Japan issues megaquake warning as government says '98-foot tsunami' could wreak havoc.

Japan has issued a megaquake advisory after Monday's 7.6-magnitude earthquake struck off the nation's eastern coast

Japan's Prime Minister Sanae Takaichi speaks to reporters at the prime minister's office in Tokyo after a strong earthquake struck northeastern Japan.

Japan has issued a megaquake warning following Monday's earthquake that hit off the country's eastern coast.

Following Monday's quake, which registered at 7.6 on the Richter scale and is considered a major earthquake capable of causing extensive damage across hundreds of kilometres, the Japan Meteorological Agency has warned of an increased risk of a subsequent, magnitude-8 or larger quake within the next week, reports The Mirror.

Reports suggest another offshore megaquake in the Hokkaido-Sanriku area of Japan could trigger a tsunami up to 98 feet high in the region, potentially killing up to 199,000 people, destroying as many as 220,000 homes and buildings, and causing estimated economic damages of up to 31 trillion yen ($198 billion).

According to government estimates, as many as 42,000 people could suffer from hypothermia during the winter.

Consequently, the JMA has issued an earthquake alert warning of an increased risk of a significant tremor of magnitude 8 or higher along the Japan Trench and the Chishima Trench off Hokkaido.

Government officials are now urging residents, particularly those residing along coastal regions, to be ready to evacuate at the first sign of tremors. The warning spans from Hokkaido to Chiba Prefecture, marking the first advisory of its kind for the region since the introduction of the mega-quake warning category in 2022, and covers approximately 800 miles of coastline.

Japanese Prime Minister Sanae Takaichi has issued a stern warning to her citizens to stay alert, regardless of their location, and to evacuate promptly if any tremors are detected.

"Due to this earthquake, the likelihood of a large earthquake occurring from Hokkaido to the Sanriku offshore region is now assessed to be higher than normal. Accordingly, the 'Off the Coast of Hokkaido and Sanriku Subsequent Earthquake Advisory' has been issued," she announced on Tuesday.

In her address to the nation, she emphasised that while it remains uncertain whether a significant earthquake will indeed occur, locals should still prepare accordingly.

A 7.2-magnitude earthquake hit off northern Japan earlier this week

A 7.2-magnitude earthquake hit off northern Japan earlier this week (Image: @@BNONews)

"Regardless of whether your area was affected by this earthquake, residents in regions where disaster-preparedness measures are advised should, over the next week or so, pay close attention to information from the Japan Meteorological Agency and local authorities," she advised.

"In addition to routinely confirming earthquake preparedness - such as identifying safe evacuation sites and routes and securing furniture - please stay prepared to evacuate immediately if you feel any shaking."

Officials stressed that the advisory does not constitute a forecast, noting that the likelihood of a magnitude eight or greater earthquake remains at just one per cent. Nevertheless, Japanese authorities hope the warning will act as a reminder for those who may have grown complacent following Japan's devastating 2011 earthquakes that claimed nearly 20,000 lives and obliterated a nuclear facility.