STATISTICAL ANALYSIS OF LARGE-SCALE BEDROCK LANDSLIDES IN NEVADA, USA

Tectonism in Nevada has resulted in abundant large-scale (deposits covering >1 km²) landslide events with deposits present both on the surface and within the stratigraphic record. Most of these deposits are Miocene and younger; related to Basin and Range extension and strike-slip deformation within the Walker Lane. Some landslide deposits are older including those related to caldera collapse events during the Oligocene-Miocene ignimbrite flare-up, metamorphic core complexes, and older orogenic events. Still others occurred as failures around step-sided basalt-capped plateaus in the northern part of the state. However, it is not clear why large-scale landsliding is so prevalent within Nevada, nor what factors are more likely to produce large landslides.

In order to evaluate factors related to large-scale landslides in Nevada, I collected information on nearly 700 large-scale landslides across the state. Landslide were identified from USGS and Nevada Bureau of Mines and Geology maps. From these maps, I collected and tabulated data on several parameters, including age of the landslide, age of the slide material and substrate, lithology, flow direction, runout length, deposit width, length, and area, drop, number of sliding events (if known), and whether or not a fault is present. Style of failure was documented, including rock avalanches, rock rotational slides, rock planar slides, and caldera collapse breccias. These data are being analyzed both as an entire data set and broken smaller groupings, including geomorphic provinces (mafic plateaus, Walker Lane, modern Basin and Range, early Basin and Range, calderas, and core complexes) and style of failure. Analyses will include Kolmogorov-Smirnov tests and principal component analysis. Ultimately, these analyses, combined with on-going range-front digital elevation model analysis will shed light on key controlling factors in large-scale landsliding events within Nevada.