Casualties and collapsed buildings have been reported in Kyushu, the southern-most of Japan’s four major islands, after a M6.4 earthquake hit the area at 2126 local time (1226 UTC) on April 14.
The quake was “strong and shallow” according to catastrophe risk modeller AIR Worldwide, and followed by a series of aftershocks, but with no risk of a tsunami wave.
Kumamoto Prefecture is situated in the center of Kyushu and contains 14 cities. More than 8m people live within 100 km (62 miles) of the epicenter of the quake.
“Japan experiences around 20% of the world's most powerful earthquakes, but its rigid building codes and their strict enforcement mean that powerful tremors frequently do little damage, at least to engineered structures,” said Mehrdad Mahdyiar, vice president at AIR Worldwide.
“However, as initial reports of this event confirm, vulnerable structures still exist,” he added.
The Japanese government has issued a high-level alert in the southern province and alerted disaster management teams.
“In Mashiki several houses have been flattened, and occupants may be trapped inside; several fires have been noted. Roads have been damaged, and at least 10 buildings have collapsed in Kumamoto City, the capital of the prefecture,” reported AIR Worldwide.
“Elsewhere, large cracks have been reported in several structures. Walls of some houses have collapsed in the city of Ueki, and part of a city hall ceiling fell. Gas and power outages have occurred in areas close to the epicenter,” said the firm.
The US Geological Survey (USGS) has estimated the intensity of the initial earthquake at M6.2, and the Japan Meteorological Agency (JMA) has rated it at M6.4.
The depth has been initially estimated by the USGS as 23.3km (14.4 miles) and by the JMA as 10km (6.2 miles).
Shaking started modestly, grew more violent, and lasted about 30 seconds, noted AIR Worldwide.
“The Sanyo Shinkansen “bullet train” service briefly lost power and has been suspended on Kyushu as a precaution. The Kyushu Electric Company reports no issues at the Genkai or Sendai nuclear power plants on Kyushu or at the shut-down Ikata plant on nearby Shikoku,” added AIR Worldwide.