Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy

In this paper we present a review of the seismotectonic features (an analysis of earthquake focal mechanisms and the distribution of seismicity) of the Northern Apennines, Umbria Region (Italy) in the area between Sansepolcro and Norcia. For this analysis, we used Centroid Moment Tensor (CMT) data f...

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Main Authors: F. Frepoli, S. Pondrelli, M. G. Ciaccio
Format: Article
Language:English
Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 2006-06-01
Series:Annals of Geophysics
Subjects:
Online Access:http://www.annalsofgeophysics.eu/index.php/annals/article/view/3110
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author F. Frepoli
S. Pondrelli
M. G. Ciaccio
author_facet F. Frepoli
S. Pondrelli
M. G. Ciaccio
author_sort F. Frepoli
collection DOAJ
description In this paper we present a review of the seismotectonic features (an analysis of earthquake focal mechanisms and the distribution of seismicity) of the Northern Apennines, Umbria Region (Italy) in the area between Sansepolcro and Norcia. For this analysis, we used Centroid Moment Tensor (CMT) data for earthquakes with magnitude M>5.0 and data computed by implementing the standard CMT algorithm to compute Regional Centroid Moment Tensor (RCMT) estimates for moderate-magnitude earthquakes (4.5<M<5.5), integrating pre-existing datasets. We used first-motion polarities to obtain fault-plane solutions for small earthquakes (2.5<Md<4.5) recorded by the seismic network deployed by the Istituto Nazionale di Geofisica e Vulcanologia. We analyzed the main features of the seismicity and the present-day tectonic regime in order to relate the seismicity patterns to seismogenic structures beneath Central Italy. In particular, we discuss the important role of a major low-angle normal fault, the Altotiberina Fault, in controlling crustal seismicity in this region.
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spelling doaj.art-bd5ed23405bd48529076821fddd33f632022-12-22T02:44:02ZengIstituto Nazionale di Geofisica e Vulcanologia (INGV)Annals of Geophysics1593-52132037-416X2006-06-01494-510.4401/ag-3110Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, ItalyF. FrepoliS. PondrelliM. G. CiaccioIn this paper we present a review of the seismotectonic features (an analysis of earthquake focal mechanisms and the distribution of seismicity) of the Northern Apennines, Umbria Region (Italy) in the area between Sansepolcro and Norcia. For this analysis, we used Centroid Moment Tensor (CMT) data for earthquakes with magnitude M>5.0 and data computed by implementing the standard CMT algorithm to compute Regional Centroid Moment Tensor (RCMT) estimates for moderate-magnitude earthquakes (4.5<M<5.5), integrating pre-existing datasets. We used first-motion polarities to obtain fault-plane solutions for small earthquakes (2.5<Md<4.5) recorded by the seismic network deployed by the Istituto Nazionale di Geofisica e Vulcanologia. We analyzed the main features of the seismicity and the present-day tectonic regime in order to relate the seismicity patterns to seismogenic structures beneath Central Italy. In particular, we discuss the important role of a major low-angle normal fault, the Altotiberina Fault, in controlling crustal seismicity in this region.http://www.annalsofgeophysics.eu/index.php/annals/article/view/3110fault-plane solutionseismicityseismotectonicItaly
spellingShingle F. Frepoli
S. Pondrelli
M. G. Ciaccio
Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
Annals of Geophysics
fault-plane solution
seismicity
seismotectonic
Italy
title Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
title_full Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
title_fullStr Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
title_full_unstemmed Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
title_short Earthquake fault-plane solutions and patterns of seismicity within the Umbria Region, Italy
title_sort earthquake fault plane solutions and patterns of seismicity within the umbria region italy
topic fault-plane solution
seismicity
seismotectonic
Italy
url http://www.annalsofgeophysics.eu/index.php/annals/article/view/3110
work_keys_str_mv AT ffrepoli earthquakefaultplanesolutionsandpatternsofseismicitywithintheumbriaregionitaly
AT spondrelli earthquakefaultplanesolutionsandpatternsofseismicitywithintheumbriaregionitaly
AT mgciaccio earthquakefaultplanesolutionsandpatternsofseismicitywithintheumbriaregionitaly