Experts in Japan are sounding an alarm about a potentially catastrophic earthquake off the coast of Hokkaido. A team of researchers from Tohoku and Hokkaido Universities, along with the Japan Agency for Marine-Earth Science and Technology, has warned that stress energy building up in an undersea trench could trigger a massive earthquake, possibly reaching magnitude 9.

The research team spent five years studying the Chishima Trench, an area where an ocean plate dives beneath a continental plate. They installed GPS stations on the seabed to monitor plate movements. Their findings show that the plates are firmly connected and strain is accumulating. If this strain has been building up since a massive earthquake struck the region in the 17th century, it could result in the energy released by a mega-quake.

According to government experts, the likelihood of a quake of magnitude 8.8 or greater occurring in the region within the next 30 years ranges from 7 to 40 percent.