ShakeAlert Gets Satellite Boost for Earthquakes

ShakeAlert, the earthquake early warning system for California, Oregon, and Washington, just took a big step forward by adding real-time satellite data to its arsenal. This upgrade, managed by the U.S. Geological Survey (USGS), is all about getting more accurate earthquake magnitude readings, which can really help when it comes to emergency responses.

As ShakeAlert operations team lead says, “This can tell us how big an earthquake is sooner, which ultimately translates to getting alerts out to people faster.” This is crucial in making sure that everyone is prepared as quickly as possible.

Previously, ShakeAlert relied only on data from seismometers. These instruments measure seismic waves created by earthquakes, and scientists have developed special algorithms to estimate an earthquake’s size from the data collected. But those instruments had limitations—especially during major quakes.

When a strong earthquake hits, ShakeAlert automatically sends alerts to various partners, including Google and NASA‘s Jet Propulsion Laboratory. This means quicker public announcements and quicker notifications on cell phones so that people can be ready before the shaking starts.

The system was primarily using broadband seismometers, which could struggle to measure large earthquakes, especially when seismic waves are too powerful. Think of it like a punk rock singer screaming into a microphone — at some point, it just becomes noise. This means that they could only get accurate readings up to a magnitude of about 7.0.

Stronger devices, called strong-motion seismometers, can record the huge waves from big earthquakes. But there’s still a problem when it comes to determining magnitudes right above the epicenter, as shaking can become indistinguishable during strong quakes.

According to a USGS geophysicist, “There’s not actually much difference between shaking for a magnitude 8 and magnitude 9 earthquake.” Understanding what happens during these intense moments can greatly affect warning times, which is critical during emergencies.

That’s where Global Navigation Satellite Systems (GNSS) come in handy. Unlike seismometers, they measure ground displacement, without worrying about shaking. As a result, they provide more accurate magnitude measurements, especially during the largest earthquakes.

The ShakeAlert system is currently using only the U.S. satellite network (GPS) but might expand to incorporate satellite data from other countries in the future. You can see how better magnitude measurements are vital when it comes to emergency actions and timely warnings.

One geodesist highlighted that, “If you underestimate the earthquake, you underestimate the area that’s affected.” This means that a wrong or slow estimate could leave people unprepared when they needed to act quickly.

Take for instance the devastating Great Tōhoku Earthquake in Japan in 2011. While they had a warning system in place, the magnitude wasn’t accurately determined until 20 minutes after the initial shaking, which can make all the difference when every second counts.

Scientists have been eager to merge GNSS sensors with existing early warning systems for over a decade. One researcher noted that bringing these two systems together could offset weaknesses and enhance overall capabilities.

So, after all this time and effort, getting this integration right really matters. The ShakeAlert team is thrilled that they can finally use both GNSS and seismometer data together, contributing to a safer future.