Tsunami advisories issued briefly for northern Japan

All the advisories were lifted at 2:05 pm after minor tsunami waves were observed in some municipalities, according to the Japan Meteorological Agency.

Around 11:44 am, a quake with an estimated magnitude of 6.9 occurred off Aomori, logging 4 on Japan's seismic intensity scale in 38 municipalities in five prefectures, including Hokkaido's Hakodate, Aomori's Hachinohe and Iwate's Morioka. The intensity is the sixth-highest level on the 10-point scale.

In Hokkaido, a 20-centimeter tsunami was observed at 12:35 pm in the town of Erimo. Tsunami waves reached up to 20 centimeters also at a port in Hachinohe.

The quake's focus, estimated to be 17 kilometers deep, was just east of that of Monday's 7.5-magnitude temblor, which shook Aomori, Hokkaido and other prefectures and triggered tsunami waves.

Friday's quake occurred at a point between the oceanic and continental plates, as with the Monday quake.

In response to Monday's quake, the agency issued what it calls a subsequent quake advisory warning of a possible further quake off the Hokkaido and Sanriku regions from northern to northeastern Japan.

This advisory will remain in place until the end of Monday.

The Friday quake is different from what is expected in the advisory, which warns of an 8-magnitude or even bigger temblor, agency official Masashi Kiyomoto said, adding that the agency will not extend the period of the advisory.

"Seismic activities remain strong off the eastern coast of Aomori Prefecture, so we want residents to watch out for a quake with an intensity of upper 6 or higher and tsunami," he added.