Earthquakes are some of the most powerful naturally occurring events on the planets. Maybe you have even experienced one at some point in your life. For the uninitiated, earthquakes involve the powerful movement of rocks in the Earth’s crust.
The rapid release of energy creates seismic waves that travel through the earth. To measure the strength of an earthquake, researchers use seismometers.
Yet, what is interesting is that you are unlikely to feel a magnitude 3 earthquake but a magnitude 6 earthquake could potentially cause large damage. Megaquakes can be wildly destructive, as seen in the magnitude 9.0 earthquake that killed over 15000 people on March 11, 2011, in the Tohoku region of Japan.
After going through databases that date back to the early 1990s, researchers from the University of Oregon have come across information that could be useful in creating systems for the early detection of potentially destructive earthquakes.
The research team discovered a 10-15 second moment during an event that could signal a magnitude 7 or larger megaquake. Using GPS information Diego Melgar, a professor in the Department of Earth Sciences at the University of Oregon, believes that this data could drastically improve the value of earthquake early warning systems.
The team discovered that there is a point in time when an early stage earthquake transitions into a slip-pulse where mechanical properties point to the magnitude. GPS data that picked up the peak rate of acceleration of ground displacement reveal that GPS picks up the smallest movements of the first moments of an earthquake.
Basically, the rate of acceleration of ground displacement tracked with GPS in real-time could be key.
Melgar came across these slip plus patterns examining the extensive databases that contain information on more than 3,000 earthquakes. Within the research, Meglar found indicators of displacement acceleration that surface between 10-20 seconds into events and that were seen for 12 major earthquakes occurring in 2003-2016.
"We can do a lot with GPS stations on land along the coasts of Oregon and Washington, but it comes with a delay," Melgar said. "As an earthquake starts to move, it would take some time for information about the motion of the fault to reach coastal stations," says Melgar.
"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."