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Landslide Basics

Landslides occur in all 50 states and territories and they affect lives, property, infrastructure, and the environment.  Understanding when, where, and how landslides occur can help to reduce the risk of living with these natural hazards.  

What is a landslide?

rocks, dirt, and shrubs on hillside

Landslides occur in all 50 states and territories where they affect lives, property, infrastructure, and the environment.  Landslides are the downslope movement of earth materials (rock, debris, and soil) at rates that range from inches per year to tens of miles per hour. Some landslides can move faster than a person can run. Landslides can happen with no notice or can take place over a period of days, weeks, or longer.  

Mud Creek slide seen from the air on February 22 2024


Where do landslides occur?

Landslides occur in every state and U.S. territory including the Appalachian Mountains, the Rocky Mountains, the Pacific Coastal Ranges, and some parts of Alaska and Hawaii. Any area composed of very weak or fractured materials resting on a steep slope can and will likely experience landslides.

mud and vegetation on hillslopes above houses


Why do landslides occur?

Landslides occur when forces that form them overcome forces resisting their formation. 

two cracks on a gravel slope in residential yard


What are the signs of landslide development/movement? 

Landslides are dangerous and very difficult to predict. Some landslides may provide clues that they are about to happen; others may happen suddenly without any warning signs.


Why should I care about landslides?

Landslides kill people and destroy property.

severe damage to home foundation, homes built on landslide

How do I prepare for a landslide?

If you live on or below a slope, here are some simple steps you can take to identify a landslide hazard and reduce your landslide risk.

Center map shows landslide locations. Hills slope from sides down to center of figure with descriptive labels and arrows.
The University of Puerto Rico Mayagüez, the Natural Hazards Center at the University of Colorado Boulder, and the USGS Landslide Hazards Program collaborated to create educational materials for residents of Puerto Rico to learn about how to prepare for, mitigate, respond to, and recover from landslides. Pages from “Landslide Guide for Residents of Puerto Rico “ are shown in this figure. 


What do I do after a landslide has occurred?

Depending on the severity of the landslide, you may not be able to return home right away. If authorities say it is safe to return to your home, continue to be prepared to leave the area immediately if you observe unusual activity. 

home damaged by a landslide