Publication Date:
2017-04-04
Description:
The area investigated, the Sansepolcro basin, is characterized by the
presence of important earthquakes in the past with estimated intensity
even larger than IX MCS (the 1352 Monterchi earthquake, the 1389
Boccaserriola, the 1458 Citta’ di Castello, the 1781 Cagliese and the
1917 Monterchi-Citerna earthquakes, CPTI Working Group, 2004) and
by a surprisingly scarce instrumental seismicity compared to the
adjacent areas struck by high seismicity (Castello et al., 2005; Ciaccio
et al., 2006). The area north of Sansepolcro has been struck in recent
years by four minor sequences, occurred between 1987 and 2001 with
magnitude ranging from Ml3.0 to Mw4.7. In this work we analyse the
most important earthquakes of the 20th century occurred in the
Altotiberina Valley in 1917, 1918, 1919 and 1948; in particular
instrumental relocation, focal mechanisms and Ms and Mw magnitude
estimation are re-evaluated. The relocation of these earthquakes is
particularly critical and is an important issue. An instrumental and
precise location is critical for the complexity of the problems associated
with the study of seismograms prior to the first half of the twentieth
century and is relevant because in the surrounding regions higher
seismicity is observed. Regarding this peculiarity of the area, it’s very
important to detect the location of the historical earthquakes: in particular,
the 1917 event is often associated to the possibility that the
regional low angle Altotiberina Fault (Barchi et al., 1998) is able or not
to nucleate large- or moderate-magnitude events, being historically
located close to its surface (Boncio and Lavecchia, 2000).
Description:
Unpublished
Description:
Vienna
Description:
3.1. Fisica dei terremoti
Description:
open
Keywords:
Sansepolcro Basin
;
Historical seismicity
;
04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Poster session
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