800 miles long, stretching from city to city across the coast of California, the looming threat of the San Andreas fault is one I’m sure most Angelenos are familiar with. Whenever LA is hit with another minor earthquake, the phrase “We’re overdue” is thrown around, referencing the fact that it’s rumored that the San Andreas fault could unleash a state crushing earthquake at any moment without warning; but is this really the case? As Eagle Rock is quite far from the fault itself, is our community even at risk?
Earthquakes aren’t sudden natural disasters that happen for no reason. Earthquakes are the result of decades of stress on a fault between tectonic plates building up and releasing all at once. The San Andreas fault is composed of two massive tectonic plates that hold North America and the Pacific Ocean, and each one slips past the other one at a rate of around 1.5 inches a year-or about the same speed that your fingernails grow at. However, when the land that sits on the edges of the faults get locked into place by friction, the stress from each plate attempting to move slowly builds up. The last earthquake on the San Andreas fault was in 1857, and with an average time between earthquakes of 100 years, we’re very clearly overdue.
As for how soon an earthquake could hit us, let alone the Big One itself, researchers have been monitoring the San Andreas fault for over a decade now to get a better understanding of the built up stress. According to Thomas Jordan, director of the South California Earthquake center, “The springs on the San Andreas system have been wound very, very tight. And the southern San Andreas fault, in particular, looks like it’s locked, loaded and ready to go.” After all, if the fault hasn’t triggered an earthquake for all this time, what’s the likelihood that it might anytime in the near future?
According to the US Government Earthquake Hazards Program, there’s a 20% chance within the next 20 years that it could happen at any moment near Los Angeles. However, if the slip starts further up north near San Francisco, the probability of it happening in the next 20 years spikes up to nearly 75%. The overall probability of an earthquake greater than a magnitude of 6.7 striking within the next 30 years is over 99%, just shy of being 100% certain. Quite clearly, we’re at constant risk for an earthquake happening, whether we like it or not.
Just because the earthquake could happen at any time doesn’t mean we’re necessarily at risk here in Eagle Rock, right? While it may be the case that Eagle Rock is over 100 miles away from the San Andreas fault itself, the main fault isn’t the only possible trigger in the entire San Andreas fault zone. Many smaller branches of the fault break off all across California, making their way through spots all over LA. For example, a fault line runs directly under Dodger Stadium, threatening the entire surrounding area with a powerful earthquake. Leading seismologist Lucy Jones stated in an interview in 2012 that, “The earthquake is inevitable and disruption is inevitable.” Still, even more worrying is that a separate fault branch runs directly under Pasadena- and right into Eagle Rock. Without a doubt, we’re definitely at risk of a destructive earthquake.
Earlier this year, Eagle Rock High School became the first public school in California to receive a new early warning system for earthquakes that are to be installed across the city. The system was developed by Early Warning Labs, who’ve partnered with LAUSD to install the system into the already existing public announcement systems of three public schools. Through a hard-wired network of sensors that detect the initial wave of seismic activity, the early warning system can alert students and staff before the shaking even begins. The warning also includes the level of expected shaking, and how much time is left to get to cover. A similar system is being used to develop Early Warning Labs’ phone app QuakeAlert, which uses an online version of the same system across L.A. to warn you of an earthquake before it strikes. The app is free to download, and is highly recommended to anyone living in the L.A. area.
So what should you be doing about it? The easiest step you can take is to talk with your family about an Earthquake plan. Wherever you might be in your home, remember Drop, Cover, Hold. Drop close to the ground, Cover under anything you can, Hold onto a stable object with one hand to keep yourself as stationary as possible. It also is a great idea to keep gallons of bottled water and non-perishable foodstuffs stored somewhere safe and easily accessible. There are plenty of government resources on the internet to help prepare yourself better for an earthquake, and as someone living in a high risk area, it’s important to know how to stay safe in an earthquake.