PROBABILISTIC MAPPING OF GROUND DISPLACEMENT HAZARD

Abstract

The seismic hazard is most commonly described in terms of various parameters defining the intensity ground shaking. Other parameters like liquefaction potential, landslides, ground subsidence, tsunami etc. have been also used. However, permanent ground displacement due surface rupture along a fault is also an important parameter to be used for characterization of seismic hazard. This can cause tremendous damages, especially to lifeline structures such as highway bridges, tunnels, buried pipelines, etc. if they lie across a fault. This study emphasizes the need of estimation of ground displacement using the Probabilistic Seismic Hazard Analysis (PSHA) method. Various examples resulting in the damages due to permanent ground displacement followed by the earthquakes displaying vertical displacements. Necessary modifications in the commonly used PSHA approach have been described for its application to permanent ground displacement. Permanent ground displacement occurs only on the fault unlike other hazards which occur off the faults. The PSHA methodology is illustrated by the numerical results for the hypothetical faults. The additional probability of exceeding a specified value of permanent displacement for a given magnitude is described. The hazard curves is estimated for permanent ground displacement at different sites along its lengthfor different return periods. The study is implemented upon the real faults which is described in detail.