Non-double-couple earthquake mechanisms at the Hengill-Grensdalur volcanic complex, southwest Iceland

Geophysical Research Letters
By: , and 

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Abstract

The Hengill-Grensdalur area in Iceland generates frequent small non-double-couple earthquakes with explosive volumetric components. We collected high quality three-component digital recordings of 4,000 earthquakes on a purpose-designed, 32-station network in 1991, and determined focal mechanisms for 100 of the best-recorded earthquakes by inverting amplitude ratios. Many of the mechanisms are consistent, within the errors, with simultaneous shear and tensile faulting, with tensile faults parallel to the local spreading ridge, and shear faulting similar to that in the South Iceland transform-fault zone. Some events cannot be explained by this model, however, and require other processes, such as crack closing and partial compensation of tensile cracks by fluid flow.

Publication type Article
Publication Subtype Journal Article
Title Non-double-couple earthquake mechanisms at the Hengill-Grensdalur volcanic complex, southwest Iceland
Series title Geophysical Research Letters
DOI 10.1029/97GL00499
Volume 24
Issue 7
Year Published 1997
Language English
Publisher American Geophysical Union
Description 4 p.
First page 743
Last page 746
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