GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 3.1 89 and data processing, allow to obtain a depth migrated image with a good signal to noise ratio up to a depth of approximately 40 m, that is relevant for this type of investigation. An added value to these outcomes is that Patigno landslide represents a kind of destabilization phenomena commonly affecting the Apennine slopes, i.e. complex deep landslides, reactivated by surface movements that often are the most destructive. The combined use of both P-waves and SH-waves offers the possibility to obtain detailed insights of the whole landslide body, overcoming the limitation due to the low resolution of P- waves method for imaging shallow horizons and the low investigation depth of SH method. Both the seismic methodologies discussed in this work can be used to study large landslide and the choice of which to prefer mainly depends by the purpose of the work. If it is merely the individuation of the main deep slip surface at sufficient depth compared with the propagating wavelength, is preferable to use the P-wave reflection seismic method because it allows a quickly data acquisition, requires standard processing steps and devices. If the aim is instead the reconstruction of the internal architecture of the mass movements, the higher resolution of the SH-waves method offers greater guarantees of success. Taking into account the results obtained in this work it is possible to conclude that SH-wave seismic reflection methodology has revealed ��������� �������������� ���� ����� �� ���������� �� excellent potentialities that makes it applicable in contexts in which it is generally underestimated due to difficulty of acquisition, complexity of data processing and high costs. Notwithstanding these difficulties, ������� ������� ���������� SH-wave seismic reflection methodology provides many information about the shallow part of the subsurface and the union of these data with deeper P-wave seismic data gives a more robust description of the whole landslide body from the deepest discontinuity up to the very shallow portions of the landslide. In this regards, the complete knowledge of the landslide internal setting is fundamental to plan adequate and effective defence strategies. Acknowledgements. We gratefully acknowledge the support of Landmark/Halliburton for the use of the seismic software ProMAX and Prof. Mazzotti for his useful suggestion. Geophisical equipment was supplied by So.Ge.T. snc (www.sogetsnc.eu) and Geostudi Astier (www.geostudiastier.com ) which are gratefully acknowledged. References Apuani T., Arosio D., De Finis E., Stucchi E., Zanzi L. and Ribolini A.; 2012: Preliminary seismic survey on the unstable slope of Madesimo (Northern Italy). 25th Symposium on theApplication of Geophysics to Environmental and Engineering Problems (SAGEEP), Tucson, Arizona, USA, 452-459. Deidda G.P. and Balia R.; 2001: An ultrashallow SH-wave seismic reflection experiment on a subsurface ground model . Geophysics, 66 (4), 1097–1104. Guy D.E.; 2006: High-Resolution P- and S-wave Seismic Reflection Investigation of a Shallow Stratigraphic Sequence . Electronic Journal of Geotechnical Engineering, 11, 37 pp. Guy E.D., Nolen-Hoeksema R.C., Daniels J.J. and Lefchik T.; 2003: High-resolution SH-wave seismic reflection investigations near a coal mine-related roadway collapse feature . ������� �� ������� ����������� Journal of Applied Geophysics, 54 , 51 – 70. Federici P.R., Puccinelli A., Chelli A., D’Amato Avanzi G., Ribolini A. and Verani M.; 2000: La Grande Frana di Patigno di Zeri (Massa Carrar a). ������� ����� ��������� ����������� �� �������� Memorie della Accademia Lunigianese di Scienze, 70 , 3-51. Pugin A.J.M., Sargent S.L., Hunt L.; 2006: SH and P-wave seismic reflection using landstreamers to map shallow features and porosity characteristics in Illinois . Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP). Sheriff R.E., 2002; Encyclopedic Dictionary of Applied Geophysics . ������� �� ����������� �������������� ������ Society of Exploration Geophysicists, Tulsa, Oklahoma, U.S.A., 376 pp. Sheriff R.E. and Geldart L.P.; 1982 : Exploration Seismology : Vol. 1. History, Theory, and DataAcquisition. Cambridge Univ. Press., 628 pp. Stucchi E. and Mazzotti A.; 2009 : 2D seismic exploration of the Ancona landslide (Adriatic Coast, Italy). ���������� Geophysics 74 (5), B139. Stucchi E., Ribolini A. and Anfuso A.; 2014: High-resolution reflection seismic survey at the Patigno landslide, Northern Apennines, Italy. Near Surface Geophysics, 4 , 559-571 Yilmaz, O.; 2001: Seismic Data Analysis: Processing, Inversion, and Interpretation of Seismic Data . Society of Exploration Geophysicists, 2024 pp�.