Resulting from a strike slip fracture, typical of other historical Azorean earthquakes, and measuring 6.9 on the moment magnitude scale, it also shook the islands of Pico and Faial.

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.

[2] Volcanic in origin, the Azores lie in a tectonically complex area on either side of the Mid-Atlantic Ridge, between the European, American and African plate boundaries, forming their own microplate.

For these earthquakes, scientists had determined that the conjugate nodal plane was responsible, seeing shearing in the right-lateral (dextral) direction.

[7] According to local reports, roughly 70% of the houses on Terceira were completely demolished, including the historic quarter of the island capital, Angra do Heroísmo.

[2] United States Navy and Air Force personnel stationed at Lajes functioned as disaster relief workers,[2] sheltering as many as 150 families.

The Portuguese president, António Ramalho Eanes, flew in on a plane accompanied by medical personnel and supplies (such as bedding).

[2] Local officials including policemen and volunteer firemen cleared roads for relief supplies and transports.