A NEW DATABASE OF LARGE-SCALE BEDROCK LANDSLIDES IN NEVADA, USA

Nevada is one of the most mountainous states in the USA. The mountain ranges are a result of active tectonics, including Basin and Range extension, Walker Lane translation, and widespread Cenozoic volcanism. The topographic relief across the state makes Nevada a prime candidate for landslide hazard. However, no database of landslides has been complied for the state to help assess landslide risk. We therefore built a database of known bedrock landslides across Nevada.

For the initial database, we focused on large-scale landslides (with deposits generally covering >1 km²). Landslide deposit polygons were combined from existing USGS and Nevada Bureau of Mines and Geology maps. For each landslide, we also collected data on source lithology, deposit morphometrics, and fault proximity. Approximately 500 large-scale landslides have been identified and documented across the state, though many of these are slide complexes that include multiple failure events. Estimates of the minimum number of failure events were documented for each polygon. Several different types of large-scale landslides are within the list, including rock avalanches, gravity slides, caldera collapse breccias, and rotational slumps.

These data have been integrated into a new map layer that will be available through the MyHAZARDS and MyPLAN web mapping applications, hosted by the Nevada Bureau of Mines and Geology. The map layer will be released in fall 2020, available via the Nevada Bureau of Mines and Geology open data site and interactive ArcGIS web application. These collected landslide data will be valuable to researchers, emergency managers, and the general public.