Publication Date:
2017-10-19
Description:
In the last years the Apennines-Calabrian arc boundary has been affected by intense seismicity
concentrated in the Pollino mountain region. The Pollino is located at the northernmost edge of the
Calabrian Arc, the last remnant of subduction along the Africa- Eurasian boundary. The area is subject
to Northeast- Southwest extension, which results in a complex system of normal faults striking
Northwest-Southeast, nearly parallel to the Apenninic mountain range. The Italian Seismic Network
between 2010 and 2014 detected more than 5500 earthquakes in the area (Italian Seismological
Instrumental and Parametric Data- Base; http:// iside .rm .ingv .it). In 2010 and 2011 the earthquake
rate has been variable, with increasing and decreasing phases and maximum magnitudes below M=4.
On May 28th 2012, a shallow event with local magnitude of 4.3 struck, about 5 kilometers east of the
previous swarm. The seismic activity remained concentrated in the M=4.3 source region until early
August. At that time seismicity jumped back westward to the previous area, with several earthquakes
of magnitude larger than 3, culminating with a M=5.0 earthquake on 25 October 2012. The seismic
rate remained high for some months, but aftershock magnitudes did not exceed magnitude 3.7. The
seismic rate then suddenly decreased at the beginning of 2013 and stayed quite low for the rest of the
year up to the beginning of 2014. During these years several temporary seismic stations were
deployed in the area, improving the detecting threshold of the Italian Seismic Network and giving us
the opportunity to refine the location of the earthquakes hypocenters. A combined dataset, including
three-component seismic waveforms recorded by both permanent and temporary stations, has been
analyzed in order to obtain an appropriate 1-D and 3D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and,
relying on refined earthquakes location, we make inferences on the geometry of the fault system
responsible for the two strongest shocks. Swarm activity seems to occur on a diffuse crustal volume
more than on fault planes. To yield a better understanding of the origin of the ongoing seismic activity
in the Pollino area, using thousand of seismograms, we analyze vp and vp/vs models and anisotropic
parameters in the crust. The main goal of this study is to increase the understanding of the physical
mechanisms behind the seismic swarm and its influence on the seismic hazard of the Apennines-
Calabrian arc boundary region.
Description:
EAEE - ESC
Description:
Published
Description:
Istanbul - August 24-29 2014
Description:
2T. Tettonica attiva
Description:
open
Keywords:
SEISMIC SWARM
;
MAINSHOCK‐AFTERSHOCKS SEQUENCE
;
APENNINES‐CALABRIAN ARC BOUNDARY
;
REFINED EARTHQUAKES LOCATIONS
;
04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Poster session
Permalink