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http://hdl.handle.net/2122/6281
Authors: | Improta, L.* Ferranti, L.* De Martini, P. M.* Piscitelli, S.* Bruno, P. P.* Burrato, P.* Civico, R.* Giocoli, A.* Iorio, M.* D'Addezio, G.* Maschio, L.* |
Title: | Detecting young, slow‐slipping active faults by geologic and multidisciplinary high‐resolution geophysical investigations: A case study from the Apennine seismic belt, Italy. | Journal: | Journal of Geophysical Research | Series/Report no.: | /115 (2010) | Publisher: | American Geophysical Union | Issue Date: | 9-Nov-2010 | DOI: | 10.1029/2010JB000871 | URL: | http://www.agu.org/pubs/crossref/2010/2010JB000871.shtml | Keywords: | active fault integrated geophysical investigations morpho-tectonic analysis paleoseismology Val d'Agri Southern Italy 1857 Earthquake |
Subject Classification: | 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology 04. Solid Earth::04.04. Geology::04.04.09. Structural geology 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques |
Abstract: | The Southern Apennines range of Italy presents significant challenges for active fault detection due to the complex structural setting inherited from previous contractional tectonics, coupled to very recent (Middle Pleistocene) onset and slow slip rates of active normal faults. As shown by the Irpinia Fault, source of a M6.9 earthquake in 1980, major faults might have small cumulative deformation and subtle geomorphic expression. A multidisciplinary study including morphological-tectonic, paleoseismological, and geophysical investigations has been carried out across the extensional Monte Aquila Fault, a poorly known structure that, similarly to the Irpinia Fault, runs across a ridge and is weakly expressed at the surface by small scarps/warps. The joint application of shallow reflection profiling, seismic and electrical resistivity tomography, and physical logging of cored sediments has proved crucial for proper fault detection because performance of each technique was markedly different and very dependent on local geologic conditions. Geophysical data clearly (1) image a fault zone beneath suspected warps, (2) constrain the cumulative vertical slip to only 25–30 m, (3) delineate colluvial packages suggesting coseismic surface faulting episodes. Paleoseismological investigations document at least three deformation events during the very Late Pleistocene (<20 ka) and Holocene. The clue to surface-rupturing episodes, together with the fault dimension inferred by geological mapping and microseismicity distribution, suggest a seismogenic potential of M6.3. Our study provides the second documentation of a major active fault in southern Italy that, as the Irpinia Fault, does not bound a large intermontane basin, but it is nested within the mountain range, weakly modifying the landscape. This demonstrates that standard geomorphological approaches are insufficient to define a proper framework of active faults in this region. More in general, our applications have wide methodological implications for shallow imaging in complex terrains because they clearly illustrate the benefits of combining electrical resistivity and seismic techniques. The proposed multidisciplinary methodology can be effective in regions characterized by young and/or slow slipping active faults. |
Appears in Collections: | Article published / in press |
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File | Description | Size | Format | Existing users please Login |
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Improta_etal_2010_JGR-VdA.pdf | published manuscript | 15.03 MB | Adobe PDF | |
paper_2010JB000871_R2_merged.pdf | accepted manuscript | 3.23 MB | Adobe PDF | View/Open |
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