There is a giant earthquake building beneath Bangladesh, according to an international team of researchers. Although they do not know when the disaster will occur, the team believes that 140 million people in this region could be affected once it strikes.

The researchers estimate that the giant earthquake might reach a magnitude of 9 once the stress is released. As explained by the study published on July in the journal Nature Geoscience, the threat is a subduction zone, where Earth’s crust or tectonic plates get pushed under one another.

Earthquakes usually happen in these zones, such as the 2004 Indian Ocean quake and tsunami that killed 230,000 people and the 2011 Tohoku quake and tsunami off Japan that killed more than 15,000 and caused the Fukushima nuclear disaster. However, these subduction zones were previously believed to only occur under the ocean. The new threat is under the land, making it even worse.

Giant earthquake

Potential quake zone.

Since 2003, the researchers placed GPS instruments to observe any ground movements. They found that eastern Bangladesh and a tiny part of eastern India are pushing diagonally into west of Myanmar at a rate of 46 millimeters or 1.8 inches each year.

Once the stress is released, buildings, roads and people would get sucked in as the substrate shakes and liquefies. The river banks in the region could drown everything, like what happened centuries earlier.

Unfortunately, Bangladesh is not equipped for such problem. The team says that the overpopulated country has poor infrastructure and its power plants and natural gas fields are close to earthquake-prone areas.

Further studies are still ongoing. Other researchers hope that 70 seismometers will be deployed in other places where the potential earthquake would extend, particularly in Myanmar, to gather more information about the threat.

“We don’t have a good idea of its geometry, we don’t know how far it goes down,” says James Ni, a seismologist at New Mexico State University. “We need more data.”