FIGURE 1. Map of the northwest part of Vatnajökull showing the location of the 1996 eruptive fissure (solid line, in box), midway between the s.

From the following article:

Ice–volcano interaction of the 1996 Gjálp subglacial eruption, Vatnajökull, Iceland

Magnú T. Gudmundsson, Freysteinn Sigmundsson and Helgi Björnsson

Nature 389, 954-957(30 October 1997)



ubglacial calderas of the Bárdarbunga and Grímsvötn volcanoes22, 26. The contours show ice surface topography (in metres). The eruptive site is well known from accurate mapping and radio-echo soundings that have revealed the bedrock topography22. The Bárdarbunga and Grímsvötn volcanoes are among the most active in Iceland with frequent eruptions and associated jökulhlaups documented in the historical record. A subglacial lake is sustained by geothermal activity within the Grímsvötn caldera22, 27. Jökulhlaups originate from the lake, usually at intervals of a few years, but eruptions may disrupt the periodicity of the jökulhlaups22, 23, 28. The most recent eruptions in the Grímsvötn area occurred in 1934, 1938, 1983 and 1984 (ref. 23). The crosses in the southeast corner of Bárdarbunga are small ice cauldrons considered formed by a minor subglacial eruption at the same time as the main eruption. The locations of the maps and sections in Fig. 2 are shown. Inset shows ice caps and the volcanic zones of Iceland.