Uncapping subglacial eruption dynamics and glacier response

Volcanoes at high latitudes or at high elevations at temperate latitudes are commonly capped by glaciers.

Understanding the dynamics of volcano-ice interaction is important because meltwater production can influence eruption style and lead to sudden outburst floods or explosive lava-water interactions. In addition, glaciovolcanic deposits can be useful terrestrial indicators of past environments.

Glaciated volcanic systems are complex because meltwater availability and eruption style are dependent on a combination of magmatic, glacial and edifice characteristics. The relative influence of these characteristics are open fields of research.

SURGE aims to improve our understanding of glaciovolcanic interactions by studying ice-confined deposits at Katla volcano, Iceland.

Katla is a highly active and hazardous subglacial volcano from which all historic eruptions have occurred beneath an ice cap and have resulted in outburst floods.

While the Holocene eruptive record at Katla is well-known, the older parts of the edifice have received little attention.

A second aim of SURGE, therefore, is to improve our understanding of the pre-Holocene eruption history and edifice building at Katla.

New geological mapping will be carried out to determine the eruption and emplacement processes of pre-Holocene formations.

We will then use thermal modelling to determine the volume of ice that was melted during these eruptions in order to reconstruct the ancient glacier surface and extent.

Finally, radiometric dating of the formations will be used to build an age-constrained record of glacier dimensions and eruptive activity at Katla.

Our multidisciplinary approach will contribute to understanding of processes that occur beneath an ice cap or are too hazardous to observe. In addition, our estimates of ice volumes melted during these past eruptions will inform future hazard planning. The global prevalence of ice-capped volcanoes means that this study will have widespread relevance.