Katla volcano, located near the southern end of Iceland's eastern volcanic zone, is mostly hidden beneath the Myrdalsjökull icecap, which extends across the top of the photo. Valley glaciers descend from the summit icecap toward the coastal plain in this aerial view from the SSW. Explosive eruptions from Katla, among the largest tephra-producers in Iceland during historical time, have frequently been accompanied by damaging jökulhlaups, or glacier-outburst floods. Photo by Oddur Sigurdsson, 1985 (Icelandic National Energy Authority).