A magnitude 6.9 earthquake triggered a for parts of Hokkaido as well as the coasts of Aomori, Iwate and Miyagi prefectures on Friday. The advisory was later lifted.

The quake struck at 11:44 a.m., registering shindo 4 in some areas on Japan¡¯s seismic intensity scale of 1 to 7.

Waves of up to 1 meter in height are possible in areas under the advisory, according to the Japan Meteorological Agency (JMA). Some shores in Hokkaido and Aomori have already observed waves of around 20 centimeters in height, according to NHK. The advisory was lifted at around 2 p.m.

A tsunami advisory, at a level lower than a tsunami warning, urges those in the area to stay away from the ocean. Evacuation is not required under an advisory.

The JMA registered a seismic intensity of 4 in parts of Hokkaido, Aomori, Iwate, Miyagi and Akita prefectures.

The shaking occurred in the same region as the earthquake that occurred on Monday night but was less intense, the agency said. It is not unusual for such quakes to follow.

As of 1 p.m. on Friday, there have been 31 earthquakes exceeding shindo 1 since the major quake on Monday. Among them, the one that occurred just before noon on Friday was the biggest.

The quake occurred at a depth of approximately 17 kilometers, shallower than the one earlier this week, which occurred at a depth of 50 km.

Monday¡¯s magnitude 7.5 earthquake left more than 30 injured and initially triggered a tsunami warning.

A subsequent quake advisory ¡ª which is issued following a quake with a moment magnitude of 7 or larger ¡ª was issued in the region, meaning that the likelihood of a larger earthquake is relatively higher for the week following the original tremor.

The moment magnitude for the quake on Friday was 6.6, so it has not raised a subsequent quake advisory.

The JMA urged people to reassess their disaster prevention plans, although the agency is not currently requesting evacuation.

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