Rock fall dynamics and deposition: an integrated analysis of the 2009 Ahwiyah Point rock fall, Yosemite National Park, USA

A comprehensive analysis of the 2009 Ahwiyah Point rock fall in Yosemite National Park revealed that large, energetic rock falls tend to flatten talus slopes, contrary to the steepening effect observed with smaller boulder accumulations. The study integrated airborne and terrestrial LiDAR, high-resolution photography, seismic, and acoustic data to reconstruct the event, which involved a 46,700 m³ rock block that fell 730 meters, triggering secondary impacts and remobilizing existing talus. Dynamic compaction of pulverized debris was identified as a key factor in the lower porosity of fresh talus compared to typical blocky talus slopes. Additionally, seismic and acoustic instruments proved effective for monitoring rock fall events, highlighting their potential for generalized rock fall surveillance.

Zimmer, V. L., Collins, B. D., Stock, G. M., & Sitar, N. (2012). Rock fall dynamics and deposition: an integrated analysis of the 2009 Ahwiyah Point rock fall, Yosemite National Park, USA. Earth Surface Processes and Landforms, 37(6), 680–691. Portico. https://doi.org/10.1002/esp.3206