1980 Azores earthquake
  Terceira
Graciosa
São Jorge
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| Date | January 1, 1980 |
|---|---|
| Origin time | 15:43:39 UTC-1 |
| Magnitude | 7.2 Mw |
| Depth | 10 kilometres (6 mi) |
| Epicenter | 38°49′N 27°47′W / 38.81°N 27.78°W |
| Type | Strike-slip |
| Areas affected |
Portugal Azores |
| Tsunami | A small tsunami was registered in Angra do Heroismo |
| Casualties | 61 confirmed dead, 400 injured |
Striking the Autonomous Region of Azores on 1 January, the 1980 Azores Island earthquake killed 61 people and injured over 400, causing severe damage on the islands of Terceira and São Jorge. Measuring 7.2 on the Richter scale, it also shook the islands of Pico and Faial, and resulted from a strike slip fracture, typical of other historical Azorean earthquakes.
In response to the earthquake, Portuguese president António Ramalho Eanes announced three days of national mourning, while relief efforts, initiated by agents of the local Air Force, were soon accompanied by government-supported agencies.
In 1950, another strong earthquake had rocked the Azores Islands region, and this was the largest earthquake since.
Volcanic in origin, the Azores lie in a tectonically complex area on either side of the Mid-Atlantic Ridge, between the European, Eurasian and African plate boundaries, forming their own microplate. The 1980 earthquake was the result of movement along the northwest to southeast trending strike-slip fault.
After aftershocks from the quake had concluded, examination took place, producing a focal solution to the small events. Movement of these shocks was similar to that of previous earthquakes around the Azores. For these earthquakes, scientists had determined that the conjugate nodal plane was responsible, seeing shearing on the right-lateral (dextral) side. All faulting in this area is strike-slip-oriented, and on a rather large scale. Because of this research, information now points towards Azores volcanism being controlled by earthquake movement.
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