Why Japan remains on high alert for a ‘megaquake’ after tsunami warnings

Japan has reportedly issued a warning of an increased risk of a major earthquake expected in the coming week. This follows a 7.7 magnitude quake struck off the north-east coast. Which prompted evacuation orders and warnings of 3-meter (10ft) tsunami waves.

Given the severity of the situation, thousands of people were told to leave coastal areas for higher grounds after the quake struck in waters off Iwate prefecture which is approximately 530 km (330 miles) north of Tokyo. 

The largest tsunami wave was measured at 80cm. Tsunami warnings and advisories remained in place for several hours following Monday’s earthquake.

In this connection, Japan’s meteorological agency issued warnings that quakes “causing even stronger shaking could occur in the next week, producing bigger waves”.

Following a significant undersea earthquake off Japan coast, authorities warned that the risk of a megaquake measuring 8.0 or higher is currently elevated. 

Over 170,000 people across several prefectures were ordered to move to higher ground or evacuation buildings.

Initial warnings reached the second-highest alert level before being downgraded and eventually lifted at mid-night.

Bullet train services were disrupted, and approximately 100 homes lost power, though no major damage or injuries were immediately reported. 

The quake struck at a depth of 10km, primarily affecting the main island of Honshu and the northern region of Hokkaido. Residents reported mild shaking but remained on high alert due to loudspeaker warnings from local authorities.

Public anxiety remains high due to memories of the 9.0-magnitude quake in 2011, which caused a devastating tsunami, killed 18,000 people, and led to the Fukushima nuclear meltdown. 

Located on the “Ring of Fire”, Japan accounts for 10% of the world’s earthquakes magnitude 6.0 or higher, experiencing roughly 1, 500 tremors annually. 

Additionally, the meltdown at Fukushima marks one of the most catastrophic nuclear incidents in history. The government has issued stark warnings for people to stay safe and move to higher ground.