KATLA: PRESSURE OF CRYSTALLIZATION AND MAGMA CHAMBER DEPTH

The eruption of Grimsvotn in Iceland in May of 2011 put the scientific community on watch with regards to a possible eruption of Katla. Historically, a Grimsvotn eruption has preceded a Katla eruption, which is why studying the structure of the magma plumbing system beneath Katla’s caldera is vital for predicting eruptions and modeling the thermal structure of Iceland’s crust. There have been many past studies which sought to locate magma chambers beneath Katla using seismic and geodetic means, but petrologic data had not yet been analyzed. In this project, data files which contained chemical composition data for basaltic glasses from Katla were processed using computer programs. After filtering out anomalous data, a range of pressures was calculated which correlate to a magma chamber depth of approximately 20-25 km. The pressure data also confirms the presence of another chamber, located during seismic tests, which is found at a depth of 3 km. This chamber contains magma of a differing composition than the main magma chamber. Through further analysis of the data, the affects of water content were taken into consideration and resulted in a slight decrease in the pressure of crystallization values. Comparison of the results from Katla with other Icelandic volcanoes in the vicinity allows for the construction of a model for the structure of the crust in Iceland's Eastern Volcanic Zone. Further study of Iceland's volcanism could ultimately lead to more accurate eruption predictions and a better understanding of the tectonic processes which are at work on this portion of the Mid-Atlantic Ridge.