Naslov
Travertine and active faults: insights from the fissure ridge of Abano Terme (Padova)

Autori
Pola, Marco ; Zampieri, Dario ; Fabbri, Paolo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Physco-chemical process in seismic faults - Book of Abstracts / - , 2010, 55-56

Skup
Physico-chemical processes in seismic faults

Mjesto i datum
Padova, Italija, 18.11.2010. - 20.11.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
travertine mound ; fracture mesh ; dilational step-over ; thermal waters ; Euganean Geothermal Field

Sažetak
The Euganean Geothermal Field (EGF) develops along the north west-trending Schio- Vicenza fault system (SVFS), a structure that marks the western side of the Friuli and Veneto plain, which is the foreland of three surrounding chains: Dinarides, Alps and Apennines. Given the Neogene to Quaternary sinistrai strike-slip kinematics, superimposed on pre-existing normal faults, this structure is responsible for rock fracturing and permeability increase, enhancing the quick uprising of thermal waters. Until the sixties, one of the main natural occurrences of the outflow in the EGF was located in the town of Abano Terme, marked by a 5 meter-high hill of travertine, called Montirone. Thermal waters fed several pools located on the flat top and at the base of the ridge and were also channelized to move a mill-wheel. Exploitation of the thermal waters lowered the potenziometric level and dried up the hot springs. The hill is affected by a network of fractures mainly composed of two fracture sets (WNW-ESE and NNE-SSW), which allow us to refer to the travertine deposit as a fissure ridge. These structures have been studied in tectonically active regions of Turkey (Anatolia), Greece (Euboea island), USA (California) and Italy (Tuscany), showing typical features and providing significant information about stress orientation during travertine deposition. The analysis of the fracture network suggests that the fissure ridge is localized above a N120°E extensional fissure cutting the bedrock, which lies about one hundred meters beneath the alluvial cover. Preliminary data collected by traditional structural field techniques allow us to refer the fracture network to as a fault/fracture mesh of a dilational stepover between strike-slip or transtensional fault segments of the SVFS. Previous geostatistical analyses have revealed a prominent WNW-ESE transmissivity anisotropy in the bedrock, coinciding with the surficial tensional fissure deforming the travertine ridge. The presence of the Montirone travertine deposit strongly supports the existence of 1) a releasing structure in the subsurface which controls the development of the EGF and, 2) ongoing activity of the Schio-Vicenza fault, which places an urgent question about the seismic hazard of the area.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Rudarstvo, nafta i geološko inženjerstvo

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