South Atlantic Earthquakes
Tristan da Cunha is in an active seismic region. 400 km west of Tristan da Cunha is the Mid-Atlantic Ridge.
Here there is active sea-floor spreading as the South American and African Plates move apart. Frequent earthquakes accompany these plate movements and sub-marine volcanoes emit basalt lava, which cools rapidly into characteristic 'pillow' shapes. The active Tristan da Cunha Volcano and the extinct cones of Gough, Inaccessible and Nightingale Islands are not part of the Mid-Atlantic Ridge. Tristan is a hot-spot volcano, with magma rising from deep in the mantle. So local earthquakes may signal a subsequent volcanic eruption on the Tristan Volcano, which is some 5500 metres high from its base on the ocean floor to the top of the Peak,, and 45 km across on the ocean floor..
See The Tristan da Cunha Volcano Page for further details.

Earthquake Monitoring
On Tristan itself there are a range of scientific instruments, including seismographs - see our separate Scientific Monitoring Page for details. This station is one of many across the world monitored constantly.

The best source of information on recent earthquakes worldwide is the USGS site at ~
http://earthquake.usgs.gov/earthquakes
to discover every major earthquake world-wide
From January 2010 we aim to publish details of any local South Atlantic earthquakes and attempt to identify their tectonic situation.