The impact of lava flows of 1706 in the city of Garachico. (Tenerife, Canary Islands, Spain)

One of the most significant eruption scenarios in the Canary Islands is that concerning the occurrence of effusive basaltic fissure eruptions in areas of volcanic rifts where there are low eruption rates. Eighty percent of historic volcanic activity produced in the Canary Islands has been located in these structures; and in 60% of the cases, the overspills occur in densely populated coastal areas, making them the most significant risk posed by volcanoes on the islands. The eruption of Garachico had the greatest socioeconomic impact of any historical phenomenon that ever occurred on Tenerife. Between 5 May and 13 June 1706, some 0.045 km(3) of volcanic materials were emitted, covering an area of 7.6 km(2). This paper focuses on the damage linked to the site of the overspills in the coastal area, as they were the cause of the greatest losses resulting from the eruption. This study also shows that the occurrence of effusive eruptions on rifts of this type not only requires us to look at the most likely eruption scenarios but also the geographic scenarios involved in the eruptions, as these determine the location patterns of the lava flows and the risks arising from them.