Japan Braces for Possible Aftershocks Following Major Earthquake

Officials in Japan have warned of an increased risk of a huge earthquake in the next week after a 7.7 magnitude quake struck off the north-east coast, triggering an evacuation order and warnings of 3m (10ft) tsunami waves.

Thousands of people were told to leave coastal areas for higher ground following the quake in waters off Iwate prefecture, 530km (330 miles) north of the capital Tokyo. The biggest tsunami waves measured 80cm. Tsunami warnings and advisories were lifted hours after the quake on Monday.

However, Japan's meteorological agency has indicated that quakes causing even stronger shaking could occur in the next week, potentially generating bigger waves.

Authorities expressed that the risk of a quake measuring 8.0 magnitude or higher was relatively higher than during normal times. The populace remains wary, recalling memories of the catastrophic quake in 2011, which resulted in a tsunami, killing over 18,000 people and a nuclear meltdown at Fukushima.

After Monday's undersea quake, recorded at a depth of 10km, warnings of possible bigger waves were issued to residents closest to the epicenter in Japan's main island, Honshu, and the northern region of Hokkaido. Tremors were felt as far away as Tokyo.

Tsunami alerts remained in place in Hokkaido hours after the seismic event struck at 16:52 local time (08:52 BST). Eyewitness accounts described a rapid response to evacuation alerts, though this quake was generally perceived as milder.

Japan's Cabinet Secretary Minoru Kihara noted some bullet trains were disrupted, and approximately 100 homes were without power, though no significant damage or injury reports were made. Services resumed by Monday night.

The tsunami alert was eventually downgraded and lifted just before midnight local time.

Japan's geographical location along the Ring of Fire contributes to its experience of around 1,500 earthquakes each year, comprising about 10% of global earthquakes of magnitude 6.0 or higher. The 2011 disaster remains a painful reminder of the dangers posed by seismic activity.