Closing crack earthquakes within the Krafla caldera, North Iceland

Zoë K. Mildon; David J. Pugh; Jon Tarasewicz; Robert S. White; Bryndís Brandsdóttir

doi:10.1093/gji/ggw325

Closing crack earthquakes within the Krafla caldera, North Iceland

Zoë K. Mildon^*, David J. Pugh, Jon Tarasewicz, Robert S. White, Bryndís Brandsdóttir

^*Corresponding author for this work

Science Institute

Research output: Contribution to journal › Letter › peer-review

6 Citations (Scopus)

Abstract

Moment tensor analysis with a Bayesian approach was used to analyse a non-double-couple (non-DC) earthquake (M_w ~ 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.

Original language	English
Article number	ggw325
Pages (from-to)	1137-1141
Number of pages	5
Journal	Geophysical Journal International
Volume	207
Issue number	2
DOIs	https://doi.org/10.1093/gji/ggw325
Publication status	Published - 1 Nov 2016

Bibliographical note

Publisher Copyright:
© The Authors 2016. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Other keywords

Earthquake source observations
Hydrothermal systems
Volcano seismology

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10.1093/gji/ggw325

Cite this

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title = "Closing crack earthquakes within the Krafla caldera, North Iceland",

abstract = "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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doi = "10.1093/gji/ggw325",

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AU - Mildon, Zoë K.

AU - Pugh, David J.

AU - Tarasewicz, Jon

AU - White, Robert S.

AU - Brandsdóttir, Bryndís

N1 - Publisher Copyright: © The Authors 2016. Published by Oxford University Press on behalf of The Royal Astronomical Society.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - 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.

AB - 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.

KW - Earthquake source observations

KW - Hydrothermal systems

KW - Volcano seismology

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Closing crack earthquakes within the Krafla caldera, North Iceland

Abstract

Bibliographical note

Other keywords

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