Upgrading the Seismic Station on Farallon Islands
UC Berkeley Seismology Lab engineers recently upgraded the remote and critical Farallon Islands seismic station, which monitors the San Andreas fault. The sensors on the rocky outpost west of San Andreas fault provide critical data on state's most dangerous fault. Watch this video to learn more.
“This was one of the first instruments put here when Berkeley started to build the Berkeley Digital Seismic Network in the 1990s,” said seismology lab director Richard Allen as he accompanied his crew on a survey of the outdated station. “It’s been upgraded a couple of times since, but this is our opportunity to really turn this into a state-of-the-art site where we have much lower noise levels and we can really detect all earthquakes that are occurring in the region.”
Transcript
00:00:00 (elephant seal barking) Every year thousands of animals visit the Farallon Islands about 30 miles off the coast of San Francisco. But only a few scientists visit this protected wildlife sanctuary. (Helicopter sounds) Most are biologists but these researchers aren't here for the birds or the marine mammals. So, I'm Richard Allen. I'm the director of the UC Berkeley Seismology Lab. Allen is here with a team of engineers to see this.
00:00:28 Okay, so this this pile of rocks is the seismic station. It's one of nearly 200 such stations across the state of California that can detect earthquakes. It's also a critical part of the earthquake early warning system which sends alerts to the MyShake app. Developed by Allen and his team, it could help save lives and billions of dollars in damages. this instrument detects an earthquake, if it's one of the four instruments closest to the epicenter of the earthquake, it's used to locate the earthquake, estimate the magnitude of the earthquake, and then we send a warning out to people that people can get on their phone using the MyShake app.
00:01:03 if you feel shaking or if you get a warning about shaking you just drop, cover and hold on. In the Loma Prieta earthquake and in the Northridge earthquake more than half of the injuries were because people either fell over or things fell on people. So if everybody drops, takes cover and holds on to something then we could halve the number of injuries in future earthquakes. So that's the first reason is hazard reduction but the other reason is research. We need to understand earthquake processes. But to understand the earthquakes better this station needs to be upgraded and that means a lot of new equipment.
00:01:38 And the only way to bring that all out efficiently is actually to fly it in on a helicopter. Thousands of pounds of gear are being delivered. Inside one crate is a brand new seismometer. So what type of, what type of sensor is this? This is a Streckeisen STS-5A. Uh, it will go... The Farallon Islands provide seismologists like Allen with crucial data about one of California's most famous and most dangerous faults So the San Andreas fault basically runs right down the western edge of California. We're all ready for a magnitude 7, a magnitude 8.
00:02:14 We want to put out seismic instruments around the fault and what's really important is having them on both sides of the fault. And so that's why a site like this on the west side of the fault and it allows us to look east onto the fault and it's fairly unique. We don't have many sites, unfortunately, on this side of the fault. This is such a critical site. It was one of the first instruments that was put here when we started to build, when Berkeley started to build, the Berkeley digital seismic Network. There is the mouse! I saw it! Thanks to funding from the California Governor's Office of Emergency Services new racks of electronics will replace a system
00:02:46 that has become home to invasive mice. Weather-proof and in this case, mouse-proof. This is our opportunity to really turn this into a state of art site where we have much lower noise levels and we can really detect all earthquakes that are occurring in in the region. During a week that saw storms with 70 mile per hour winds and two-story waves the team set up the new sensors ran cabling to the new rack and hooked it all up to the antenna. Once the Farallon station is calibrated and brought online
00:03:17 it will join a comprehensive sensor network across California. We've actually been rapidly expanding in order to support the early warning system and we only have four stations left to build. Stations like the one on the Farallon Islands might give people a few seconds to prepare for the shock waves of an earthquake but they can't predict them. Yeah, so we're not predicting earthquakes. We do not know how to predict earthquakes. What we do is we predict the shaking. What I mean by that is that, when the earthquake, if we have a fault plane like this earthquakes typically occur at 8 kilometers depth in California So that an earthquake nucleates on the fault
00:03:52 the energy radiates out and it's detected by instruments close by. And it's once these instruments have detected the earthquake we can then predict the shaking that will occur further away from the site. So we detect it with the closest seismic stations and then we predict the shaking that's coming further away. And that means you typically get a few seconds, maybe a few tens of seconds, of warning. Installing and maintaining this system isn't cheap it costs $45 million a year but that's money well spent, says Allen.
00:04:22 I think it's a hugely valuable system. In the Northridge Earthquake it's estimated that there was two to three billion dollars of losses just due to the injuries. So if we can halve that number then the entire system has paid for itself in just one earthquake. so I think it's really valuable I think it's also valuable beyond just the early warning in the sense that people are very interested in early warning it makes people think about earthquakes so we're more likely to have a preparedness kit. We're more likely to think about our homes and our offices and how safe they are to live and work in. And so I think it actually goes a long way to reducing the overall impact of earthquakes not just because of the warnings but because more people are thinking about the earthquake problem and looking to reduce the hazard.
00:05:00 (birds chirping, seals barking)