do not lead to the ‘big one’, the Aderhold told Science in an e-mail. For example, she said, “the 2004 [size] 9.2 Sumatra earthquake made anywhere on Earth-and that with at least 1 inch [2.5 inch],” but there was no west coast “big one.” Aderhold also noted the 2011 magnitude-9.1 Tohoku earthquake off the coast of Japan and the 2017 magnitude-8.2 Chiapas, Mexico, earthquake, neither of which came a great earthquake in California.
According to the USGS, the southern California area experiences approximately 10,000 earthquakes per year although most are so small, that the people do not even feel. But this does not mean that Californians should be prepared for the more destructive earthquakes.
The USGS predicts that in the next 30 years, the probability of at least one magnitude-6.7 or higher earthquake is 60 percent in the area of Los Angeles and 72 percent in the San Francisco Bay area.
“The bottom line is that a large and potentially damaging earthquake will occur in California and other places in the world, and the communities should continue to review and improve their preparations and plans,” Aderhold said. “Large earthquakes elsewhere are a good reminder.”
The USGS recommends that apart from emergency assistance, such as a first aid kit, medications and a fire extinguisher. You can find the complete list of articles, and other helpful tips for earthquake preparedness, on the USGS website.
Original article on Live Science.