Selatangar is a long-abandoned fishing station situated in a sheltered inlet between two lava flows. The main road lies across quarried scoria craters (Moshólar) of the western flow. It was erupted about 2000 years ago from a 10 km long crater row which extends beyond Mt. Trölladyngja in the northeast. The eastern flow was erupted in the 12th century. West of Selatangar, the Moshólar lava flow met a temporary barrier, which impeded its progress, and a lake of pahoehoe lava accumulated behind it as a result. As the barrier gave way, the lava drained underground into the sea and the solidified crust subsided accordingly. The sunken lava lake, which is a few hundred metres across and irregular in shape, is surrounded by a 10-20 m high wall. Vertical scratches and lava coatings are seen and rare columns of former gas chimneys occur. The structure as a whole resembles Dimmuborgir at Mývatn. The main difference is the lack of scoria in the present case, which shows that the Selatangar structure was not of the rootless-crater type as is Dimmuborgir.
Kristján Sæmundsson, 2010