CALIFORNIA JOLTED BY 3 EARTHQUAKES WITHIN MINUTES. IS THE ‘BIG ONE’ COMING?

Wed 29 March 2023:

Three earthquakes shook California early on Tuesday, frightening the residents as they battled the aftermath of a recent winter storm. The quakes weren’t particularly strong, but three of them in the space of three minutes terrified the locals. The first earthquake, which occurred at 6:01 am and had a magnitude of 3.5, was reported by the US Geological Survey. Then, two magnitude 2.6 aftershocks occurred. Both the first and second aftershocks occurred at 6:03 and 6:04 in the morning.

No injuries nor damage were reported. The tremors were felt by people from Santa Cruz to San Francisco.

The Bay Area has been struggling to overcome the aftermath of a series of storms that have inundated several areas and forced residents to take shelter in evacuation centers.

The San Andreas Fault

Even though the magnitude of the quakes wasn’t as high, the fact that California sits on a seismic zone that is similar to the one in Turkey and Syria raises concerns. While the quake hit the East Anatolian Fault in Turkey, California sits on the San Andreas. Following the massive quake in Turkey and Syria, people began to wonder if the next “big one” will hit California. The two faults have similar patterns — with one long, major fault and several smaller, secondary ones.

San Andreas is an 800-mile-long fault covering California from north to south. However, the Turkish fault is only about half as long as San Andreas, and a secondary fault line, but still managed to cause such a huge scale of devastation. This leads experts to worry, what if a similar quake strikes California on a secondary fault line?

Given that the southern San Andreas is one of the regions that is overdue for an earthquake of greater than magnitude 7.5, experts say it appears to be a danger zone. Areas like San Bernardino, Palm Springs, and Imperial County would suffer severe destruction in that case. According to geological surveys, Los Angeles has a 30% chance of experiencing a 7.5-magnitude earthquake within the next 30 years. Similarly, there is a 20% chance that the same thing will occur in the San Francisco Bay Area.

The southern San Andreas fault hasn’t had a big earthquake since around 1690, which makes it even more susceptible to a “big one”. In 2008, a study estimated that a 7.8 magnitude earthquake in this region could kill 1,800 people.

Two “big ones” have so far occurred in California: the first in 1857, which hit the northern third of the San Andreas, and the second in 1906, which hit the central third. Despite being under 8.0 in magnitude, the two quakes managed to significantly damage both property and lives.

According to experts, the term “big one” does not always refer to earthquakes with magnitudes right and above. Both the 1989 earthquake in the San Francisco area and the 1994 earthquake in Northridge were under seven but still did a lot of damage.