Earthquakes near Cheonan through history

The strongest was a magnitude 7, twice: in December 27 (Kwangju) and in July 89 (Kwangju). NOAA records deaths in 2 of the events here, 10 in all. The latest on NOAA’s list is a magnitude 5 on October 7, 1978 (Hongseong). NOAA’s record here begins in December 27 with an earthquake (Kwangju). NOAA lists 3 tsunamis that began within 100 km of Cheonan. The highest of them reached 1.3 m, on May 4, 2008.

• May 4, 2008Tsunami · 1.3 m highYellow SeaNOAA NCEI
• October 7, 1978Earthquake · M 5.0HongseongNOAA NCEI
• July 89Earthquake · M 7.0 (est.)KwangjuNOAA NCEI
• December 27Earthquake · M 7.0 (est.)KwangjuNOAA NCEI

• An event counts for Cheonan 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