Seismic activity in the Azores

On October 3, 2026, Santa Maria Island in the Azores experienced a 3.7 magnitude earthquake. The tremor, recorded at 10:54 local time, had an epicenter approximately 20 kilometers northeast of Santa Bárbara. The Azores Seismovulcanological Information and Surveillance Center (CIVISA) reported a maximum intensity of III on the Modified Mercalli Scale in Vila do Porto and Almagreira, characterized as weak shaking felt indoors. Following the seismic activity, heavy rainfall in the region led to landslides, overflowing streams, and road obstructions on the island. The Mayor of Vila do Porto, Bárbara Chaves, stated that no injuries or displaced persons were reported, though one residence experienced flooding. Local emergency services and civil protection departments were deployed to clear roads and streams. The Portuguese Institute for the Sea and Atmosphere (IPMA) issued a yellow weather warning for Santa Maria and São Miguel islands due to forecasts of heavy precipitation and potential thunderstorms. On October 20, 2026, a moderate earthquake with a magnitude between 5.1 and 5.2 struck the island of São Miguel at 18:07 local time. The epicenter was located approximately 40 kilometers west of Ginetes, near the Hirondelle Trench, a submarine depression delimited by tectonic faults between São Miguel and Terceira. IPMA and the Regional Civil Protection and Firefighters Service of the Azores (SRPCBA) reported no casualties or material damage, though intensity levels reached V/VI on the Modified Mercalli scale in Ponta Delgada. Since the main event, CIVISA has recorded nearly one hundred aftershocks, some exceeding a magnitude of 3. While activity showed a decreasing trend overnight, experts warned that the system may take time to reach equilibrium and further tremors remain possible. Additional seismic activity, including a magnitude 4.4 tremor, has been recorded in the same region near the Hirondelle Trench.