Japan’s northeastern coast was rattled by a Magnitude 6.7 earthquake on Friday, just days after a stronger tremor struck the same region The Japan Meteorological Agency (JMA) issued a Tsunami Advisory for coastal communities, urging residents to move away from the sea.
The Latest Tremor: Friday’s Event
The 6.7 magnitude quake struck at 11:44 a.m. local time (0244 GMT) off the east coast of Aomori prefecture, which is on the north of Honshu, Japan’s main island.
- Magnitude: 6.7
- Advisory Issued For: Pacific coast of Hokkaido, Aomori, Iwate, and Miyagi prefectures.
- Tsunami Expectation: Waves of up to 1 KM were initially possible.
- Current Status: The tsunami advisory was later lifted after only small waves, up to 20 centimeters were observed in Hokkaido and Aomori.
- Damage Report: No immediate reports of casualties or significant property damage were available following this quake.
Following Monday’s M7.5 Quake
Friday’s event follows a powerful Magnitude 7.5 earthquake that rocked the same coastal region earlier this week.
- Casualties: The Monday quake off the coast of Aomori injured at least 34 people (other reports noted a figure rising to 51).
- Tsunami Observed: A tsunami measuring up to was measured at Kuji port in Iwate prefecture.19
- Disruptions: The earlier quake caused light structural damage, cracked roads, and temporarily knocked out power for hundreds of homes.
- Long-Term Warning: Following the 7.5 magnitude quake, the JMA issued an unusual advisory for the region—from Chiba, east of Tokyo, to Hokkaido—warning of an increased risk of a Magnitude 8-level quake and possible tsunami for the subsequent week.
Tsunami Advisory vs. Warning
The Tsunami Advisory issued by the JMA is a lower level of alert compared to a Tsunami Warning:
| Alert Level | Estimated Max Tsunami Height | Expected Damage and Action |
| Tsunami Advisory | Up to $1 \text{ meter}$ | Strong currents expected in the sea. Small vessels may capsize. Action: Get out of the water and leave coastal areas immediately. |
| Tsunami Warning | Up to $3 \text{ meters}$ | Buildings in low-lying areas will be flooded. Action: Evacuate immediately to high ground or an evacuation building. |
| Major Tsunami Warning | Greater than $3 \text{ meters}$ | Wooden structures are expected to be destroyed. Action: Evacuate immediately. |
This coastal area remains highly seismically active, tragically recalling the 2011 Magnitude 9.0 quake and tsunami that resulted in nearly 20,000 deaths and the Fukushima Daiichi nuclear power plant disaster.