GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 3.1 577 Romagnoli, P., Arias, A., Barelli, A., Cei, M. and Casini, M.; 2010: An updated numerical model of the Larderello- Travale geothermal system, Italy. Geothermics, 39 ,292-313. Sen, M. K. and Stoffa, P. L.; 2013: Global Optimization Methods in Geophysical Inversion. Cambridge University Press, Cambridge, pp. 289. Santilano, A., Godio, A. and Manzella, A.; 2018: Particle swarm optimization for simultaneous analysis of magnetotelluric (MT) and time domain EM (TDEM) data. Geophysics, 83 (3):E151–E159. Siripunvaraporn, W.; 2012: Three-Dimensional Magnetotelluric Inversion: An Introductory Guide for Developers and Users. Surveys in Geophysics, 33 , 5-27. THE CONTRIBUTION OF GRAVITY MODELING IN SEISMOTECTONIC ANALYSIS: CASES HISTORY AND NEW AREAS OF INVESTIGATION V. Paoletti 1 , R. Nappi 2 , G. Gaudiosi 2 , P. Luiso 4 , F. Cella 3 , G. Florio 1 , M. Fedi 1 1 Department of Earth, Environment and Resources Science, University of Naples Federico II, Italy 2 Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Naples, Italy 3 Department of Biology, Ecology and Earth Sciences, University of Calabria, Italy 4 SOCOTECL Italia Srl, Lainate, Italy The aim of this paper is to identify and constrain the geometry (strike, dip direction and dip angle) of the seismogenic structures in areas of central-southern Apennines characterized by outcropping/ buried and/or active/silent faults. We use an integrated analysis of geo-structural, seismological and gravimetric data in GIS environment and focus on the identification and geometrical description of faults, with density contrast, both at the surface and at depth. At the surface, the gravity lineaments inferred by Multiscale Derivative Analysis (MDA, Fedi, 2002; Fedi et al. , 2005) were compared with the Quaternary structural setting mapped in the study areas and with the earthquakes’ epicentral distribution (Luiso et al. , 2018). The characterization of fault structures at depth was instead performed by the combination of the Depth from Extreme Points (DEXP, Fedi, 2007) gravity imaging method with hypocentral sections. Recently, we tested the effectiveness of our new multi-method approach to characterize seismogenic faults’ geometry in areas affected by different Quaternary tectonic environments: the Tyrrhenian margin of Apennines, the backbone of the Central Apennines chain and the Adriatic foredeep-foreland. The correlation between faults, earthquakes and MDA maxima allowed us to highlight four possible scenarios: 1) the existence of active faults, shown by a strong correlation among epicentral location of seismic clusters, faults and MDA lineaments; 2) the existence of buried active faults, highlighted by a correlation of MDA maxima with an associated spatial distribution of epicenters, but without correspondence with faults known from geological data; 3) the existence of inactive or silent faults, detected by the presence of faults reported in the geological datasets and literature which are correlated with a MDA maximum, but without correlation with earthquakes; 4) the existence of faults identified by literature but not correlated with MDA maxima; this could be due to faults putting in contact two lithologies with a similar density. This multi-method approach was already been applied for investigating (Fig. 1): - the neotectonic activity of the Campanian Plain and surrounding areas (Southern Italy) located in the inner portion of theAppennines chain and characterized by poor andmedium-