Using Google Earth and Google Street View To Rate Rock Slope Hazards

Abstract

AbstractRockfall hazard from cut slopes along highways are caused primarily by unfavorable orientations of discontinuities, presence of unconsolidated cobble/boulder deposits, undercutting of strong rocks by weaker rocks, or degradation of weak rock masses. The rockfall hazard rating system (RHRS) was introduced in Oregon to evaluate the hazard and associated risk to an adjacent transportation facility for a cut slope's potential for releasing rockfalls. RHRS is a numerical score–based rating of parameters that characterize rockfalls. The parameters include slope geometry (height, angle, roughness, orientation), geologic information (discontinuity characterization, undercutting susceptibility), driver's line of sight, and climate. Geologic information, such as discontinuity orientation data, is traditionally collected using a transit compass and measuring tape at the site. The method is time consuming and expensive and can be dangerous. This study tests the use of Google Earth and Google Street View tools to remotely collect data for selected parameters that characterize rockfall hazard. The selected parameters are categorized under slope profile, geologic characteristics, and impact factor parameters, which are quantitatively and qualitatively measurable using Google Street View and Google Earth. A section of U.S. 33 with a high density of road cuts and two more sites along Interstate 64, all located in Virginia, were selected for the study. Sites were evaluated by using a combination of measurement tools available in Google Earth and a visual inspection of the rock units in Google Street View. The results of seven of the sites were re-evaluated using field-derived data.