Publications

Active landslides throughout the states and territories of the United States result in extensive property loss and 25-50 deaths per year. The U.S. Geological Survey (USGS) has a long history of detailed examination of landslides since the work of Howe (1909) in the San Juan Mountains of Colorado. In the last four decades, landslide inventory maps and landslide hazard maps have depicted...

Landslides, particularly debris flows, have long been a significant cause of damage and destruction to people and property in the Puget Sound region. Following the years of 1996 and 1997, the Federal Emergency Management Agency designated Seattle as a “Project Impact” city with the goal of encouraging the city to become more disaster resistant to landslides and other natural hazards. A...

Empirical rainfall thresholds and related information form the basis of a prototype system for forecasting landslides in the Seattle area. The forecasts are tied to four alert levels, and a decision tree guides the use of thresholds to determine the appropriate level. From analysis of historical landslide data, we developed a formula for a cumulative rainfall threshold (CT), P3  =  88.9...

In Seattle, Washington, deep-seated landslides on bluffs along Puget Sound have historically caused extensive damage to land and structures. These large failures are controlled by three-dimensional (3-D) variations in strength and pore-water pressures. We assess the slope stability of part of southwestern Seattle using a 3-D limit-equilibrium analysis coupled with a 3-D groundwater flow...

[No abstract available]

Dynamic stresses generated by earthquakes can trigger landslides. Current methods of landslide analysis such as pseudo-static analysis and Newmark's method focus on the effects of earthquake accelerations on the landslide mass to characterize dynamic landslide behaviour. One limitation of these methods is their use Mohr-Coulomb failure criteria, which only accounts for shear failure, but...

The largest-magnitude earthquake in the past 20 years struck near Mt. Carmel in southeastern Illinois on Friday morning, 18 April 2008 at 09:36:59 UTC (04:37 CDT). The Mw 5.2 earthquake was felt over an area that spanned Chicago and Atlanta, with about 40,000 reports submitted to the U.S. Geological Survey (USGS) “Did You Feel It?” system. There were at least six felt aftershocks greater...

Prediction of the runout distance of a debris flow is an important element in the delineation of potentially hazardous areas on alluvial fans and for the siting of mitigation structures. Existing runout estimation methods rely on input parameters that are often difficult to estimate, including volume, velocity, and frictional factors. In order to provide a simple method for preliminary...

Application of transient deterministic shallow landslide models over broad regions for hazard and susceptibility assessments requires information on rainfall, topography and the distribution and properties of hillside materials. We survey techniques for generating the spatial and temporal input data for such models and present an example using a transient deterministic model that...

As landslides continue to be a hazard that account for large numbers of human and animal casualties, property loss, and infrastructure damage, as well as impacts on the natural environment, it is incumbent on developed nations that resources be allocated to educate affected populations in less developed nations, and provide them with tools to effectively manage this hazard. Given that...

During spring 2006, talus from the toe area of a rock-block slide of about 800,000 m3 buried California State Highway 140, one of the main routes into heavily-visited Yosemite National Park, USA. Closure of the highway for 92 days caused business losses of about 4.8 million USD. The rock slide, composed of slate and phyllite, moved slowly downslope from April to June 2006, creating a...

The idea for Landslides and Engineering Geology of the Seattle, Washington, Areagrew out of a major landslide disaster that occurred in the Puget Sound region at the beginning of 1997. Unusually heavy snowfall in late December 1996 followed by warm, intense rainfall on 31 December through 2 January 1997 produced hundreds of damaging landslides in communities surrounding Puget Sound. This...