Earthquakes near San Miguel through history

The deadliest was not the strongest: a magnitude 7.7 on September 7, 1915 (12 km NW of Chalatenango, El Salvador), for which NOAA records 7 deaths. NOAA’s list of significant earthquakes has 29 here, back to AD 450. NOAA records deaths in 13 of the events here, 33,204 in all. The latest on NOAA’s list is a magnitude 5.6 on December 9, 2024 (2 km SSE of Conchagua, El Salvador). NOAA’s record here begins in AD 450 with an eruption (Ilopango). It grows thinner going back: 18 of the 29 significant earthquakes NOAA lists here are from 1927 on. NOAA lists 3 tsunamis that began within 100 km of San Miguel, and 2 from elsewhere that reached it with deaths or a metre of water or more. The highest water NOAA records here was 6.3 m, on August 27, 2012. The deadliest here came on September 2, 1992 from a magnitude 7.6 earthquake (Nicaragua): NOAA’s runup records count 3 deaths within 100 km of San Miguel. NOAA lists 3 significant eruptions of 2 volcanoes within 100 km of San Miguel. The largest was Ilopango in AD 450, at 6 on the volcanic explosivity index. It killed 30,000 people by NOAA’s count.

• December 9, 2024Earthquake · M 5.62 km SSE of Conchagua, El SalvadorUSGS · NOAA NCEI
• August 27, 2012Tsunami · 6.3 m hereEl Salvador-NicaraguaNOAA NCEI · Wikipedia
• September 2, 1992Tsunami · 6.18 m hereNicaragua · 3 deaths here (NOAA)NOAA NCEI · Wikipedia
• September 7, 1915Earthquake · M 7.712 km NW of Chalatenango, El Salvador · 7 deaths (NOAA)USGS · NOAA NCEI
• May 30, 1776Earthquake · M 7.9 (est.)NOAA NCEI
• AD 450Eruption · VEI 6Ilopango · 30,000 deaths (NOAA)NOAA NCEI · Wikipedia

• An event counts for San Miguel 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