Eruption forecast for Krafla Caldera



Since December 1975, Krafla, a volcano in northern Iceland, has been the site of repeated earthquakes, fissuring, and occasional eruptions (see cover figure). Intense monitoring of activity at Krafla has led to the recognition of a repetitive pattern of months-long inflation in the caldera area, followed by sudden deflation. The systematic tilting, fissuring, and eruptions are interpreted [Björnsson et al., 1977, 1979] as being due to the periodic filling of a central magma chamber under Krafla until a critical stress is reached, at which point magma is injected into rift zones extending as far as 60 km from the central volcano. As soon as a deflation episode and associated eruption cease, a new cycle resumes, with slow inflation as magma rises from a mantle source into the magma chamber.