Geophysical Characterization of the Salna Sinking Zone, Garhwal Himalaya, India

摘要: Infrastructure and communication facilities are repeatedly affected by ground deformation in Gharwal Himalaya, India; for effective remediation measures, a thorough understanding of the real reasons these movements is needed. In this regard, we undertook an integrated geophysical geotechnical study Salna sinking zone close to Main Central Thrust Garhwal Himalaya. Our data include eight combined electrical resistivity tomography (ERT) induced polarization imaging (IPI) profiles spanning 144–600 m, with 3–10 m electrode separation Wenner–Schlumberger configuration, five micro-gravity 10–30 station spacing covering region. The ERT sections clearly outline heterogeneity subsurface lithology. Further, ERT, IPI, shaliness (shaleyness) infer absence clayey horizons slip surfaces at depth. However, Bouguer gravity analysis has revealed existence several faults subsurface, much beyond reach majority sections. These inferred vertical subvertical run parallel existing major lineaments tectonic elements crisscross network divided entire region into blocks subsurface. studies stress that village area presently taking place along faults. Chamoli earthquake March 1999 probably triggered seismically few gravity-inferred shallow may hint blind faults, which could serve as future source(s) geohazards Soil samples two sites were studied laboratory. These, stability four slope sections, have indicated critical state Thus, our emphasize crucial role finding fine structure deeper depth level; supported IPI intervals, they can satisfactorily explain Lesser also lend support findings. yielded better mass-wasting mechanism