Japan issues first ‘megaquake’ warning for Nankai Trough after strong earthquake hits Miyazaki

The powerful 7.1 earthquake was felt throughout southern Japan yesterday. Photo / Japan Meteorological Agency

An earthquake with an intensity of lower 6 on the Japanese seismic scale of 7 hit southern Miyazaki Prefecture at about 4.43pm on Thursday, according to the Japan Meteorological Agency.

The JMA later announced “Mega-thrust Earthquake Attention”, indicating the necessity for caution regarding a megaquake in the Nankai Trough area. This is the first time the JMA has issued so-called Nankai Trough Earthquake Extra Information.

The agency advised residents to continue their daily lives while ensuring they were prepared for disasters.

Nankai Trough Earthquake Extra Information may be issued when an earthquake occurs in part of the Nankai Trough area, as part of efforts to assess the probability of a subsequent megaquake in the Nankai Trough area.

The magnitude-7.1 temblor had a hypocentre about 30km deep in the Hyuga-nada Sea. A seismic intensity of lower 6 was recorded on the plains of southern Miyazaki Prefecture, while an upper 5 was felt in Miyazaki’s mountainous region and in the Osumi area of Kagoshima Prefecture.

The plains in northern Miyazaki Prefecture and the Satsuma area of Kagoshima Prefecture both experienced a seismic intensity of lower 5.

The earthquake caused a tsunami with a height of 50cm to reach Miyazaki Port in Miyazaki at 5.14pm, according to the JMA.

A 40cm-high tsunami was recorded in the prefecture’s Nichinan at 5.23pm. In addition, 30cm-high tsunamis were recorded in Tosashimizu, Kochi Prefecture, at around 5.46pm. Tsunamis of 10cm in height reached Miyazaki’s Hyuga at 5.13pm.

The JMA warned people not to approach the coasts, in order to avoid tsunamis.

“Tsunami have been observed and coastal areas are dangerous,” a JMA official said at a press conference on Thursday.

A 7.1-magnitude earthquake struck off the coast of Miyazaki prefecture on the southern Japanese island of Kyushu on Thursday, the Japan Meteorological Agency said, issuing a tsunami warning for Kyushu and the neighboring island of Shikoku. https://t.co/Ql8D7Mpe6M

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Emergency response office set up

The Government set up an emergency response office on Thursday. The office is operating under the crisis control centre of the Prime Minister’s Office.

Prime Minister Fumio Kishida on Thursday ordered that measures be taken to respond to the strong earthquake.

Such measures include providing the public with accurate information on tsunami and evacuation in a timely manner, and making thorough efforts to prevent damage.

The extent of the damage was to be immediately assessed, and relevant parties were to work closely with local governments and do all they could to implement emergency disaster response measures while prioritising the protection of human lives.

Kyushu Electric Power Co said its Sendai nuclear power plant in Kagoshima Prefecture and Genkai nuclear power plant in Saga Prefecture were operating normally.

Shikoku Electric Power Co also said its Ikata nuclear power plant in Ehime Prefecture was operating normally.

The Kyushu and Nishi Kyushu Shinkansen lines resumed services around 5.20pm, after making emergency stops following the earthquake, according to Kyushu Railway Co.