Publikationsdatum:
2017-04-04
Beschreibung:
A crucial point in the analysis of tectonic earthquakes occurring in a volcanic area is the inference of the
orientation of the structures along which the ruptures occur. These structures represent zones of weakness
which could favor the migration of melt toward the surface and the assessment of their geometry is a
fundamental step toward efficient evaluation of volcanic risk. We analyzed a high-quality dataset of 171 lowmagnitude,
tectonic earthquakes that occurred at Mt. Etna during the 2002–2003 eruption. We applied a
recently developed technique aimed at inferring the source parameters (source size, dip and strike fault) and
the intrinsic quality factor Qp of P waves from the inversion of rise times. The technique is based on
numerically calibrated relationships among the rise time of first P waves and the source parameters for a
circular crack rupturing at a constant velocity. For the most of the events the directivity source effect did not
allow us to constrain the fault plane orientation. For a subset of 45 events with well constrained focal
mechanisms we were able to constrain the “true” fault plane orientation. The level of resolution of the fault
planes was assessed through a non linear analysis based on the random deviates technique. The significance
of the retrieved fault plane solutions and the fit of the assumed source model to data were assessed through
a χ-square test. Most of the retrieved fault plane solutions agree with the geometrical trend of known
surface faults. The inferred source parameters and Qp are in agreement with the results of previous studies
Beschreibung:
Published
Beschreibung:
247-256
Beschreibung:
3.1. Fisica dei terremoti
Beschreibung:
JCR Journal
Beschreibung:
reserved
Schlagwort(e):
rise time
;
directivity
;
04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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