Gravity model studies of the volcanic island Surtsey, Iceland
Þröstur Þorsteinsson*, and Magnús T. Guðmundsson#
Department of Physics, University of Iceland (now at Uni. of
Science Institute, University of Iceland
Abstract. Gravity data from Surtsey, collected by Cameron
et al., were reinterpreted in an effort to find a better model of the inner structure of Surtsey. The gravity field was calculated using 2 and a half dimensional calculations, where the measured field is simulated by gravity anomalies over polygons of finite extension. Existing knowledge of geology of Surtsey was used to guide model selection. Information about the eruption history, which is well know, were used and also information from a bore hole which was drilled in Surtsey 1979. Older models of Surtsey were also used as a guideline for modeling.
These information's were used as an input to the models we tried. We tried a few different models, some of which have previously been suggested and others are new. The model that fits the measured gravity field best doesn't suggest any pillow lava in the roots of Surtsey. On the other hand we have quite heavy sediments at the northern peninsula. Lava and lava fragments are at the southern beach, but the main part of Surtsey is made up of
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Figures: Profile of Surtsey in a 1:1 ratio,
the models (d is the "best"
model), profile with the structure of model
Surtsey in the news.