Six injured after strong quake off northern Japan triggers small tsunami waves

TOKYO: At least six people were reported injured on Tuesday, a day after a powerful earthquake struck in Pacific waters off northern Japan, while authorities said there were no signs of major damage from the tremor that also set off tsunami waves of up to 80 centimetres.

The Japan Meteorological Agency said the magnitude 7.7 earthquake occurred off northern Iwate prefecture on Monday. The shaking was strong enough to sway large buildings in Tokyo, which is located hundreds of kilometres from the epicentre.

According to a statement from the Fire and Disaster Management Agency, six people had been reported injured by 8am (2300 GMT Monday), including two who were seriously hurt. The agency also said there had been no reports of fires or damage to key facilities.

Japanese authorities had initially issued a warning for tsunami waves of up to three metres, but that alert was later lifted. An 80-centimetre wave was recorded at a port in Kuji in Iwate, while a series of smaller waves were also observed in other parts of northern Japan.

Agency warns of heightened megaquake risk

Hours after the earthquake, the Japan Meteorological Agency warned that the possibility of another very large earthquake had increased. The agency said that the likelihood of a new, huge earthquake occurring is relatively higher than during normal times.

The warning referred to the risk of a megaquake, defined in the report as a tremor with a magnitude of 8.0 or stronger.

Meanwhile, municipalities in the affected area issued non-compulsory evacuation directives for more than 182,000 residents, according to the Fire and Disaster Management Agency.

Japan’s long exposure to seismic activity

Japan is among the most earthquake-prone countries in the world. It lies across four major tectonic plates on the western edge of the Pacific Ring of Fire.

The country, which has a population of around 125 million, experiences roughly 1,500 earthquakes each year and accounts for about 18 percent of earthquakes recorded globally. Most of these tremors are minor, although their impact depends on where they occur and how deep below the Earth’s surface they originate.

Japan continues to live with the legacy of the 2011 undersea earthquake, which measured magnitude 9.0 and triggered a tsunami. That disaster left around 18,500 people dead or missing and caused a severe nuclear accident at the Fukushima plant.

Authorities were continuing to monitor the situation following Monday’s quake, which caused injuries and prompted evacuations but, according to official statements, did not result in serious structural damage or major disruption to critical facilities.