On 8 August 2024, at 16:42:55 JST (07:42 UTC), a Mw 7.1 earthquake struck in the Hyūga Sea off the coast of Miyazaki Prefecture, Kyushu, Japan, 20 km (12 mi) northeast of Nichinan.

Beneath the east coast of Kyushu, on the deeper part of the subduction zone, slow slip events were detected between 1996 and 2017.

[7] The United States Geological Survey reported a magnitude (Mww ) of 7.1, at a depth of 25 km (16 mi) and a maximum Modified Mercalli intensity of VIII (Severe).

[10] On August 9, 2024, at 7:57pm JST, a 5.3MJMA earthquake struck 820 km (510 mi) away in western Kanagawa Prefecture,[12] causing tremors recorded as a 5- on the JMA seismic intensity scale and injuring 3.

In Kagoshima Prefecture, four people were injured,[23] several walls and a two-story house collapsed, and roads were raised in Ōsaki.

[31] The JMA called for those living in areas expected to be impacted by a Nankai megathrust earthquake to follow disaster prevention measures provided by the government,[32] and advised households with children, elderly, or physically disabled individuals to consider voluntarily evacuating.

[33] The Japanese government designated 707 municipalities in 29 prefectures, including Yokohama, Shizuoka, Hamamatsu, Nagoya, Kyoto, Osaka, Kobe, Okayama, Hiroshima, all of Shikoku, Miyazaki, and parts of Okinawa, as areas at risk of being affected by a strong tremor with an intensity of lower 6 or higher and a tsunami with a height of more than three meters.

[35] In response, the Central Japan Railway Company ordered trains at the Tokaido Shinkansen line to run at a slower pace for a week,[20] while Prime Minister Fumio Kishida cancelled a scheduled trip to Central Asia on 9 August[36] as part of government preparations for its possible occurrence.