Two earthquakes measuring 4.5 and 3.8 magnitude struck São Miguel island in the Azores within five minutes on Thursday morning. The Portuguese Institute for Sea and Atmosphere (Instituto Português do Mar e da Atmosfera or IPMA) reported 75 tremors since 20 October originating near the Hirondelle Basin, four of which were felt by residents. IPMA noted that the area periodically experiences seismic swarms and continues to monitor regional fault activity.
Azores Records 75 Earthquakes Amid Rising Seismic Activity in São...
Thursday, 29 October 2026AI summary
Context & Explainers
IPMA (Instituto Português do Mar e da Atmosfera) is Portugal's national authority for weather, ocean, and climate monitoring. It produces weather forecasts, issues severe weather warnings, monitors seismic activity, and provides marine and atmospheric data.
IPMA uses a four-level color-coded warning system: green (no risk), yellow (potential risk), orange (moderate-to-high risk), and red (extreme risk). These warnings cover conditions such as heavy rain, strong winds, extreme heat, cold snaps, rough seas, and snow.
Residents should monitor IPMA forecasts during storm season (typically October–March) and heatwaves (July–August). IPMA bulletins are used by civil protection authorities, transport operators, and local councils to make decisions about road closures, school suspensions, and evacuation orders.
Website: ipma.pt
5 sources
- Abnormal heat coming to PortugalThe Portugal News ·
- Seismic activity on São Miguel occurs in an area that periodically experiences crisescmjornal.pt ·
- Seismic activity on São Miguel in an area where crises periodically occurrtp.pt ·
- 75 earthquakes in São Miguel since October 20thobservador.pt ·
- Earthquakes of 4.5 and 3.8 magnitude felt in São Miguel five minutes apart. 75 tremors recorded since October 20thdn.pt ·
