Askja

Askja (Ice., 'basket'), the largest volcano in Iceland, rises out of the vast Odáthahraun lava-desert, near the centre of the island, in 65° N. lat. and 16° 45' W. long. Its vast crater is over 23 sq. m. in area, and about 17 miles in circumference. Almost circular in shape, it lies at a depth of over 700 feet within a mountain built up, by a distinctly marked series of lava-flows, round a volcanic vent, to a height of 4633 feet above the sea. Great volumes of steam are belched forth from numerous rifts and vents, and the whole surface is a chaos of rugged lava-floods, except in the SE., where there is a hot-water lake 5 miles in circumference, and a tract covered with pumice ejected in 1875. This great eruption first called general attention to Askja, and it has been stated that the volcano was only then formed; but the traces of innumerable earlier eruptions are found in the walls of the crater, already referred to, where the divisions are marked by the layers of red, slag-like lava, which time after time has formed the surface of the underlying lava-strata. Most of the lava in this eruption found an outlet, not from the crater, but some miles to the NE., where a bed, 20 miles long and 7 broad, now lies.