2024 Hyūga-nada earthquake

2024 Hyūga-nada earthquake

USGS ShakeMap
UTC time	2024-08-08 07:42:55
USGS-ANSS	ComCat
Local date	8 August 2024 (2024-08-08)
Local time	16:42:55 JST
Magnitude	7.1 MJMA 7.1 Mw
Depth	25.0 km (16 mi)
Epicenter	31.719°N 131.527°E / 31.719; 131.527
Areas affected	Kyushu, Japan
Max. intensity	JMA 6− VIII (Severe)
Peak acceleration	0.45 g
Peak velocity	40.75 cm/s
Tsunami	50 cm (1.6 ft)
Casualties	16 injured

On 8 August 2024, at 16:42 JST (07:42 UTC), a magnitude 7.1 earthquake happened in Miyazaki Prefecture, Kyushu, Japan, 20 km (12 mi) northeast of Nichinan.^[1]

Tectonic setting

The Hyūga Sea is in the southwestern part of the Nankai Trough, where the Philippine Sea Plate moves under the Eurasian Plate. This area has had big earthquakes in 1968 and 1996. The Hyūga Sea is a zone between two different parts of the Nankai Trough.^[2] Below the sea floor, there are small earthquakes and slow movements in the deeper part of the zone.^[3]

Earthquake

The United States Geological Survey reported a magnitude (M_w ) of 7.1, at a depth of 25 km (16 mi) and a maximum Modified Mercalli intensity of VII (Very Strong).^[1] The United States Geological Survey first reported two earthquakes with magnitudes 7.1 and 6.9, but then fixed it later.^[4]

Locations with a seismic intensity of Shindo 5− and higher^[5]

Intensity	Prefecture	Locations
6−	Miyazaki	Nichinan
5+	Miyazaki	Miyazaki, Kushima, Miyakonojō
	Kagoshima	Ōsaki
5−	Miyazaki	Mimata, Kunitomi, Shintomi, Takanabe, Takaharu, Kobayashi
	Kagoshima	Soo, Kanoya, Kimotsuki, Higashikushira, Tarumizu, Kirishima, Kagoshima, Aira

Tsunami

After the earthquake, a tsunami advisory was issued for Kōchi, Ehime, Oita, Miyazaki, and Kagoshima Prefectures,^[6] warning of waves up to 3.3 feet. In Miyazaki, waves were 50 cm (1.6 ft), and in Kōchi, they were 20 cm (0.66 ft).^[6] The advisories were lifted at 20:00 JST.^[7]

Impact

The earthquake injured at least 16 people, with two seriously injured,^[8] and destroyed two houses in Kyushu.^[9] In Miyazaki Prefecture, five people were injured, with two in Nichinan, two in Miyazaki, and one in Miyakonojō, with damage to Obi Castle Town, a road was closed because of rocks falling, a house partly fell down, and Miyazaki Airport had little bit broken, with some flight cancellations and delays. Water pipes leaked in Kushima. In Kagoshima Prefecture, two people were injured, several walls and a two-story house collapsed, roads were raised in Ōsaki, and there was a landslide in Shibushi. Two people were also injured in Kumamoto Prefecture.^{[10][11][12][13]}

Shinkansen trains on the Kyushu and Nishi Kyushu lines stopped running. The Ikata and Sendai Nuclear Power Plants near the epicenter had no problems.^[6]

Aftermath

After the earthquake, the Japan Meteorological Agency said that there was a higher chance of a very big earthquake along the Nankai Trough. This was the first advisory like this, but they said it wasn't happening soon.^[4][14] They told people in affected areas to follow safety tips from the government.^[7] Because of this, the Central Japan Railway made trains go slower for a week,^[6] and Prime Minister Fumio Kishida canceled his trip to Central Asia on 9 August.^[15]

Related pages

• 2024 Noto earthquake
• 2016 Kumamoto earthquakes

References

1. National Earthquake Information Center (8 August 2024). "M 7.1 - 20 km NE of Nichinan, Japan". United States Geological Survey. Retrieved 8 August 2024.
2. Asano, Youichi; Obara, Kazushige; Matsuzawa, Takanori; Hirose, Hitoshi; Ito, Yoshihiro (2015). "Possible shallow slow slip events in Hyuga-nada, Nankai subduction zone, inferred from migration of very low frequency earthquakes". Geophysical Research Letters. 42 (12): 331–338. doi:10.1002/2014GL062165.
3. Ioki, Kei; Yamashita, Yusuke; Kase, Yoshihiro (2023). "Effects of the Tsunami Generated by the 1662 Hyuga-Nada Earthquake off Miyazaki Prefecture, Japan". Pure and Applied Geophysics. 180 (6): 1897–1907. doi:10.1007/s00024-022-03198-3. hdl:2433/284057.
4. Tomohiro Osaki (8 August 2024). "7.1-magnitude Earthquake Hits Off Japan". Barron's. Retrieved 8 August 2024.
5. "Earthquake information". Japan Meteorological Agency. 8 August 2024. Retrieved 8 August 2024.
6. "M7.1 quake hits southwestern Japan, 0.5-meter tsunami observed". Kyodo News. 8 August 2024. Retrieved 8 August 2024.
7. "Megaquake advisory issued, tsunami advisories lifted". NHK. 8 August 2024. Retrieved 9 August 2024.
8. "Kyushu escapes major damage from magnitude 7.1 earthquake". Japan Times. 9 August 2024. Retrieved 9 August 2024.
9. "震度６弱地震で負傷者１２人と防災相". Ehime Shimbun (in Japanese). 8 August 2024. Retrieved 8 August 2024.
10. 【被害】宮崎 日南市で2人けが 各地で住宅被害も [Damage: Two people were injured in Nichinan City, Miyazaki, Japan, and damage to houses in various areas.] (in Japanese). NHK. 8 August 2024. Retrieved 9 August 2024.
11. 最大震度6弱を観測 宮崎県内の地震被害まとめ（午後６時半時点） [Summary of earthquake damage in Miyazaki Prefecture (as of 6:30 p.m.), with a maximum intensity of 6] (in Japanese). TBS. 8 August 2024. Retrieved 9 August 2024.
12. Yamaguchi, Mari (8 August 2024). "A powerful quake hits off Japan's coast, causing minor injuries but prompting new concerns". apnews.com. Retrieved 9 August 2024.
13. "Japan issues first 'megaquake' warning after 7.1-magnitude temblor". NBC News. 9 August 2024. Retrieved 9 August 2024.
14. "Japan sees higher-than-usual risk of megaquake off Pacific Coast". Kyodo News. 8 August 2024. Retrieved 8 August 2024.
15. "Japan PM scraps overseas trip after 'megaquake' advisory". France 24. AFP. 9 August 2024. Retrieved 9 August 2024.