Closing crack earthquakes within the Krafla caldera, North Iceland
Moment tensor analysis with a Bayesian approach was used to analyse a non-double-couple (non-DC) earthquake (Mw ∼ 1) with a high isotropic (implosive) component within the Krafla caldera, Iceland. We deduce that the earthquake was generated by a closing crack at depth. The event is well located, wit...
Published in: | Geophysical Journal International |
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Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Royal Astronomical Society
2016
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Subjects: | |
Online Access: | http://eprints.esc.cam.ac.uk/3668/ http://eprints.esc.cam.ac.uk/3668/1/Geophys.%20J.%20Int.-2016-Mildon-1137-41.pdf http://eprints.esc.cam.ac.uk/3668/2/suppl_data.zip http://gji.oxfordjournals.org/content/207/2/1137 https://doi.org/10.1093/gji/ggw325 |
Summary: | Moment tensor analysis with a Bayesian approach was used to analyse a non-double-couple (non-DC) earthquake (Mw ∼ 1) with a high isotropic (implosive) component within the Krafla caldera, Iceland. We deduce that the earthquake was generated by a closing crack at depth. The event is well located, with high signal-to-noise ratio and shows dilatational P-wave first arrivals at all stations where the first arrival can be picked with confidence. Coverage of the focal sphere is comprehensive and the source mechanism stable across the full range of uncertainties. The non-DC event lies within a cluster of microseismic activity including many DC events. Hence, we conclude that it is a true non-DC closing crack earthquake as a result of geothermal utilization and observed magma chamber deflation in the region at present. |
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