Earthquakes can create powerful seismic waves capable of destroying entire cities, making early detection and prediction crucial. Yet despite seismologists’ considerable efforts, reliable earthquake predictions have continued to elude them. But geologists have now found possible early signatures of massive earthquakes – dubbed megaquakes – following groundbreaking new GPS research. A landmark study has reveals the tell-tale seismic pattern occurs between 10 and 15 seconds into an earthquake event.
Scientists discovered the warning sign after analysing GPS records of peak ground displacement during multiple earthquakes.
An aggregate of GPS databases shows a point in time when the beginnings of an earthquake takes the form of a “slip pulse”, the mechanical functions of which scale with magnitude.
The discovery allowed geologists to differentiate between small to medium-sized earthquakes and large to extra-large megaquakes.
Professor Diego Melgar, of the University of Oregon, said: “To me, the surprise was that the pattern was so consistent.
“These databases are made different ways, so it was really nice to see similar patterns across them.”
Researchers identified the displacement acceleration signature between 10 seconds to 20 seconds into the beginnings of 12 major earthquakes that took place between 2003 and 2016.
Although GPS instruments are rarely used for earthquake warning systems, they are already located along most quake-prone areas around the world.
GPS instruments are positioned along several fault lines connected to the massive Cascadia subduction zone located off the coast of the Pacific Northwest.
Professor Melgar added: ”We can do a lot with GPS stations on land along the coasts of Oregon and Washington, but it comes with a delay.
“As an earthquake starts to move, 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.”
Professor Melgar and peers in Japan are currently considering innovative ways to monitor fault movements on the seafloor.
An earlier study by Melgar determined such data could add an additional 20 minutes of warning time for a possible tsunami.