Publication Date:
2017-04-04
Description:
To understand the source complexity of the April 6, 2009 L’Aquila earthquake (MW =
6.3), a quick seismological analysis is done on the waveforms of the mainshock and
the larger aftershock that occurred on April 7, 2009. We prove that a simple waveform
analysis gives useful insights into the source complexity, as soon as the seismograms
are available after the earthquake occurrence, whereas the reconstruction of the
rupture dynamics through the application of sophisticated techniques requires a
definitely longer time. We analyzed the seismograms recorded at broadband and
strong motion stations and provided firm constraints on rupture kinematics, slip
distribution, and static surface deformation, also discriminating the actual fault plane.
We found that two distinct rupture patches associated with different fracture
propagation directions and possibly occurring on distinct rupture planes, characterized
the source kinematics of the April 6 events. An initial updip propagation successively
proceeds toward SE, possibly on a different plane. We also show that the same
processing, applied to the April 7, 2009 aftershock (MW = 5.6), allows us to obtain
useful information also in the case of lower magnitude events. Smaller events with
similar location and source mechanism as the mainshock, to be used as Green’s
empirical function, occur in the days before or within tens of minutes to a few hours
after the mainshock. These quick, preliminary analyses can provide useful constraints
for more refined studies, such as inversion of data for imaging the rupture evolution
and the slip distribution on the fault plane. We suggest implementing these analyses
for real, automatic or semi-automatic, investigations.
Description:
Published
Description:
389-406
Description:
1.1. TTC - Monitoraggio sismico del territorio nazionale
Description:
3.1. Fisica dei terremoti
Description:
JCR Journal
Description:
open
Keywords:
L'Aquila 2009 earthquake
;
directivity
;
seismic source
;
seismogram analysis
;
04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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