Earthquakes near Tomakomai through history

The deadliest was not the strongest: an estimated magnitude 6.5 on July 31, 1640 (Uchiura Bay), for which NOAA records 700 deaths. NOAA’s list of significant earthquakes has 12 here, back to 1611. NOAA records deaths in 18 of the events here, 3,000 in all. The latest on NOAA’s list is a magnitude 7.6 on December 8, 2025 (2025 Aomori Prefecture, Japan Earthquake). NOAA’s record here begins on December 2, 1611 with a tsunami (Sanriku). It grows thinner going back: 9 of the 12 significant earthquakes NOAA lists here are from 1927 on. NOAA lists 3 tsunamis that began within 100 km of Tomakomai, and 12 from elsewhere that reached it with deaths or a metre of water or more. The highest water NOAA records here was 4.17 m, on March 11, 2011. The deadliest here came on December 2, 1611 from a magnitude 8.1 earthquake (Sanriku): NOAA’s runup records count 1,783 deaths within 100 km of Tomakomai. NOAA lists 13 significant eruptions of 4 volcanoes within 100 km of Tomakomai. The largest was Hokkaido-Komagatake on July 31, 1640, at 5 on the volcanic explosivity index. It killed 700 people by NOAA’s count.

• December 8, 2025Earthquake · M 7.62025 Aomori Prefecture, Japan EarthquakeUSGS · NOAA NCEI · Wikipedia
• March 11, 2011Tsunami · 4.17 m hereHonshu IslandNOAA NCEI · Wikipedia
• May 16, 1968Earthquake · M 7.970 km S of Honchō, JapanUSGS · NOAA NCEI · Wikipedia
• March 4, 1952Earthquake · M 8.11952 Tokachi-Oki Earthquake · 33 deaths (NOAA)USGS · NOAA NCEI
• July 31, 1640Earthquake · M 6.5 (est.)Uchiura Bay · 700 deaths (NOAA)NOAA NCEI
• July 31, 1640Eruption · VEI 5Hokkaido-Komagatake · 700 deaths (NOAA)NOAA NCEI · Wikipedia
• December 2, 1611Tsunami · 25 m highSanriku · 1,783 deaths here (NOAA)NOAA NCEI · Wikipedia

• An event counts for Tomakomai when it began within 100 km of its centre, or 200 km for an earthquake of magnitude 7 or more. Damage can reach further.
• USGS counts here start at magnitude 6: the catalogue’s smaller quakes thin out going back, where few instruments listened.
• NOAA lists significant events only: earthquakes that killed, did about $1 million of damage, reached magnitude 7.5 or intensity X, or raised a tsunami, and eruptions and tsunamis by like measures. Magnitudes before 1900 are its estimates from written accounts.
• Deaths are NOAA’s total for each event, wherever people died, its tsunami and fires included. A tsunami counts the dead its runup records give for this place: NOAA’s total for a tsunami includes its source quake’s.
• A tsunami from elsewhere counts where one of its runups killed or rose a metre or more.
• Counted to October 19, 2026, as is the map. The last 30 days ask USGS again.

How the layers work, where their data comes from and what they can’t tell you: Earthquakes, live, The world through history