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Moment‐tensor inversion of LP events recorded on Etna in 2004 using constraints obtained from wave simulation tests
Author(s) -
Lokmer Ivan,
Bean Christopher J.,
Saccorotti Gilberto,
Patanè Domenico
Publication year - 2007
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 - 10.1029/2007gl031902
Subject(s) - moment tensor , inversion (geology) , waveform , geology , geodesy , seismology , source model , grid , geometry , deformation (meteorology) , physics , mathematics , computational physics , tectonics , quantum mechanics , voltage , oceanography
The persistent occurrence of long period (LP) events at Mt Etna became apparent with the installation of the first fixed broad‐band seismic network in late 2003. Repeating similar LP events from Nov. ‘03 to Sept. ‘04 indicate a non‐destructive source process. We perform moment tensor (MT) inversions on a stacked high S/N ratio representative LP signal, conducting a grid search for the source geometry and L2‐inversion for the source time function. Results indicate a NNW‐SSE oriented resonating sub‐vertical crack as the most probable source. This result is consistent with deformation and GPS observations. Crucial to this result are constraints imposed by detailed 3D full waveform numerical simulations in a heterogeneous tomographic model with topography, and in particular a detailed assessment of the influence of very near surface velocity structure on LP signals. Pulsating gas injection is hypothesised as the most likely LP trigger.