New study shows GPS data can predict large earthquakes earlier

Scientists discover how to predict megaquakes earlier to improve warning systems.

New study shows GPS data can predict large earthquakes earlier

Firefighters putting out an earthquake-caused fire on July 6, 2019 in Ridgecrest, California.

Photo by Mario Tama/Getty Images
  • Earthquakes of 7+ magnitude share a particular pattern, find seismologists.
  • The pored over data of over 3,000 earthquakes to spot a "slip pulse".
  • The scientists advocate using real-time GPS sensor data in early warning systems.


As the 2019 California earthquakes remind us, these natural events can be quite nerve-racking and dangerous. Potential for terrible destruction is always just a tremor away. That's probably the worst thing about earthquakes – they come out of nowhere and cause the most mayhem simply because of their sheer suddenness. Predicting earthquakes would save lives and property, and a recent study hopes to accomplish just that.

Seismologists Diego Melgar and his colleague Gavin P. Hayes were at first looking for databases to simulate the magnitude 9+ Cascadia megaquake of 1700. But they ended up discovering a very peculiar pattern. They employed data collections of earthquakes going back to the early 1990s and their background in geophysics to spot a specific moment, happening 10-15 seconds into an earthquake event. That moment, derived from GPS data, can indicate a quake of magnitude 7 or larger.

The scientists used GPS information, in particular, because it caught even the smallest initial movements along a fault, showing the strongest acceleration of ground movement. The seismologists identified a pattern in the data called "a slip pulse" that happened during the transition period, when displacement between two plates was taking place. The top rate of that displacement predicted if the quake would be small or go mega, found the researchers.

How did they know they were on the right track? The scientists performed physics-heavy analysis of numerous databases of 3,000+ earthquakes to confirm their methodology. They correctly picked out all 12 quakes of 7+ magnitude from the early 1990s till now in two U.S. Geological Survey databases. They also hit upon the same pattern in European and Chinese databases, reports a University of Oregon press release.

"It was super exciting," shared Melgar. "As Gavin and I pored through the data for what were really unrelated reasons, we began to see these trends. We had a bit of a eureka moment where we, well, if what we're seeing is true, it means something about how earthquakes start."

Vehicles driving over a crack on Highway 178, near Trona. This follows a 6.4-magnitude earthquake in Ridgecrest, California on July 4, 2019.

Credit: Frederic J. Brown/Getty Images

The scientists think their research can lead to a greater amount of GPS stations to improve early warning system, especially ShakeAlert, along the West Coast. The sensors can be placed on the seafloor to counter the delay in relaying valuable quake information.

"We can do a lot with GPS stations on land along the coasts of Oregon and Washington, but it comes with a delay," Melgar explained. "As an earthquake starts, it would take some time for information about the motion of the fault to reach coastal stations. That delay would impact when a warning could be issued. People on the coast would get no warning because they are in a blind zone."

Melgar's previous work on real-time GPS data found it could give an extra 20 minutes of warning in cases of tsunamis.

Diego Melgar is a researcher at the University of Oregon, while Gavin P. Hayes is a seismologist with the USGS National Earthquake Information Center in Colorado.

Read their study in Science Advances.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

BepiColombo

Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

Photo by Martin Adams on Unsplash
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Credit: Helen_f via AdobeStock
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