Similar terrestrial control mechanisms may also be relevant for other coastal chalk cliffs, in addition to already investigated marine triggers. Seasonal water availability, controlled by plant activity, imposed an annual cycle of cliff failure, and wetter and drier than average years imposed a month‐long legacy effect on cliff failure dynamics. Water content was modulated by (i) subsurface flow toward the cliff, (ii) rain onto the cliff, and (iii) condensation of atmospheric moisture, leading to clustered failures preferentially during the night. Most failures occurred when water caused a state transition of the cliff forming chalk, from solid to liquid. Instead, cliff failure was associated with terrestrial controls on rock moisture. We show that during the monitoring interval, marine processes were negligible as a trigger of cliff failure, although still being important for the removal of resulting deposits. The subminute precision of event timing allows the linkage of individual failures to triggers over a wide range of relevant time scales. Here we use seismic records and auxiliary data spanning 25 months to precisely identify and locate 81 failure events along the 8.6‐km‐long chalk cliff coast of Jasmund, on Germany's largest island, Rügen. Improved insight into direct links between cliff failure and forcing mechanisms requires precise information on the timing of individual failures, which is difficult to obtain with conventional observation methods for longer stretches of coastline. Narrative descriptions of events are contained in the database, but are also provided in a more readable Adobe portable document format (pdf) file (Yosemite_rock_fall_database_narratives_1857-2011.pdf) available for download separate from the database.Ĭliff failure is a fundamental process shaping many coastlines worldwide. The inventory database itself is contained in a Microsoft Excel spreadsheet (Yosemite_rock_fall_database_1857-2011.xlsx). The accompanying report describes each of the organizational categories in the database, including event location, type of slope movement, date, volume, relative size, probable trigger, impact to humans, narrative description, references, and environmental conditions. In addition to damaging roads, trails, and other facilities, rock falls and other slope movement events have killed 15 people and injured at least 85 people in the park since the first documented rock fall in 1857. Rock-fall hazard and risk are particularly relevant in Yosemite Valley, where glacially steepened granitic cliffs approach 1 km in height and where the majority of the approximately 4 million yearly visitors to the park congregate. Rock falls, rock slides, and other forms of slope movement represent a serious natural hazard in Yosemite National Park. The inventory database documents 925 events spanning the period 1857–2011. This report describes and presents the accompanying rock fall inventory database for Yosemite National Park, California. Further, inventories can assist in quantifying the relative hazard and risk posed by these events over both short and long time scales. For example, detailed information on rock falls is critical for identifying mechanisms that trigger rock falls, for quantifying the susceptibility of different cliffs to rock falls, and for developing magnitude-frequency relations. Inventories of rock falls and other types of landslides are valuable tools for improving understanding of these events.
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