Hazard and Risk Assessments

Landslide hazard and risk assessments help people understand the dangers from landslides to their towns and cities, homes, facilities, and businesses. Landslide hazard assessments are estimates of the probability that landslides will affect a particular area or location, typically within a given timeframe.

To reduce landslide hazard and risk, thorough understanding and readily useable tools are needed to better forecast landslide magnitude and mobility.

We are conducting research, rapid response, and information efforts to improve understanding of landslide initiation and reactivation processes through a combination of field monitoring, mapping and subsurface exploration, experimental studies, and theoretical analyses.

A large steep slope in the Barry Arm fjord 30 miles (50 kilometers) northeast of Whittier, Alaska has the potential to fall into the water and generate a tsunami that could have devastating local effects on those who live, work, and recreate in and around Whittier and in northern Prince William Sound.

The USGS led the efforts to produce landslide hazard maps for the main island of Puerto Rico following Hurricane Maria. These maps are today used by planners for land use decisions and emergency managers for hazard mitigation plans. To reduce loss from future landslides, the USGS and the University of Puerto Rico-Mayagüez instrumented 15 slopes across the main island and share near real-time data...

The USGS seeks to provide effective situational awareness about long-term and ongoing hazardous events to improve emergency response, inform the public, and minimize societal disruption. Large, highly mobile landslides generate seismic signals that can be detected by seismic monitoring networks and leave scars and deposits that can be detected from high-resolution remote-sensing imagery. Following...

Once the smoke clears from a wildfire, the danger is not over!! Other hazards, such as flash floods and debris flows, now become the focus. Areas recently burned by wildfires are particularly susceptible to flash floods and debris flows during rainstorms.

Estimates of the probability and volume of debris flows that may be produced by a storm in a recently burned area, using a model with characteristics related to basin shape, burn severity, soil properties, and rainfall. Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS...

Landslide Susceptibility Data and Maps provide tools for hazard assessment prior to an event that may cause landslides.