Deep‐seated downslope slip during strong seismic shaking

摘要: [1] Strong seismic waves cause frictional failure within regolith on hillslopes. The material responds anelastically to the combined oscillating dynamic and static gravitational stresses. Gravity drives preferential downslope movement of transiently weakened material. net effect over many earthquake cycles is a tens meter thick slow landslide, that sackung. classical approach hillside involves accelerations or equivalently shear tractions. Rate state friction quantifies starting coefficient few tenths higher apparent long-term from angle repose, 0.96–1.25 in calculations, retaining an extra digit. Furthermore, Coulomb stress ratio for lithostatic S-waves refracted toward vertical paths acceleration g's above scale depth 1/k, inverse wave number. In more detail, 0.13–0.35 g destabilizes slopes near repose. Seismologists expect such active major faults, compatible with widespread occurrence sackungen steep slopes. Accelerations = ∼1 destabilize shallow slopes, leading downhill movement, analogous object down vibrating ramp. However, are rare even absent California indicating rarity sustained 1 accelerations. A second mechanism may drive modest ∼19° as observed San Gabriel Mountains Andreas Fault. near-field velocity pulse strike-slip faults produces only but particle velocities m s−1 persisting >1 s. Dynamic stresses strains this extend all way free surface. criteria exceeded at depths. Failure greatly weakens allowing it move response gravity. This appears capable producing prehistoric per event slip Mountains.