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Nankai Trough Earthquake Related Explanatory Information （ No.1 ）.

Nankai Trough Earthquake Related Explanatory Information （ No.1 ）

■ Date and Time ： 15:30, August 9, 2024
■ Summary ：

Earthquake with epicenter at Hyuga-nada at 16:43 on August 8 A magnitude 7 ． 1 earthquake occurred. With the occurrence of this earthquake, the possibility of a large-scale earthquake in the assumed epicenter area of the Nankai Trough earthquake was considered to be relatively higher than normal, so at 19:15 on August 8, we issued a Nankai Trough Earthquake Temporary Information （ Giant Earthquake Warning ）. Please continue to take disaster prevention measures in response to calls from the government and local governments.



A magnitude 7 ． 1 （ moment magnitude 7 ． 0 ） earthquake occurred at 16:43 on August 8, centered in the Hyuga Sea. Seismic activity near the epicenter of this earthquake has remained active since then.
The number of earthquakes of intensity 1 or higher observed in the assumed epicenter area of the Nankai Trough earthquake from 16:00 on August 8 to 14:00 today （ September 9 ） （ The preliminary report ） is as follows.
8 times from 16:00 to 24:00 on the 8th （ Lower intensity 6 ： 1 time, intensity 2 ： 2 times, intensity 1 ： 5 times ）
6 times from 00:00 to 14:00 on the 9th （ Intensity 3 ： 1 time, intensity 2 ： 2 times, intensity 1 ： 3 times ）
Also, at strain stations, step-like changes associated with a magnitude 7 ． 1 earthquake have been observed, but so far no changes other than those normally seen after an earthquake have been observed.

As a result of studying the relationship between the August 8 earthquake and the Nankai Trough earthquake, the possibility of a large-scale earthquake in the assumed epicenter area of the Nankai Trough earthquake is considered to be relatively higher than under normal conditions, and so at 19:15 on August 8, we issued a Nankai Trough earthquake temporary information （ A huge earthquake warning ） was issued.
The government is calling on the Nankai Trough Earthquake Disaster Prevention Promotion Areas to reconfirm their daily earthquake preparedness and be ready to evacuate immediately if they feel a tremor for one week after the earthquake on August 8. Please continue to take disaster prevention measures in response to calls from the government and local governments.
The JMA will continue to carefully monitor crustal activity along the Nankai Trough.

*Moment magnitude is the magnitude obtained by closely examining the scale of displacement of the epicenter fault. It may be different from the magnitude reported by the Japan Meteorological Agency in earthquake information.


We will continue to announce the status of crustal activity and other information in the "Nankai Trough Earthquake Related Information. The next release is scheduled for around 15:30 on the 10th.
We will announce any new changes as they are observed.


[Distributed by]
Funabashi City Emergency Management Division

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