GNGTS 2017 - 36° Convegno Nazionale

260 GNGTS 2017 S essione 2.1 presence of very steep sidewalls. The “Polcevera” canyon, along with its parallel eastern “Bisa- gno” canyon, starts in front of the city of Genoa, only few kilometres offshore. The two canyons join south-westward in the so-called “Genova Canyon”, which is one of the largest submarine canyons in the entire Mediterranean sea. Besides the standard seismological analysis, we analysed the recordings of the three events following the method proposed by Manconi et al. (2016), who proposed a strategy to discrimi- nate earthquakes from landslides related signals, and in the latter case to obtain a preliminary characterization of the involved volumes. In summary, the adopted methodology, which was tested in the European Alps, discriminates between earthquakes and landslides mapping differ- ences between local magnitude (M L ) and duration magnitude (M D ). Indeed, the calibration of M L and M D relationships for earthquake monitoring within a specific geographic area is based on the constraint that the two values provide very similar (possibly the same) estimate of earth- quake magnitude. In the case of landslides, due to the relatively lower amplitude and longer duration of the generated signals, the ratio M L /M D is expected to be significantly less than 1. Furthermore, Manconi et al. (2016) calibrated also an empirical relationship between M D and the rockslide volume, which can be applied to estimate the volume involved in landslide phe- nomena. This work represents, to our knowledge, the first attempt of characterization of submarine landslide events from seismic signal analysis. It worth noting that the proposed seismic based strategy could complement with traditional approaches adopted for the monitoring the subma- rine gravitative phenomena (i.e., inspection by instruments on boats), with the advantage of be- ing easily implemented in real-time, and thus allowing to monitor the evolution of the off-shore topography, especially in unstable areas where the occurrence of multiple submarine landslides in short time intervals might be difficult to be performed with standard approaches. References Dammeier F., Moore J. R. , Haslinger F., Loew S.; 2011: Characterization of alpine rockslides using statistical analy- sis of seismic signals . J. Geophys. Res., 116, F04024, doi:10.1029/2011JF002037 Hibert C., Ekström G., Stark C. P.; 2014: Dynamics of the Bingham Canyon Mine landslides from seismic signal analysis. Geophys. Res. Lett., 41, 4535–4541, doi:10.1002/2014GL060592.Joint. Manconi A., Picozzi M., Coviello V., De Santis F., Elia L.; 2016: Real-time detection, location, and characterization of rockslides using broadband regional seismic networks . Geophys. Res. Lett., 43, doi:10.1002/2016GL069572 Spallarossa D., Ferretti G., Scafidi D., Turino C., Pasta M.; 2014: Performance of the RSNI-Picker . Seismological Research Letters 85 (6), 1.243–1.254; doi:10.1785/0220130136 Suriñach E., Vilajosana I., Khazaradze G., Biescas B., Furdada G., Vilaplana J. M.; 2005: Seismic detection and characterization of landslides and other mass movements . Nat. Hazards Earth Syst. Sci., 5, 791–798, doi:10.5194/ nhess-5-791-2005 Yamada M., Matsushi Y., Chigira M., Mori J.; 2012: Seismic recordings of landslides caused by Typhoon Talas (2011). Japan, Geophys. Res. Lett., 39, L13301, doi:10.1029/2012GL052174 Managing subjectivity AND elicitations in the TSUMAPS-NEAM project TSUMAPS-NEAM’s TI team, J. Selva 1 , A. Hoechner 2 , S.M. Iqbal 1 , S. Lorito 3 , H.K. Thio 4 1 Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy 2 Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany 3 Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy 4 AECOM, Los Angeles, California, USA The TSUMAPS-NEAMproject (http://www.tsumaps-neam.eu/; Basili et al. , 2017) produced the first region-wide long-term homogenous Probabilistic Tsunami HazardAssessment (PTHA) map from earthquake sources for the coastlines of the NE Atlantic, the Mediterranean, and