Open AccessMoment tensors of microearthquakes from the Eyjafjallajökull volcano in South Iceland
Author(s) -
Dahm Torsten,
Brandsdóttir Bryndís
Publication year - 1997
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1997.tb00997.x
Subject(s) - geology , seismology , volcano , focal mechanism , magma , amplitude , earthquake swarm , magnitude (astronomy) , geophysics , geodesy , induced seismicity , physics , quantum mechanics , astronomy
SUMMARY Analyses of relative P ‐ and S ‐wave amplitudes of 15 selected earthquakes ( M L <2.3) from a seismic swarm, which occurred in May and June 1994 at the Eyjafjallajökull volcano in South Iceland, reveal similar radiation patterns, a thrust‐type double‐couple with an additional source component. All focal solutions have nearly vertical T ‐axes and horizontally oriented P ‐axes, with E‐W‐oriented nodal planes. The volume increase corresponding to an isotropic source component is estimated to be in the range of 24 m 3 . The temporal and spatial seismic pattern, small magnitude range, focal mechanisms and depth range of the Eyjafjallaökull earthquakes indicate vertical intrusion of magma into a confined region at the northern flank of the volcano.