Publication Date:
2022-04-29
Description:
We carried out new geological, morphotectonic, geophysical and paleoseismological investigations on the
Meduno Thrust that belongs to the Pliocene-Quaternary front of the eastern Southern Alps in Friuli (NE Italy).
The study area is located in the Carnic Prealps, where a series of alluvial terraces, linked to both climatic and
tectonic pulses characterises the lower reach of the Meduna Valley. In correspondence of the oblique ramp of the
Meduno Thrust, the Late Pleistocene Rivalunga terrace shows a set of scarps perpendicular to the Meduno valley,
often modified by human activity. In order to reconstruct the tectonic setting of the area and identify the location
for digging paleoseismological trenches, integrated geophysical investigations including electrical resistivity
tomography, seismic refraction and reflection, ground penetrating radar and surface wave analyses (HVSR, ReMi
and MASW), were carried out across the scarps of the Rivalunga terrace. Geophysical surveys pinpointed that in
correspondence of the oblique ramp, stress is accommodated by a transpressive thrust system involving all the
seismo-stratigraphic horizons apart from the ploughed soil. Trenching illustrated the Meduno Thrust movements
during Late Pleistocene-Holocene. Trenches exhibited both shear planes and extrados fracturing, showing
deformed alluvial and colluvial units. 14C datings of the colluvial units show that the most recent fault movements
occurred after 1360 CE and 1670 CE. The age of the deformed stratigraphic units compared with the
earthquakes listed in current catalogues, suggests that the 1776 earthquake (Mw 5.8, Io = 8–9 MCS) could
represent the last seismic event linked to the Meduno thrust activity. This study provided new quantitative
constraints improving seismic hazard assessment for Carnic prealpine area.
Description:
The research developed in the framework of the agreement between
the Regione Autonoma Friuli Venezia Giulia - Direzione Centrale
Ambiente ed Energia - Servizio Geologico, the Istituto Superiore per la
Protezione e la Ricerca Ambientale (I.S.P.R.A.) and the University of
Udine. The project was funded by the Regione Autonoma Friuli Venezia
Giulia, Direzione Centrale Ambiente ed Energia, Servizio Geologico (C.I.
G.: Z0E0C5EF75, p.i. Maria Eliana Poli).
Description:
Published
Description:
229071
Description:
2T. Deformazione crostale attiva
Description:
JCR Journal
Keywords:
Active fault
;
Paleoseismology
;
Morphogenic earthquake
;
Eastern Southern Alps
;
Applied geophysics
;
NE Italy
;
04.04. Geology
;
04.07. Tectonophysics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
