KatlaArticle Free Pass Katla, subglacial volcano, southern
Iceland, located underneath Mýrdalsjökull (Mýrdals Glacier).
Katla’s summit sits at 4,961 feet (1,512 metres) above sea
level, and its oval caldera is about 6 miles (10 km) across at
its widest. Katla is one of Iceland’s most active volcanoes,
having erupted at least 20 times since the year 1100. Some of
these eruptions have been preceded by or occurred simultaneously
with eruptions of Eyjafjallajökull volcano, located some 15.5
miles (25 km) to the west. Katla produces basaltic magmas that
typically do not cause explosive eruptions. (Basaltic magmas are
low in viscosity and contain low concentrations of gases.)
However, when rising magma makes contact with the overlying
glacier ice, the ice is vaporized. The resulting buildup of gas
pressure beneath the glacier may produce an explosive eruption
of steam and ash. Katla’s eruption in 1918 was characterized by
explosive activity that produced voluminous ash clouds and
landslides. In addition, the tremen