What is a landslide hazard map?
What is a landslide hazard map?
These maps might be as simple as a map that uses the locations of old landslides to indicate potential instability, or as complex as a map incorporating probabilities based on variables such as rainfall, slope angle, soil type, and levels of earthquake shaking. …
How can you identify if your area is prone to landslide?
Landslide Warning Signs
- Springs, seeps, or saturated ground in areas that have not typically been wet before.
- New cracks or unusual bulges in the ground, street pavements or sidewalks.
- Soil moving away from foundations.
- Ancillary structures such as decks and patios tilting and/or moving relative to the main house.
What does red color mean in the landslide hazard map?
Landslide Map: This map shows the distribution of relative landslide incidence and susceptibility across the conterminous United States. Red areas have the highest rates of landslide incidence. Pink areas have high rates of landslide incidence and susceptibility.
Where are landslide hazards the greatest?
The Appalachian Mountains, the Rocky Mountains and the Pacific Coastal Ranges and some parts of Alaska and Hawaii have severe landslide problems. Any area composed of very weak or fractured materials resting on a steep slope can and will likely experience landslides.
How is landslide hazard map prepared?
Preparation of a landslide inventory map is the basic approach of landslide hazard mapping. By the help of aerial photo interpretation, field survey, historical data of landslide occurrences and literature collection help to prepare landslide inventory map.
What do the legends show in earthquake induced shallow landslide map?
Earthquake-Induced Shallow Landslides Map (Refer to the picture) The legend tells you the levels of the danger of the occurrence of landslide. For example, majority of the provinces in the Northern Luzon is considered a high-danger zone.
Where are the areas of moderate susceptibility to landslide?
The Moderate landslide susceptibility area (Yellow regions in Figure 6) has slopes ranging between 21°-37°. These slopes are moderately steep to steep.
What are the color for landslide prone areas?
Carlos Tayag, MGB Ilocos director, said the color codes for landslides are red for highly susceptible areas, green for moderate susceptibility and yellow for low susceptibility.
What is the pink of a geological landslide area?
Open ovals represent landslides in the landslide inventory, with different colors representing different sources of information (yellow for CGS mapping). Solid pink area is the landslide susceptibility area; compare this area to the geology map.
Why are there so many landslides in Oregon?
Researchers at the University of Washington, Portland State University and the University of Oregon have shown that deep-seated landslides in the central Oregon Coast Range are triggered mostly by rainfall, not by large offshore earthquakes. Heavy rains are known to cause landslides that can be disruptive and deadly.
Which of the following locations is most likely to have a landslide?
Slides can occur in all 50 states, but regions like the Appalachian Mountains, the Rocky Mountains and the Pacific Coastal Ranges have “severe landslide problems,” according to the USGS. The agency lists California, Oregon, Washington, Alaska and Hawaii as especially prone.
What would be the purpose of making a landslide hazard map of an area?
A landslide hazard map can be prepared early in the planning study and developed in more detail as the study progresses. It can be used as a tool to help identify land areas best suited for development by examining the potential risk of landsliding.
What does it mean to have a landslide hazard map?
Landslide hazard maps indicate the possibility of landslides occurring throughout a given area. An ideal landslide hazard map shows not only the chances that a landslide may form at a particular place, but also the chance that it may travel downslope a given distance.
What to do if there is a landslide in your area?
The model is intended for use as a shallow landslide forecasting tool for use by city and county emergency managers. The map is not predictive, nor does it forecast the potential for deep-seated landslides. If a landslide occurs, evacuate the area and contact your local emergency management agency.
Is it possible to predict when a landslide will occur?
The data on this site cannot be used to predict definitely that landslides will or will not occur; it is intended to show the relative hazard of occurrence. For example, landslides may occur in regions under an ‘advisory’ and may not occur in all or any regions under a ‘warning’.
What are three factors that determine landslide susceptibility?
Prior failure (from a landslide inventory), rock or soil strength, and steepness of slope are three of the more important site factors that determine susceptibility. Examples of landslide susceptibility maps:
