7.5-magnitude quake hits northern Japan; tsunami alert, evacuation advisories issued

A strong earthquake measuring about 7.4 on the Richter scale struck northern Japan on Monday (April 20), and the Japan Meteorological Agency issued a tsunami alert in the region, sending residents rushing to safer grounds. So far, no major injuries or damages have been reported.

The Cabinet Office and the Japan Meteorological Agency said there is 1 per cent chance of a mega-quake occurring on the northern Japanese coast in the next week or so, following the powerful quake earlier Monday near the Chishima trough. Officials said the advisory is not a quake prediction but urged residents to raise their preparedness, such as emergency food and their grab bag, just in case, while continuing their daily lives.

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The advisory for the region is the second in recent months. One was issued following another major quake in December that left dozens injured. No major subsequent quake occurred.

Monday’s quake, registering a preliminary magnitude of 7.5, occurred off the coast of Sanriku in northern Japan at around 4:53 pm (0753 GMT), at a depth of about 10 kms, the agency said. A tsunami of about 80 cms (2.6 feet) was detected at the Kuji port in the Iwate prefecture within one hour of the quake, and a smaller tsunami of 40 cms (1.3 feet) was recorded at another port in the prefecture, the agency said.

Tsunami alert still in place

The tsunami alert and advisory were still in place in Japan, with warnings of a wave of up to 3 metres (10 feet), but the US-based Pacific Tsunami Warning Centre said the tsunami threat from the quake “has now passed”. The Japanese agency urged residents in the region to immediately stay away from the coast or along rivers and take shelter on higher ground. It also cautioned people in the area against possible aftershocks for about a week.

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Footage on NHK television showed many people driving up to parks and other facilities on higher ground. In the town of Tomakomai in Hokkaido, a resident came to a hilltop park after picking up his child at a cram school and said he planned to stay until the alert is lifted.

Evacuation advisories

Iwate and three other northern prefectures issued non-binding evacuation advisories to more than 128,000 residents, according to the disaster management agency.

The Fire and Disaster Management Agency said officials are assessing the situation, but so far, no damage or injuries have been reported, including at power stations and other facilities. The Nuclear Regulation Authority said nuclear power plants and related facilities in the region were all intact, and no abnormalities were detected.

Transport halted, epicentre offshore

Rail services on the Tohoku Shinkansen line were suspended between Tokyo and Shin-Aomori as a precaution following the quake. Early reports, including those carried by Sky News, placed the magnitude at 7.3, with the epicentre located off the Sanriku coast at a depth of roughly 10 kms beneath the seabed.

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Later in the day, NHK reported that a tsunami had already been observed off parts of Japan’s coastline. As assessments continued, Japan’s meteorological agency revised the quake’s magnitude upward to 7.5, underscoring the scale of the event and the need for continued vigilance.

9.0 magnitude quake in 2011

It's been 15 years since a magnitude 9.0 earthquake and tsunami on March 11, 2011, ravaged parts of northern Japan, caused more than 22,000 deaths, and forced nearly half a million people to flee their homes, most of them due to tsunami damage.

Some 160,000 people fled their homes in Fukushima because of the radiation spewed from the tsunami-hit Fukushima Daiichi nuclear power plant. About 26,000 of them haven't returned because they resettled elsewhere, their hometowns remain off-limits, or they have lingering concerns about radiation.

(With agency inputs)