Magnitude 6.1 earthquake shakes northern Japan

TOKYO — A magnitude 6.1 earthquake shook part of northern Japan early Monday, but no damage or casualties have been reported.

No tsunami advisory was issued by the Japan Meteorological Agency.

The quake struck 11 miles west of the town of Sarabetsu on Japan’s northernmost main island of Hokkaido at a depth of 50 miles, according to the U.S. Geological Survey. It measured the quake’s strength at 6.1 magnitude.

A week ago, a 7.7-magnitude earthquake prompted Japan to issue an advisory of a slightly higher risk of a possible megaquake for the nation’s northeastern coastal areas.