Could an 8.2 Magnitude Earthquake Devastate California?

Californians are used to the threat of earthquakes, but Thursday’s massive earthquake that devastated Mexico leaves many questioning what would happen if a similarly powerful earthquake were to happen near Los Angeles.

At least 61 people in Mexico were killed by Thursday’s 8.2 magnitude earthquake.. The earthquake’s epicenter in Pijijiapan, near the Guatamala border, was Mexico’s largest in nearly a century.

ABC News reports:

Pena Nieto said authorities were working to re-establish supplies of water and food and provide medical attention to those who need it. He vowed the government would help rebuild.

“The power of this earthquake was devastating, but we are certain that the power of unity, the power of solidarity and the power of shared responsibility will be greater,” Pena Nieto said.

Power was cut at least briefly to more than 1.8 million people, and authorities closed schools in at least 11 states to check them for safety.

The Interior Department reported that 428 homes were destroyed and 1,700 were damaged just in Chiapas, the state closest to the epicenter.

A similar 8.2 earthquake with an epicenter at California’s Salton Sea would travel north along the San Andreas fault into central California, causing massive devastation along the way.

The fault is a mere 30 miles from downtown Los Angeles.

Mexico’s recent 8.2 magnitude earthquake’s epicenter was deep under the ocean, effecting a small part of the country that was far less populated than at risk regions in California.

A massive Californian earthquake could devastate several counties after a rupture of the San Andreas fault.

The LA Times reports:

A magnitude 8.2 earthquake would rupture the San Andreas fault from the Salton Sea — close to the Mexican border — all the way to Monterey County. The fault would rupture through counties including Los Angeles, Riverside and San Bernardino.

An 8.2 earthquake would be far worse here because the San Andreas fault runs right through areas such as the Coachella Valley — home to Palm Springs — and the San Bernardino Valley, along with the San Gabriel Mountains north of Los Angeles. The fault is about 30 miles from downtown Los Angeles.

Thursday’s earthquake occurred in the ocean off the Mexican coast and began about 450 miles from Mexico City — and it was relatively deep, starting about 43 miles under the surface.

[…] A magnitude 8.2 earthquake on the San Andreas would produce shaking more intense than either the Mexico or Northridge earthquakes.

It would bring intensity level 10 shaking, which is perceived by humans as “extreme.” Such shaking would blanket huge swaths of Southern California — an earthquake that no one alive today has experienced in this region.

According to a U.S. Geological Survey, even a 7.8 earthquake on the San Andreas Fault would be expected to have a death toll of around 1,800 people, with Los Angeles county suffering the most loss of life.

The survey’s ShakeOut Scenario estimates massive, widespread damage:

Because of these mitigation measures, the total financial impact of this earthquake is estimated to be “only” about $200 billion with approximately 1,800 fatalities. These are still big numbers.

[…] The earthquake causes the ignition of 1,600 fires. Owing in part to the loss of piped water for firefighting, 200 million sq ft of residential and commercial property valued at $40-100 billion is burnt. This is in addition to shaking-related property and direct income losses valued at approximately $60 billion. Five pre-Northridge highrise steel moment-frame buildings completely collapse, with approximately 5,000 people inside. Approximately 50 low- and midrise older reinforced concrete moment-frame buildings are hypothesized to collapse, most partially, as opposed to complete pancakestyle collapse. These involve 800 people in completely collapsed concrete buildings and 7,000 in partially collapsed ones. Approximately 900 unreinforced masonry buildings are irreparably damaged.

Is California prepared to deal with the ShakeOut scenario?

Should an even worse 8.2 magnitude earthquake rupture the San Andreas Fault, it could be the worst natural disasters the country has ever seen.