Another Magnitude 6.7 Earthquake Strikes Off Aomori, Japan...Tsunami Advisory Issued

At approximately 11:44 a.m. on December 12, a magnitude 6.7 earthquake was estimated to have occurred off the coast of Aomori Prefecture in northeastern Honshu, Japan.

According to Kyodo News, NHK, and other sources, the Japan Meteorological Agency initially announced the earthquake's magnitude as 6.5, but later revised it upward to 6.7. The depth of the epicenter was about 20 kilometers.

On the 8th, a magnitude 7.5 earthquake occurred in Aomori Prefecture. Photo by AFP Yonhap News

The offshore area of Aomori Prefecture is the same region where a powerful magnitude 7.5 earthquake struck on the night of December 8.

The Japan Meteorological Agency issued a tsunami advisory for the southern coast of Hokkaido and the Pacific coast of northeastern Honshu. In Japan, a tsunami advisory is issued when a tsunami with a height of 0.2 to 1 meter is expected. On this day, a tsunami with a maximum height of 20 centimeters was observed at Hachinohe Port in Aomori Prefecture and at Erimo Town in Hokkaido.

As a result of this earthquake, seismic intensity level 4 shaking was detected in parts of Aomori, Iwate, Miyagi, Akita Prefectures, and some areas of Hokkaido.

Unlike magnitude, which represents the absolute strength of an earthquake, seismic intensity as defined by the Japan Meteorological Agency is a relative measure that quantifies how people in the affected area feel the earthquake and the extent to which surrounding objects shake. Seismic intensity level 4 indicates shaking strong enough to startle most people and cause ceiling lights to swing noticeably.

No abnormalities were detected at the Higashidori Nuclear Power Plant or spent nuclear fuel facilities in Aomori Prefecture, nor at the Onagawa Nuclear Power Plant in Miyagi Prefecture.

Kyodo News also reported that there is no risk of a transmission tower in Hachinohe City, Aomori Prefecture, which was partially damaged by the strong earthquake on December 8, collapsing.

Since the strong earthquake on December 8, the Japanese government has issued, for the first time, a "Secondary Earthquake Advisory for Offshore Areas of Hokkaido and Sanriku." This advisory will remain in effect until midnight on December 16.

A secondary earthquake advisory is issued when a magnitude 7.0 or greater earthquake occurs in an epicentral region along the Japan Trench or Kuril Trench, where large earthquakes are expected, indicating a higher-than-usual likelihood of a major earthquake. However, since the magnitude of this earthquake did not reach 7.0, the Japan Meteorological Agency did not extend the duration of the secondary earthquake advisory.

At a press conference, a representative from the Japan Meteorological Agency stated, "This earthquake occurred within the area of seismic activity triggered by the December 8 earthquake," and advised continued caution in regions that experienced strong shaking during the earlier event. The official also urged, "Please refrain from entering the sea or approaching the coastline until the tsunami advisory is lifted."

Prime Minister Sanae Takaichi stated, "While paying close attention to information from the Meteorological Agency and local governments, please reconfirm earthquake preparedness measures such as identifying safe evacuation sites and routes and securing furniture." She added, "Please maintain readiness to evacuate immediately if you feel shaking, while continuing social and economic activities."