Publication Date:
2022-06-10
Description:
This article has been accepted for publication in Geophysical Journal International ©: The Authors 2015. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
Description:
The Castrovillari scarps (Cfs) are located in northern Calabria (Italy) and consist of three main WSW-dipping fault scarps resulting from multiple rupture events. At the surface, these scarps
are defined by multiple breaks in slope. Despite its near-surface complexity, the faults likely
merge to form a single normal fault at about 200 m depth, which we refer to as the Castrovillari
fault. We present the results of a multidisciplinary and multiscale study at a selected site of
the Cfs with the aim to (i) characterize the geometry at the surface and at depth and (ii) obtain
constraints on the fault slip history. We investigate the site by merging data from quantitative
geomorphological analyses, electrical resistivity and ground penetrating radar surveys, and
palaeoseismological trenching along a ∼40 m high scarp. The closely spaced investigations
allow us to reconstruct the shallow stratigraphy, define the fault locations, and measure the
faulted stratigraphic offsets down to 20 m depth. Despite the varying resolutions, each of
the adopted approaches suggests the presence of sub-parallel fault planes below the scarps
at approximately the same location. The merged datasets permit the evaluation of the fault
array (along strike for 220 m within a 370-m-wide zone). The main fault zone consists of
two closely spaced NW–SE striking fault planes in the upper portion of the scarp slope and
another fault at the scarp foot. The 3-D image of the fault surfaces shows west to southwest
dipping planes with values between 70◦ and 80◦; the two closely spaced planes join at about
200 m below the surface. The 8-to-12-m-high upper fault, which shows the higher vertical
displacements, accommodated most of the deformation during the Holocene. Results from the
trenching analysis indicate a minimum slip per event of 0.6 m and a maximum short-term slip
rate of 0.6 mm yr–1 for the Cf. The shallow subsurface imaging techniques are particularly
helpful in evaluating the possible field uncertainties related to postfaulting modification by
erosional/depositional/human processes, such as within stream valleys and urbanized zones.
Description:
This study has benefited from funding provided by the Italian Presidenza
del Consiglio dei Ministri - Dipartimento della Protezione Civile
(DPC).
Description:
Published
Description:
1847–1863
Description:
6T. Studi di pericolosità sismica e da maremoto
Description:
JCR Journal
Keywords:
Image processing
;
Tomography
;
Geomorphology
;
Palaeoseismology
;
Fractures and faults
;
04.04. Geology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
