Earthquake Offshore of Kushiro on July 21

On July 21, 2024 at 13:27, an M5.4 earthquake (maximum seismic intensity 3) occurred at a depth of 28 km, offshore of Kushiro. The focal mechanism (CMT solution) of this earthquake was a reverse fault type with a compression axis in an NW-SE direction. The earthquake occurred at the boundary between the Pacific Plate and the continental plate.
For the seismic activity since October 2001, earthquakes of M5.0 or over have sometimes occurred in the vicinity of the hypocenter of the recent earthquake (Area b): the M7.1 earthquake of November 29, 2004 (maximum seismic intensity 5 Upper) resulted in 52 injured, one house completely destroyed and four partially destroyed (according to the Fire and Disaster Management Agency (FDMA), Ministry of Internal Affairs and Communications).
For the seismic activity since 1919, there have been three earthquakes of M7.0 or over in the area (Area c) around the epicenter of the recent earthquake: the largest earthquake was "the Earthquake off the Coast of Nemuro Peninsula on June 17, 1973" (M7.4, maximum seismic intensity 5), which caused a tsunami of 280 cm (maximum height above normal tide level) in Hanasaki, Nemuro City. It also caused damage to 28 injured people and 5,153 residential buildings. (According to "Disaster Records in 1973/1974 Hokkaido").

Japan Meteorological Agency
[Evaluation of Seismic Activities for July 2024 (August 9, 2024)]