The little brother of Surtsey. Jólnir was a volcanic islet, created west of Surtsey in early July of 1966 by a secondary vent of the same eruption that brought the larger island out of the waves (albeit three years later). Unfortunately it was less stable than Surtsey, composed mostly of crumbly pumice-type rock (hyaloclastite) due to the largely underwater nature of the eruption. For some months the creative volcano strove against the destruction of the waves; by late September nothing was left but a but a ridge or promontory which high tide covered. At some point in October, the ocean had done its work and the last stones of Jólnir crumbled under the sea. It is now a shoal off the coast of its more resilient sibling, a seamount reaching, at shallowest point, 39 meters' depth.
»Jólnir« means »Yule-er«, in sense approximately »Yulemaker«, »the one who celebrates Yule«, or the one for whom it is celebrated. It is another name for Odin.