What are my risks?

• What areas are prone to landslides?
• Recent Kauai Landslides

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What areas are prone to landslides?

Areas generally more prone to landslides are those located at:

SOURCE: State of California Department of Conservation, Sacramento, CA and National Landslide Information Center, U.S. Geological Survey, Denver, CO

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Recent Kauai Landslides

Soil avalanches: In Hawaii, valley walls are typically covered by soil which is held to the bedrock by plant roots. We can find soil avalanches or landslides taking place on the western side or even northern side of Kauai.

Soil avalanches may leave bright scars on the hillside for months. A good example is a slide which occurred in Olokele Canyon on Kauai in October, 1981. The slide face was about 300 meters wide and about 800 meters high. That's a thousand feet wide by 2,400 feet high, a slide of tremendous proportions.

This particular slide was caused by a combination of high rainfall and underground water seepage. Features like this or processes like this are responsible for much of the valley development here in Hawaii.

Slow earth movement: One other thing to note is that soil creep is not a dramatic process but especially important. It's a slow, imperceptible, continuous process where the movement may be only a centimeter or so per year, but it is a very important process, and it's especially important in housing and commercial developments.

Hillside cut: Here where houses are built on the side of the hill, even very slow movements may cause the house to break. It may cause telephone poles to bend very slowly. It may cause fences to move.

Road cuts: How many times have we seen landslides along road cuts? The Department of Transportation mitigates landslides near roadways by erecting chicken wire strapped around the edge of the cliff. The purpose of this is to prevent rockfalls and other things from sliding out onto the highway.