News, aftershocks, tsunami warnings and more

A seismologist with the U.S. Geological Survey has warned that aftershocks from the magnitude 7.5 earthquake that struck western Japan on Monday could last for months.

Susan Huff said people living in that part of the country have felt earthquakes before, but she believes this is “the biggest earthquake we’ve ever seen” – meaning most residents probably don’t expect an earthquake of this scale. There is no experience of seismic event.

Hoff says, “An earthquake of this magnitude will still cause aftershocks. It could easily lead to aftershocks even larger than magnitude 6, which would be a danger in itself.”
The initial earthquake collapsed buildings, sparked fires and triggered tsunami warnings as far away as eastern Russia, prompting evacuation orders for residents of affected coastal areas of Japan.

In 2011, a magnitude 9.1 earthquake off eastern Japan caused a tsunami with 30-foot-high waves, damaging several nuclear reactors. Huff said that, by comparison, although the risk of a tsunami of that size in the case of Monday’s earthquake is likely lower than in 2011, people living near the coast should still evacuate.

Some of the first reports came from the city of Wajima in Ishikawa Prefecture, where tsunami waves of about 1.2 meters (3.9 ft) were seen around 4:21 p.m. local time, according to Japanese public broadcaster NHK.

After all, location plays a big role in the magnitude of an earthquake’s impact, Huff said.

Huff said the earthquake was shallow. “The location where the fault was moving was very close to where people lived, and that could concentrate shaking near where the earthquake occurred. The energy had to be transferred and dissipated before it could reach where people live.” Don’t get much time for people,” he explained.