1980 Azores Islands earthquake

Background In 1950, another strong earthquake had rocked the Azores Islands region, and this was the largest earthquake since. Description 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. The 1980 earthquake was the result of movement along a northwest to southeast trending strike-slip fault. Because of this research, information now points towards Azores volcanism being controlled by earthquake movement. == Damage and casualties ==

The earthquake that struck the Azorean islands was 6.9 . It caused considerable damage on three separate islands (Terceira, São Jorge Island, and Graciosa), destroying several buildings. 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. Additionally, the injuries were set at 300, but this was also revised to more than 400. Minor damage was recorded at Pico and Faial islands. No fatalities were recorded at the Lajes Field air base, nor any major damage. == Relief efforts and response ==

United States Navy and Air Force personnel stationed at Lajes functioned as disaster relief workers, Portuguese Air Force members brought supplies to earthquake victims, while a Portuguese Navy transported medical officials to the island. The Portuguese president, António Ramalho Eanes, flew in on a plane accompanied by medical personnel and supplies (such as bedding). Local officials including policemen and volunteer firemen cleared roads for relief supplies and transports. Responding to the situation, these officials were also involved in looking for survivors in the rubble. Soon after, tents were erected to replace the destroyed or unsafe homes for approximately 200 families of the islands. Portable homes were constructed by the People to People International project fund, resulting in 100 shelters. Three days of national mourning were declared by Eanes. Following the relief efforts, 19 seismographic stations were installed to monitor seismic activities. Eleven of these were used to monitor earthquake activity, while the other eight also record information on the island's geothermal areas. The earthquake forced hundreds of people to leave the country for the United States. It occurred during a period of several major natural disasters in which many residents of the island left; in 1975, 8,000 residents left. In 1981, however, just 2,500 people left the island. == Analysis and current situation ==

Later studies of the events leading up to the tragedy found several factors contributing to the extent of the damage. A. Malheiro (2006) linked five major causes to damage from these earthquakes. The buildings most damaged by the earthquake were near fault lines on top of loosely packed soil. They tended to be of poor construction and did not conform to proper building code, nor had they been adequately examined. The area around the Azores remains active. Threats from earthquakes and landslides remain. ==See also==