Earthquakes in British Indian Ocean Territory, 2017–2026

2020 had the most magnitude 4.5+ earthquakes: 5 of the 14.

• October 7, 2026Earthquake · M 5.2Chagos Archipelago regionUSGS
• January 16, 2025Earthquake · M 4.9Chagos Archipelago regionUSGS
• July 15, 2022Earthquake · M 4.9Chagos Archipelago regionUSGS
• July 27, 2020Earthquake · M 5.3Chagos Archipelago regionUSGS
• January 23, 2020Earthquake · M 4.8Chagos Archipelago regionUSGS

• An event counts for British Indian Ocean Territory when it began inside its borders, or at sea within 100 km of its coast (so one can count for two neighbours), or further out, up to 300 km, where British Indian Ocean Territory is the nearest country.
• USGS counts are its ComCat catalogue’s earthquakes of magnitude 4.5 or more, aftershocks included.
• 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.
• The map frames the box around British Indian Ocean Territory, its neighbours’ quakes included, so its count runs higher than this page’s.
• 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