Seismic Slope Displacement Procedure for Interface and Intraslab Subduction Zone Earthquakes

Abstract

The seismic performance assessment of earth slopes and systems requires an estimate of the seismically-induced slope displacement (D). Modified Newmark-type analyses are useful to develop an estimate of D. Most simplified seismic slope displacement procedures were developed for shallow crustal earthquakes. In contrast, few procedures are available for subduction tectonic settings, which is especially the case for intraslab earthquakes. This study uses the comprehensive NGA-Sub ground motion database to formulate new seismic slope displacement models for subduction zone interface and intraslab earthquakes using a mixed random variable framework, which allows a straightforward implementation in engineering practice. The models are formulated in terms of the sliding mass properties (its yield coefficient and fundamental period), the spectral acceleration at the degraded period of the slope, and earthquake magnitude with peak ground velocity as an optional parameter. The models reveal that D scales differently for interface and intraslab earthquakes, which is contrary to what has been often assumed. The models also estimate displacement-compatible seismic coefficients for pseudostatic slope stability analyses. This study advances the performance-based seismic design of slope systems affected by subduction zone earthquakes.