A 7.6-magnitude earthquake struck Japan’s northern coast of Sanriku late on 8 December, with Japanese media reporting 30 people injured and the country’s meteorological agency issuing tsunami warnings that were downgraded to advisories hours later.
The epicentre of the quake, which hit at 11:15 p.m. local time, was located at 80 kilometres off the coast of Aomori prefecture at a depth of 54 km, according to the Japan Meteorological Agency (JMA). The United States Geological Survey (USGS) recorded the temblor at a depth of 44 km.
The USGS estimated a low chance of casualties with a 38% chance of losses between US$1m and US$10m, a 29% chance of losses between US$10m and US$100m. It also reported a 23% chance of economic losses below US$1m and a 9% chance of losses between US$100m and US$1bn.
The JMA issued tsunami alerts for the first time for the prefectures of Hokkaido, Aomori, and Iwate. This prompted 90,000 residents to flee their homes and evacuate.
Tsunamis from 20 centimetres to 70 cm high were observed at several ports, according to the agency, which initially said a tsunami as high as 3 metres could hit the country’s northeastern coast following the quake.
Early on 9 December, the JMA lifted the warnings but kept lower-grade advisories in effect for parts of northern Japan for several hours before eventually cancelling them, according to local media.
Kyodo News reported some 2,700 homes in Aomori were without power and numerous fire incidents.
“I am hearing that there have been seven injuries reported,” Prime Minister Sanae Takaichi told journalists covering the quake early morning on Tuesday. “The government asks residents to continue social and economic activities while maintaining a readiness to evacuate immediately if any shaking is felt.”
The quake was also felt in the northern city of Sapporo, where residents were alerted by alarms that rang on their smartphones.
Following the temblor, the Shinkansen bullet-train service was suspended between Fukushima and Aomori. Some services were expected to resume late morning on Tuesday, the operator posted online.
Japan, an archipelago, is home to around 125 million people and experiences around 1,500 earthquakes every year. The most recent magnitude 7 earthquake struck in the Hyūga Sea off the coast of Miyazaki Prefecture, Kyushu on 8 August 2024, which injured 16 people.
In March 2011, a magnitude 9.0 undersea megathrust earthquake rocked the country’s Tohoku region and triggered a tsunami that left 18,500 people dead or missing and caused a meltdown at the Fukushima nuclear plant.
The quake also comes as S&P Global Ratings said last month that the risk of large earthquakes in Japan could lead to insurance claims that exceed non-life insurers’ annual earnings, with losses from a Nankai Trough or Tokyo megaquake potentially far outstripping those from the 2011 Great East Japan Earthquake.
The agency notes that non-life and life insurers are increasing their use of reinsurance and stress testing, but warns that a major event could pressure insurer and sovereign credit ratings.
