Dozens of small shallow-focus quakes hit Nagano Prefecture and its surrounding regions on Tuesday as the weather agency issued an emergency alert for possible strong temblors.

The largest of the quakes, measuring a magnitude 5.3 and a 4 on Japan's intensity scale, hit Takayama in Gifu Prefecture at 1:13 p.m. The city of Takayama said no damage has been confirmed. There were no worries for tsunami.

More than 30 quakes registering 1 to 3 on the Japanese earthquake intensity scale of 7 have been observed in the areas since dawn on Tuesday. Though the magnitude is not large, shallow quakes can cause disproportionately intense shaking.

A total 285 earthquakes that can be felt hit the same areas between Aug. 3 and Nov. 3 in 1998 due to bedrock distortion caused by the diving of the Pacific plate underneath a continental plate. The Japan Meteorological Agency said it is calling on residents to remain alert as a similar mechanism may be behind the latest quakes.