Bad news first. Humans probably caused some of the worst earthquakes in Los Angeles history as a direct result of our thirst for fossil fuels. But here's the good news: now that scientists know that, they're looking at totally different stats for the future of the region's seismic stability.
Practices used by the oil and gas industry around the beginning of the 20th century probably contributed to the serious shakers that hit in 1920, 1929, 1930 and 1933. The 1933 quake hit Long Beach at a 6.4 magnitude, which would be considered significant even with today’s updated construction standards and infrastructure. For comparison, a 6.7 quake hit L.A. in 1994 and caused $13 to $40 billion dollars in damage as a result, so you can imagine how devastating it might have been decades prior.
Gizmodo reports that the findings published in the Bulletin of the Seismological Society of America link the quakes to the oil boom that hit L.A. starting in 1892. Back in the roaring '20s, the city had enough oil fields that we were pumping out almost 20 percent of the entire global supply of crude oil. The U.S. Geological Survey scientists who worked on the report found that the number, locations and depths of the wells correlated strongly to the epicenters of earthquakes.
Here’s why this is particularly exciting for seismologists: this fact could mean that the L.A. Basin region is significantly less susceptible to naturally-occurring earthquakes than previously suspected. Because, if scientists are pretty sure those four big earthquakes were caused by human practices that we’ve stopped doing, they might be able to take them out of the data set when it comes to making predictions.
Even still, those findings, if they hold up, will be limited to the Los Angeles Basin tectonic region itself, so it is still important to be prepared for serious earthquakes to come. The Salton Sea region, a major hotspot for fault activity that sits outside the basin, has been rumbling lately, with at least 20 micro-quakes very similar to the ones that caused an elevated quake warning mere weeks ago. So like we said, still probably best to keep that earthquake kit around.
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