Geologic and geomorphic controls on rockfall hazard: how well do past rockfalls predict future distributions?

Abstract

To evaluate the geospatial hazard relationships between recent (contemporary) rockfalls and their prehistoric predecessors, we compare the locations, physical characteristics, and lithologies of rockfall boulders deposited during the 2010-2011 Canterbury earthquake sequence (CES) (n D 185) with those deposited prior to the CES (n = 1093). Population ratios of pre-CES to CES boulders at two study sites vary spatially from ∼ 5 V 1 to 8.5 V 1. This is interpreted to reflect (i) variations in CES rockfall flux due to intra-A nd inter-event spatial differences in ground motions (e.g., directionality) and associated variations in source cliff responses; (ii) possible variations in the triggering m..