Kumamoto - A powerful magnitude 7.1 earthquake struck Kumamoto Prefecture at around 4:27 p.m. on July 28, registering the highest level of 7 on Japan's seismic intensity scale and prompting a tsunami advisory for coastal areas.
The earthquake was centered in the Kumamoto region of Kumamoto Prefecture at an estimated depth of about 10 kilometers.
The Japan Meteorological Agency issued the tsunami advisory at 4:29 p.m. for the coasts of the Ariake and Yatsushiro seas, where waves of up to 1 meter were forecast. People near the coast were urged to move away from the shoreline and continue monitoring official information.
The shallow earthquake occurred within the continental crust and was believed to have involved strike-slip fault movement. Although the precise extent of the fault rupture was not immediately clear, the movement may have affected an area extending toward the seabed, leading authorities to issue the tsunami advisory.
The epicenter was relatively close to the area affected by the series of powerful Kumamoto earthquakes in April 2016. Seismic activity in the region is associated with active fault systems extending through Kumamoto Prefecture, and the latest earthquake was believed to have occurred as accumulated strain caused part of the fault system to move.
The 2016 Kumamoto earthquake sequence included a magnitude 6.5 earthquake on April 14 followed by a magnitude 7.3 earthquake on April 16. Mashiki was struck by seismic intensity 7 shaking twice during the sequence.
The experience led authorities to avoid treating the first large earthquake simply as a main shock followed by smaller aftershocks, as another earthquake of comparable or greater strength can occur during the same sequence.
Similar continued activity cannot be ruled out following the July 28 earthquake, and residents were warned that movement along the fault responsible for the latest tremor could continue.
Initial reports from residents indicated that household objects had fallen during the shaking. Damage similar to that caused by the 2016 earthquakes may already have occurred in some areas, although the full extent was not immediately known.
Residents were urged to watch for damaged or unstable buildings, avoid coastal areas covered by the tsunami advisory and closely follow information from disaster management authorities.
Video recorded in Kumamoto City captured the moment the powerful earthquake struck.
Source: TBS
