SGER: Seismic Monitoring of Active Rock Fall Source Areas in the Yosemite National Park

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The unique setting of Yosemite National Park and the Yosemite Valley brings with it a significant risk of rocks falls impacting on major facilities and pathways used by thousands of visitors every year. A preliminary geophone and accelerometer deployment last winter captured a rock fall event demonstrating that of real time monitoring of rock falls is feasible. The objective of this project is to rapidly deploy a denser array of instruments in close vicinity (<30 m) of this active source area in order to asses the feasibility of being able to monitor rock noise associate with rock fall initiation and to determine if the instrument records can be used to localize the source of the noise, as is done in other seismic applications. This work has to be done in the summer in order to get safe access to the site. In addition, as time passes the probability of additional events decreases and, therefore, timely response is essential for success. Overall, this is a very high risk and high potential payoff effort that, if successful, could significantly change the way rock fall hazards are identified and monitored. The project has a significant broader impact in many aspects of public safety, since rock fall hazards are not confined just to national parks and Yosemite, in particular. The demonstration of the feasibility of rock fall hazard identification using real time instrumentation will have application in other areas such highway safety. In addition, not much is known about the real time behavior of fractured rock masses and the data should provide an excellent insight into long term rock mass behavior to climatic (temperature, humidity, pressure) changes. Also, having active science project in Yosemite National Park will provide an opportunity to educate the general public about the geology, seismology, and natural evolution of this spectacular landscape.