Geotectonic aspects of the Beerenberg Volcano eruption 1970, Jan Mayen island

Abstract

The course of the Beerenberg Volcano eruption 1970 on Jan Mayen island is described. The eruption probably started with the opening of relatively short parallel (stopped) fissures, apparently tension gashes, in the NE part of the island, on the slope of the main stratovolcano. The opening of the fissures was probably due to lateral translation of a part of the island along a NNE-SSW directed tectonic Iine, the apparent surface projection of a deep-seated dextral strike-slip fault parallel to the Mid-Atlantic Ridge. The southern prolongation of this fault seems to have been the site of minor eruptions in 1732 and 1818, and of slight volcanic activity in 1971 subsequent to the major event in 1970. The opening of the gashes preceded the formation of parasitic craters which were active in producing basaltic lava and ash for a couple of weeks in 1970.