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Determining the seismic source mechanism and location for an explosive eruption with limited observational data: Augustine Volcano, Alaska
Author(s) -
Dawson Phillip B.,
Chouet Bernard A.,
Power John
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045977
Subject(s) - geology , seismology , volcano , dike , sill , broadband , seismometer , focal mechanism , induced seismicity , paleontology , petrology , political science , law
Waveform inversions of the very‐long‐period components of the seismic wavefield produced by an explosive eruption that occurred on 11 January, 2006 at Augustine Volcano, Alaska constrain the seismic source location to near sea level beneath the summit of the volcano. The calculated moment tensors indicate the presence of a volumetric source mechanism. Systematic reconstruction of the source mechanism shows the source consists of a sill intersected by either a sub‐vertical east‐west trending dike or a sub‐vertical pipe and a weak single force. The trend of the dike may be controlled by the east‐west trending Augustine‐Seldovia arch. The data from the network of broadband sensors is limited to fourteen seismic traces, and synthetic modeling confirms the ability of the network to recover the source mechanism. The synthetic modeling also provides a guide to the expected capability of a broadband network to resolve very‐long‐period source mechanisms, particularly when confronted with limited observational data.