Yosemite Valley poses significant rockfall hazard and related risk
due to its glacially steepened walls and approximately 4 million
visitors annually. To assess rockfall hazard, it is necessary to
evaluate the geologic structure that contributes to the destabilization
of rockfall sources and locate the most probable future source areas.
Coupling new remote sensing techniques (Terrestrial Laser Scanning,
Aerial Laser Scanning) and traditional field surveys, we investigated
the regional geologic and structural setting, the orientation of
the primary discontinuity sets for large areas of Yosemite Valley,
and the specific discontinuity sets present at active rockfall sources.
This information, combined with better understanding of the geologic
processes that contribute to the progressive destabilization and
triggering of granitic rock slabs, contributes to a more accurate
rockfall susceptibility assessment for Yosemite Valley and elsewhere.