GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 3.1 591 Jiménez-Munt M., Fernàndez M., Vergés J., Afonso J. C., Garcia-Castellanos D. and J. Fullea; 2010: Lithospheric structure of the Gorringe Bank: Insights into its origin and tectonic evolution . Tectonics, 29, TC5019-1-TC5019- 16 Lo Iacono C., Gracia E., Zaniboni F., Pagnoni G., Tinti S., Bartolomé R., Masson D. G., Winn R. B., Lourenço N., Pinto de Abreu M., Danobeita J. J. and Zitellini N.; 2012: Large, deepwater slope failures: Implications for landslide-generated tsunamis . Geology, 40 , 931–934 Martìnez-Loriente, S., E. Gràcia, R. Bartolome, V. Sallarès, C. Connors, H. Perea, C. Lo Iacono, D. Klaeschen, P. Terrinha, J. J. Danobeitia, and N. Zitellini; (2013): Active deformation in old oceanic lithosphere and significance for earthquake hazard: Seismic imaging of the Coral Patch Ridge area and neighboring abyssal plains (SW Iberian Margin) . Geochem. Geophys. Geosyst., 14. Martinez-Loriente, S., Gràcia, E., Bartolomé, R., Sallarès, V., Dañobeitia, J.J. and Swim-06 Cruise Party; 2008: Pre- stack depth migration seismic imaging of the Coral 160 Patch Ridge and adjacent Horseshoe and Seine Abyssal Plains (Gulf of Cadiz): Tectonic implications. Trabajos de Geología, 30 , 49-54. Neves, M.C., Terrinha, P., Afilhado, A., Moulin, M., Matias, L., Rosas, F.; 2009: Response of a multi-domain continental margin to compression: study from seismic reflection– refraction and numerical modelling in the Tagus Abyssal Plain. Tectonophysics, 468 , 113–130. Roque C., Tectonostratigrafia do cenozóico das margens continentais sul e sudoeste portuguesas: um modelo de correlação sismostratigráfica phd thesis (2007) Ryan W.B.F., Hsü K. J., M. B. Cita M. B., Dumitrica P., Lort J., Maync W., Nesteroff W. D., Pautot G., Stradner H. and Wezel F. C.; 1973: Gorringe Bank—Site 120 . Initial Rep. Deep Sea Drill. Proj., 13 , 19–41 Sartori R., Torelli L., Zitellini N., Peis D., Lodolo E.; 1994: Eastern segment of the Azores–Gibraltar line (central– eastern Atlantic); an oceanic plate boundary with diffuse compressional deformation. Geology (Boulder), 22 (6), 555–558. Zitellini N., Gracia E., Matias L., Terrinha P., Abreu M.A., DeAlteriis G., Henriet J.P., Danobeitia J.J., Masson D.G., Mulder T., Ramella R., Somoza L., Diez S.; 2009: The quest for the Africa–Eurasia plate boundary west of the Strait of Gibraltar . Earth Planet. Sci. Lett., 280 , 13-50. Zitellini N., Ligi M., Matias L., Rovere M. and Shipboard Parties; 2002: VOLTAIRE 2002 Cruise Report . IGM, Technical Report nº 79, Bologna, Italy. Zitellini N., Mendes L. A., Córdoba D., Dañobeitia J., Nicolich R., Pellis G., Ribeiro A., Sartori R., Torelli L., Bartolomé R., Bortoluzzi G., Calafato A., Carrilho F., Casoni L., Chierici F., Corela C., Correggiari A., Della Vedova B., Gràcia E., Jornet P., Landuzzi M., Ligi M., Magagnoli A., Marozzi G., Matias L., Penitenti D., Rodriguez P., Rovere M., Terrinha P., Vigliotti L., Ruíz-Zahinos A.; 2001: Source of 1755 Lisbon earthquake and tsunami investigated. EOS , 28 , 290-291. GAS HYDRATE AND FREE GAS AMOUNTS ALONG CHILEAN MARGIN: OFFSHORE ITATA AND VALDIVIA I. de la Cruz Vargas-Cordero 1 , U. Tinivella 2 , L. Villar-Muñoz 3 , N. Foucher-Mc Coll 1 , N. Briones-Vargas 1 1 Universidad Andrés Bello, Viña del Mar, Chile 2 Istituto Nazionale di Oceanografía e di Geofísica Sperimentale - OGS, Trieste, Italy 3 GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany Introduction. Along the Chilean margin gas hydrates occurences are reported by detecting BSR reflector, in fact the BSR has been identified along the accretionary prism (Vargas- Cordero, 2009; Grevemeyer et al., 2003; Morales, 2003; Diaz-Naveas, 1999; Brown et al., 1996; Bangs and Brown, 1995). ODP Leg 141, drilling near the Chile triple junction, found average concentrations of 18% and 1% of volume of gas hydrate and free gas concentrations respectively (Bangs et al., 1993). Actually, in literature only few studies related to the hydrate quantification along the Chilean margin are available (Rodrigo et al., 2009; Vargas-Cordero et al., 2010; Vargas-Cordero et al., 2016). However, a regional estimate is needed in order to map the gas–phase distribution along this margin. In this context, an old seismic dataset was used to quantify the gas hydrate and free gas presence offshore Itata and Valdivia, Chile.