Earthquake Experts: We Live ‘In Earthquake Country’

The 6.0 magnitude Napa earthquake, which was responsible for $400 million in damages, 200 injuries, and one death last August, had people asking questions about how safe they truly are in the face of an unexpected calamity. The western United States, a region covered by the Pacific ring of fire, is naturally susceptible to earthquakes. However, most people do not consider themselves ready enough to face the immediate dangers of these types of unforeseen events.

Two earthquake experts recently visited Reddit to answer some of the most pressing questions about earthquakes, the scientific mechanisms that drive them, and how Americans can prepare themselves in the face of such calamities. Dr. Robert Muir-Wood and Dr. Patricia Grossi are two earthquake experts who work for the world-leading catatstrophe modeling firm, RMS. Here are some of the questions they answered.

Redditor drummer9 asked, “I live in the Bay Area and since the Napa quake that happened recently I have stocked up on emergency supplies and have a disaster plan. Is my paranoia founded, and how do you expect the next Bay Area earthquake to affect the region?”

Dr. Grossi answered,

“The Napa earthquake was a good reminder to everyone who lives in the San Francisco Bay area that we live “in earthquake country”. We should all be preparing to be on our own (without water, power, etc) for the first 72 hours. Good planning for disasters is important – not paranoia. As for earthquake risk to the larger bay area region – there are seven major fault zones that bisect the region – San Andreas, Hayward, Calaveras, Concord-Green Valley, Greeneville, Rodgers Creek, San Gregorio – with the largest probabilities of rupture along the San Andreas and Hayward faults. If the Hayward fault ruptures, it will be felt again in Napa county.”

Redditor Sutisi asked, “I have always wondered… have you noticed an increase or decrease in severe earthquakes in the time since accurate measurements could be recorded?”

Dr. Muir-Wood answered,

“The level of activity stays much the same (but people may tend to only remember the earthquakes of the past couple of years). However there was a strange gap in the activity of the largest of all giant earthquakes worldwide above Mw8.5 from 1965 until 2004, and then at least four such earthquakes since 2004.”

CampBenCh asked, “I know parts of Missouri can have serious earthquakes. Could that part of the country experience a 7.0 quake? Would you consider a large quake in that area to be more dangerous since people don’t often think of that area being seismically active?”

R. Muir-Wood answered,

“Earthquakes are definitely more dangerous where people do not give them any attention. In California most houses are built of wood, and do quite well in earthquakes. In places where houses are built of brick one can expect many more casualties. However an M7 earthquake in Missouri is quite low probability”

Read the rest of the Reddit AMA here. For more information on earthquake preparedness, read this article from the Red Cross here.