Boiero D.,Polytechnic University of Turin |
Boiero D.,WesternGeco |
Socco L.V.,Polytechnic University of Turin |
Stocco S.,Gamut S.r.l |
Wisen R.,Danmark A/S
Leading Edge | Year: 2013
Rayleigh-wave analysis is nowadays a standard tool for retrieving near-surface S-wave velocity models. The method, usually based on the inversion of surface-wave dispersion curves adopting a 1D forward operator, is most often applied to laterally varying sites and often on long and continuous seismic lines. The processing is performed using one of many available wavefield-transform techniques and results in several local dispersion curves estimated along the survey line. The dispersion curves are inverted to provide local S-wave velocity models which are merged to reconstruct 2D/3D structures. © 2013 © 2013 by The Society of Exploration Geophysicists.
Wisen R.,Ramboll |
Boiero D.,Gamut s.r.l. |
Maraschini M.,Polytechnic University of Turin |
Socco L.V.,Polytechnic University of Turin
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010
Shear wave velocity models can be built through surface wave analysis. For the presented field case, preliminary data analysis has evidenced the possibility of retrieving several modes of vibration of Rayleigh waves and This suggest the use of a multimodal inversion algorithm to estimate a pseudo-3D shear wave velocity model. The full analysis has been performed starting from a preliminary Monte Carlo inversion applied on the representative dispersion curves. After the Monte Carlo inversion, which provides a consistent 1D reference model for each line, the dispersion curves have been inverted simultaneously adopting a linearised laterally constrained inversion (LCI) to obtain a pseudo-3D shear wave velocity model. © 2010, European Association of Geoscientists and Engineers.
Stocco S.,Gamut Srl |
Bena E.,Gamut Srl |
Ansaldi G.,University of Turin
Geoingegneria Ambientale e Mineraria | Year: 2016
We carried out a geophysical survey in the town of Chiusa di Pesio (CN) for the stratigraphic characterization and the large scale evaluation of the Vs30 parameter. The survey was carried out in urban areas, on roads affected by traffic. Because of the logistic problem given by the urban environment, and the need to calculate the Vs30 parameter and to identify possible velocity inversion, we used the surface waves method (SWM) with a land seismic streamer, trailed by a vehicle. The survey technique consists in the acquisition and processing of numerous vertical profiles of velocity of propagation of shear waves (S). The SWM data processing consists of the simultaneous inversion with SCI technique (Spatially Constrained Inversion) that constrains all Vs profiles and returns a pseudo-3D model, not interpolated, of the velocity of propagation of the S waves. The results show that the town is divided into two main areas: the western part, placed at higher level because of a terrace, shows S wave velocity inversion, caused by the presence of rigid layers overlying softer layers (river-torrential terraced with different grain size) and does not identify the bedrock up to the investigated depth; the eastern part, depressed, generally shows a vertical gradient of propagation velocity of S waves and identifies the seismic bedrock. The Vs30 parameter mapping shows an increase in the value of the parameter in the most urbanized area, close to the hills. In the northern part of the area, in the plain, there was a decrease of the parameter values caused by the presence of a thicker overburden of river-torrential deposits, characterized by a low velocity of propagation of the S waves and by the deepening of the bedrock. The survey shows that the surveyed areas are stable and susceptible to seismic amplification.
Boiero D.,Gamut S.r.l |
Calzoni C.,Gamut S.r.l |
Socco L.V.,Polytechnic University of Turin
73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 | Year: 2011
We present here a joint inversion method to build P- and S-wave velocity models from surface-wave and P-wave refraction data, specifically designed to deal with laterally varying layered environments which can present strong velocity contrasts with depth. In this case, a smooth minimum-structure inversion produces smooth models even for geological models, which are overall layered. The proposed algorithm is also able to incorporate a-priori information available over the site and any physical law to link model parameters. This method presents advantages with respect to individual surface wave analysis and refraction tomography since it imposes internal consistency for all the model parameters, reducing the required a-priori assumptions and the ill-ness of the two methods. We describe the algorithm and we show its application to synthetic and field datasets.
Piga C.,University of Cagliari |
Piroddi L.,University of Cagliari |
Pompianu E.,University of Sassari |
Ranieri G.,University of Cagliari |
And 2 more authors.
Remote Sensing | Year: 2014
In this paper, the authors present a recent integrated survey carried out on an archaeological urban site, generally free of buildings, except some temporary structures related to excavated areas where multi-chamber tombs were found. The two methods used to investigate this site were thermal infrared and ground penetrating radar (GPR). The thermography was carried out with the sensor mounted under a helium balloon simultaneously with a photographic camera. In order to have a synthetic view of the surface thermal behavior, a simplified version of the existing night thermal gradient algorithm was applied. By this approach, we have a wide extension of thermal maps due to the balloon oscillation, because we are able to compute the maps despite collecting few acquisition samples. By the integration of GPR and the thermal imaging, we can evaluate the depth of the thermal influence of possible archaeological targets, such as buried Punic tombs or walls belonging to the succeeding medieval buildings, which have been subsequently destroyed. The thermal anomalies present correspondences to the radar time slices obtained from 30 to 50 cm. OPEN ACCESS Furthermore, by superimposing historical aerial pictures on the GPR and thermal imaging data, we can identify these anomalies as the foundations of the destroyed buildings. © 2014 by the authors.
Stocco S.,Gamut S.r.l. |
Castiglia C.,Golder Associates |
Mainero D.,Acea Ambiente
Coupled Phenomena in Environmental Geotechnics: From Theoretical and Experimental Research to Practical Applications - Proceedings of the International Symposium, ISSMGE TC 215 | Year: 2013
Acea Pinerolese Industriale (Acea) has presented a change to the final closure design of the "Torrione 4" MSW landfill in order to be able to fill the additional volume freed by waste settlements developed during construction. Since Torrione 4 landfill is a "piggybacking" expansion of a previous landfill, separated by a clay liner, Acea has been requestedto estimate the settlements inducedonthe clay liner by the waste deposition and thus be able to evaluate the total occupied volume. As non-invasive methods were needed, seismic investigation based on SWM (Surface Waves Method) has been carried out in order to confirm analytical predictions of the settlements at liner level, calculated using common design approaches such as Sowers (1973). This methodology has allowed the contact between the expansion and the previous landfill to be identified, confirming the analytical predictions. © 2013 Taylor & Francis Group.