KAGOSHIMA -- A powerful earthquake rocked Kyushu late May 13, injuring 27 people, officials said.

The quake struck at 2:38 p.m. and had an estimated magnitude of 6.1 on the Richter scale, according to the Meteorological Agency. Its focus was estimated at 20 km beneath the ground of the Satsuma area in northwest Kagoshima Prefecture.

In Sendai, Kagoshima Prefecture, the temblor was in the lower 6 range on the Japanese intensity scale of 7 agency, according to agency officials. They said there was no threat of tidal waves. It is the first time that a quake of such high intensity has been recorded since the Japanese seismic scale was revised in October.

By 9:00 p.m., 27 people in the towns of Tsuruda and Miyanojo in the northwest Kagoshima had reported injuries, and power to Sendai City Hall were temporarily cut, Kagoshima Prefectural Police said. The earthquake also temporarily cut power to about 79,000 homes in the northwestern part of the prefecture, Kyushu Electric Power Co. officials said. But a nuclear power plant situated in Sendai was unaffected by the quake and continued to operate as usual, they said.