Institutt for geovitenskap
Masterprosjekt: Klima - Energi - Ressurser - Geofarer

Magma chamber dynamics and deformation of the Grimsvötn volcano (Iceland)

This project was assigned to the Master's student Alette Kleven, who started her Master's program in Earth sciences, Geophysics, Autumn 2022.


Project description

Motivation (background):
Volcanic eruptions are intimately linked to many large scale Earth processes, such as subduction of tectonic plates and mantle plumes that start at the core-mantle boundary, traverse the lower and upper mantle and eventually reach the Earth’s surface. Moreover, volcanic eruptions can cause serious environmental damage and cause both short- and long-term climate change. An additional phenomenon linked to volcanic eruptions, which is especially valid for volcanoes covered by ice, such as Iceland, are the emission of large ash clouds into the atmosphere. Two of these ash clouds from Icelandic volcanoes (Eyjafjalljökull in 2010 and Grimsvötn in 2011) caused the cancellation of many thousands of flights. It is therefore important to study and understand volcanic eruptions.

Hypothesis (scientific problem):
Iceland is part of a hotspot, i.e. a location where a mantle plume reaches the surface, as well as part of the mid- Atlantic ridge. It is volcanically very active and consists of about 30 volcanic systems. The Grimsvötn volcano, which is part of the Eastern Volcanic Zone in Iceland, is one of the most active volcanoes of Iceland and erupts regularly. The most recent eruptions were in 1983, 1998, 2004 and 2011. In 2021, increased seismic activity suggested that an eruption was about to take place. However, this turned out not to be the case. Because of all this, Grimsvötn is a well monitored and studied area. In particular, seismicity, seismic tomography and deformation studies have been conducted at Grimsvötn. However, much work, especially connecting these various studies still remains to be done.
Previous work has shown that surface deformation can provide important clues on magmatic processes at depth. However, most models of surface deformation often use simplified geometries of the magma chamber. In addition, deformation is often modelled using elastic rather than visco-elastic models. We hypothesize that both the geometry of the magma chambers and the visco-elastic behavior are important for the interpretation of surface deformation Grimsvötn volcano.

Test (work):
At Grimsvötn, like in several other volcanoes, there seem to be two magma chambers: a lower and an upper crustal magma chamber. In this project, deformation due to the two magma chambers, will be studied by using the results from seismic tomography as well as seismicity. Most of the deformation is believed to be caused by the upper crustal magma chamber. However, the lower magma chamber, at times, also can play an important role. Possible coupling between the two magma chambers will therefore be taken into account by the deformation modeling. Finally, the deformation has mainly been studied using elastic, rather than visco-elastic models. The visco-elastic behavior of the area around the magma chambers, can probably not be ignored and will therefore be taken into account in the
modeling and deformation inversion.

Proposed course plan during the master's degree (60 ECTS):
GEOV355 (10 sp)
GEOV277 (10 sp)
GEOV300 (5 sp)
EU field course in Kiel (5 sp)
GEOV352 (5 sp)
GEOV325 (5 sp)
AG335 (10sp) (UNIS, Svalbard)
GEOV265 (10sp)