Strong Earthquake Hit Southern Japan on Monday Night; Authorities Decide No Increased Risk of Nankai Trough Quake

The Yomiuri Shimbun
Water floods a city road in Miyazaki on Monday.

An earthquake with an intensity of lower 5 on the Japanese seismic scale of 7 struck Miyazaki Prefecture at about 9:19 p.m. on Monday.

The Japan Meteorological Agency issued a Nankai Trough Earthquake Extra Information advisory with the keyword Under Analysis on the day, indicating that it was examining the likelihood of Nankai Trough Earthquake increasing. At 11:45 p.m., the JMA announced that it had concluded its research and decided that the possibility of such a quake had not increased.

Miyazaki, Shintomi and Takanabe in the prefecture saw an intensity of lower 5, with a magnitude of 6.6 and an epicenter about 36 kilometers deep in the Hyuga-nada Sea.

The JMA held a special meeting of an evaluation and review panel at 10:30 p.m., after the announcement of the advisory. It concluded the scale of the earthquake was below a moment magnitude scale of 7.0, meaning it did not meet the criteria to issue an advisory with the phrase Megathrust Earthquake Attention.

A magnitude-7.1 earthquake occurred near the epicenter of Monday’s earthquake in August. The JMA issued its first advisory with Megathrust Earthquake Attention at that time.

On Monday, tsunami advisories were issued for Miyazaki and Kochi Prefectures. A 20-centimeter tsunami was observed in Miyazaki and Nichinan in Miyazaki Prefecture, and a 10-centimeter tsunami in Muroto and Tosashimizu in Kochi Prefecture.

Damage in Miayazaki Pref.

Damage including burst water pipes and fallen rocks blocking a prefectural road was confirmed in Miyazaki Prefecture on Tuesday in the wake of Monday’s earthquake.

In the Ikime area of the prefecture, water was confirmed to be spewing out at two locations, including one near a curb on a city road. According to the Miyazaki city government, water pipes were believed to have been damaged, disrupting the water supply to two households.