Publication Date:
2017-04-04
Description:
Five large earthquakes shook southern Calabria in February–March 1783. We focused on the first shock (Me 6.9),
which occurred on 5 February in the Gioia Tauro Plain. Most investigators attribute the event to aW-dipping, highangle
fault running at the base of the Aspromonte crystalline bedrock on the ESE side of the Plain (Aspromonte
Fault). Other workers contend that the earthquake was generated by an E-dipping, low-angle blind fault (Gioia
Tauro Fault) similar to the adjacent Messina Straits Fault. In 1999–2000 we carried out four geochemical surveys in
the Gioia Tauro Plain with the aim of contributing to this debate with an independent line of evidence.We sampled
240 groundwater sites and measured a suite of in-situ physical and chemical parameters. Our goal was to gain
new insight into the seismogenic source by identifying geochemical anomalies associated with the deepening of
the hydrological circuits due to the presence of enhanced faulting/fracturing. The deep-fluid signatures are mainly
represented by temperature, salinity, total carbon and radon anomalies.We identified three zones of dominant deep
fluid discharge: the Nicotera-Galatro area (along the Nicotera-Galatro portion of theNW-trending Nicotera-Gioiosa
Jonica lineament), a small NW-SE trending area between Gioia Tauro and Seminara, and the coastline between
Rosarno and Palmi. This latter sector locates just above the upper edge of the hypothesised Gioia Tauro Fault. Most
of the geochemical anomalies are recorded around Rosarno, at the intersection between the Gioia Tauro Fault and
the Nicotera-Gioiosa Jonica lineament. In contrast, no evidence of groundwater deepening and active fracturing
was found along the Aspromonte Fault. Based on our new findings we updated the concepts of Geochemically Active
Fault Zone and Geochemical Interaction Fault Zone in view of the modern understanding of the hydro-mechanical
properties of fault zones and the faulting mechanisms promoting fracture permeability in the crust.
Description:
Published
Description:
363–380
Description:
3.2. Tettonica attiva
Description:
JCR Journal
Description:
reserved
Keywords:
5 February 1783 earthquake, Italy, Calabria, fault zones, fluid geochemistry, Gioia Tauro Plain, recent tectonics
;
04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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