Time filter

Source Type

Caputo R.,University of Ferrara | Caputo R.,Research and Teaching Center for Earthquake Geology | Sboras S.,National Center for Environment and Sustainable Development | Pavlides S.,Research and Teaching Center for Earthquake Geology | And 3 more authors.
Earth-Science Reviews | Year: 2015

When compiling a database of active and capable faults, or more in general when collecting data for Seismic Hazard Assessment (SHA) purposes, the exploitation of the numerous and different sources of information represents a crucial issue. Also the understanding of their potential and limitations is essential. For example, using only information deriving from historically and/or instrumentally recorded earthquakes, as it has been commonly applied in the past, it is not sufficient and it could be, sometimes, even misleading in terms of SHA. In the present paper, the importance of using geological information for better defining the principal seismotectonic parameters of a seismogenic source is discussed and emphasized. In order to show this, four case studies of active faults recently reactivated by strong earthquakes have been selected from the Greek Database of Seismogenic Sources (GreDaSS). Each seismogenic source is analysed twice and separately for the two sources of information: firstly, on the basis of the single-event effects as mainly provided by historically or instrumentally recorded data, and secondly, on the basis of the cumulative effects consisting of any, mainly geological, evidence caused by multiple and repeated fault reactivations of the specific seismogenic source. The quality and accuracy of the produced results from both sources of information are then discussed in order to define the reliability of the outcomes and especially for calibrating the methodological approaches based on geological data, which have not only an intrinsically different degree of uncertainty and resolution, but also a greater potential in exploitability. As a matter of fact, an improved geological, in its broader sense, knowledge will help to fill in the gap of the geodetically and/or seismologically determined tectonic activity of hazardous regions. Moreover, including in a catalogue also the seismogenic sources that are not associated with historical and/or instrumental earthquakes will have a remarkable impact in future SHA analyses either probabilistic or deterministic ones. © 2015 Elsevier B.V. Source

Zuccarello A.R.,University of Catania | Caputo R.,University of Ferrara | Caputo R.,Research and Teaching Center for Earthquake Geology | Gueli A.M.,University of Catania | And 2 more authors.
Bollettino di Geofisica Teorica ed Applicata | Year: 2015

At Piano San Nicola site (Basilicata region, southern Italy) four samples of Glycimeris sp. shells were collected from the uppermost fossiliferous stratigraphic level of one of the main Quaternary marine terraces of the Taranto Gulf, which extends across the external sector of the southern Apennines fold-and-thrust belt, the Bradano Foredeep and the Apulian Foreland. These samples were analysed using the Electron Spin Resonance (ESR) technique, applied for the first time to this area. The obtained new chronological results provided reliable absolute ages ranging between 40.4 ±7.7 ka and 64.0 ±11.2 ka, which are in good agreement with the datings known in literature and obtained by different chronological methods as well as palaeontological inferences. The absolute ages achieved by our study represent fresh evidence supporting the chronological correlation between the marine terrace where Piano San Nicola site is located (Policoro Terrace) and the Marine Isotope Substage (MIS) 3.3. © 2015 - OGS. Source

Tarabusi G.,Italian National Institute of Geophysics and Volcanology | Tarabusi G.,University of Ferrara | Caputo R.,University of Ferrara | Caputo R.,Research and Teaching Center for Earthquake Geology
International Journal of Earth Sciences | Year: 2016

The Mirandola anticline represents a buried fault-propagation fold which has been growing during Quaternary due to the seismogenic activity of a blind segment belonging to the broader Ferrara Arc. The last reactivation occurred during the May 2012 Emilia sequence. In correspondence with this structure, the thickness of the marine and continental deposits of the Po Plain foredeep is particularly reduced. In order to better define the shallow geometry of this tectonic structure, and hence its recent activity, we investigated in a depth range which is intermediate between the surficial morphological observations and seismic profiles information. In particular, we carried out numerous passive seismic measurements (single-station microtremor) for obtaining the horizontal-to-vertical spectral ratio. The results of a combined analysis of the peak frequency and its amplitude nicely fit the available geological information, suggesting that this low-cost geophysical technique could be successfully applied in other sectors of wide morphologically flat alluvial plains to investigate blind and completely buried potential seismogenic structures. © 2016 Springer-Verlag Berlin Heidelberg Source

Caputo R.,University of Ferrara | Caputo R.,Research and Teaching Center for Earthquake Geology | Pellegrinelli A.,University of Ferrara | Bignami C.,Italian National Institute of Geophysics and Volcanology | And 4 more authors.
Geomorphology | Year: 2015

In May 2012, two moderate earthquakes (Mw=6.1 and 5.9), associated with a noticeable aftershock sequence affected the eastern sector of the Po Plain, northern Italy. The co-seismic areal uplift events are crucial for a better understanding of the seismotectonics of the broader area and thus for a better assessment of the seismic hazard in the region. In the present study, we compared the results of analyses based on high precision levelling, the DInSAR technique, the distribution of liquefaction occurrences, the geomorphological map of the area and the structural model of the region. The DInSAR technique revealed a marked uplift of the ground (up to 17cm), which was confirmed by high precision levelling. The results of both techniques substantially agreed, although there were some considerable local discrepancies, due to well-documented and diffuse liquefaction phenomena. Some strategic precautions when planning high-precision levelling networks are suggested. © 2015 Elsevier B.V. Source

Papathanassiou G.,Aristotle University of Thessaloniki | Mantovani A.,University of Ferrara | Tarabusi G.,University of Ferrara | Tarabusi G.,Italian National Institute of Geophysics and Volcanology | And 3 more authors.
Engineering Geology | Year: 2015

On the 20th and 29th of May 2012, two earthquakes occurred in Emilia-Romagna region (Northern Italy) triggering extensive liquefaction of the subsoil units. The consequences of liquefaction have been observed and reported by several agencies in a widespread area. The most impressive liquefaction manifestations were documented in a zone 3-4. km-long and 1. km-wide, where the villages of Sant'Agostino, San Carlo and Mirabello are located. The existing post-earthquake reports and the availability of geotechnical data provided by in-situ tests consist the basic ingredients for a computation of the liquefaction potential parameters within this zone. In particular, the Liquefaction Potential Index (LPI) and Liquefaction Severity Number (LSN) indexes were evaluated and then correlated by considering liquefaction phenomena either observed on site or not. Thus, the existing classifications of the LPI and LSN were evaluated and compared with the observed liquefaction-induced deformations. The latter was applied and validated for the first time within a liquefiable area using post-earthquake data, after the development by Tonkin and Taylor (2013). The outcome of this study shows that a threshold value of LPI around 13 or 14 is better to be taken into account instead of 5 for discriminating sites where liquefaction surface evidences should be expected from the 'non-liquefied' ones. Moreover, from the correlation of the LSN values with the cases of liquefaction-induced ground disruption it is concluded that the proposed threshold value of 10 fits statistically well with our dataset. In addition, a preliminary correlation of LPI and LSN indicates a trend that could be useful in future studies for delineating sites likely to liquefaction. © 2015 Elsevier B.V. Source

Discover hidden collaborations