One of the most powerful earthquakes to rock the Kansai region in decades struck Osaka and neighboring prefectures Monday morning, leaving at least four people dead and more than 300 injured.

The earthquake, which had a magnitude of 6.1 and registered lower 6 on the Japanese intensity scale to 7, hit at 7:58 a.m. at a depth of about 13 km under northern Osaka, the Meteorological Agency said. No tsunami warning was issued.

The quake literally woke the Kansai region and underscored the fact that the region remains just as vulnerable as other parts of Japan that have been more seismically active since the magnitude 7.3 Great Hanshin Earthquake killed 6,434 people and left Kobe devastated in 1995.