Inferring Aftershock Sequence Properties and Tectonic Structure Using Empirical Signal Detectors
Abstract
Seismotectonic studies of the 2008 Storfjorden aftershock sequence were limited to data acquired by the permanent, but sparse, regional seismic network in the Svalbard archipelago. Storfjorden's remote location and harsh polar environment inhibited deployment of temporary seismometers that would have improved observations of sequence events. The lack of good station coverage prevented the detection and computation of hypocenter locations of many low magnitude events (mb < 2.5) in the NORSAR analyst-reviewed bulletin. As a result, the fine structure of the sequence's space-time distribution was not captured. In this study, an autonomous event detection and clustering framework is employed to build a more complete catalog of Storfjorden events using data from the Spitsbergen (SPITS) array. The new catalog allows the spatiotemporal distribution of seismicity within the fjord to be studied in greater detail. Information regarding the location of active event clusters provides a means of inferring the tectonic structure within the fault zone. The distribution of active clusters and moment tensor solutions for the Storfjorden sequence suggests there are at least two different structures within the fjord: a NE-SW trending linear feature with oblique-normal to strike-slip faulting and E-W trending normal faults.
- Publication:
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Pure and Applied Geophysics
- Pub Date:
- February 2015
- DOI:
- 10.1007/s00024-014-0938-0
- Bibcode:
- 2015PApGe.172..359J
- Keywords:
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- Correlation detectors;
- Subspace detectors;
- Aftershock sequence;
- Tectonics;
- Seismicity