Week-long ‘megaquake’ preparedness campaign brought to an end in Japan

Government officials in Japan have ended a week-long information campaign urging caution and preparedness for a possible “megaquake” — an earthquake of magnitude eight or higher — striking the Pacific coast.

The announcement on Thursday came after no abnormal seismic activity was detected during the past week.

The Japan Meteorological Agency issued the country’s first-ever “megaquake advisory” on August 8, hours after a magnitude 7.1 earthquake struck off south-western Japan.

That quake happened on the western-most edge of a disaster-prone undersea trench called the Nankai Trough and the meteorological agency said the risk of another big one hitting somewhere along the trough was higher than normal.

The Government, in response, designated the past week as a period of “special caution” and preparedness in the region along the trough, calling on residents to be prepared to flee immediately.

Cabinet Office disaster response official Tsukasa Morikubo announced the end of the caution period as of Thursday evening, noting that seismologists detected no abnormal seismic activity around the Nankai Trough in the past week.

The end of the special caution period does not mean there is no risk of a megaquake, said Mr Morikubo, urging people to keep up their usual earthquake preparedness.

“A next major one can hit anytime, anywhere,” he added.

The Government last week called on more than 700 municipalities in 29 of the 47 Japanese prefectures to review their preparedness and evacuation plans in response to the August 8 advisory.

The advisory led to widespread confusion and fear even in a country where people are used to moderate temblors and affected travel plans during Japan’s mid-August holiday week.

Many rushed to stock up on emergency food and goods even in the capital region outside of the at-risk area.

Some coastal towns closed their beaches or cancelled annual fireworks, and train operators serving the area have reduced speed.

Disaster management officials at the Cabinet Office said the decision on whether to continue voluntary measures taken during the week is up to municipalities, transportation services and other businesses.

There is a 70% to 80% chance of a magnitude eight or nine quake associated with the Nankai Trough within the next 30 years, seismologists say, but its location or a timeframe are unknown.

The Nankai Trough, an undersea trench spanning about 500 miles along most of the southern half of Japan’s Pacific coast, has repeatedly caused devastating quakes and tsunamis.