California is well-known for being susceptible to landslides and carries a substantial share of the nation’s landslide risk due in part to it’s high population and the concentration of infrastructure in areas with substantial landslide hazard.
Deep Seated Landslides
Deep seated landslides in California generally occur due to precipitation, and to a lesser extent, earthquakes. Historically, large winter storms have caused the most damage, occurring towards the end of the winter season (March, April, May) due to the time it takes for seasonal rainfall to reach the bottom, “slip surface” of the landslide. However, heavy rain earlier in the season can also have this effect. These landslides are often generated by prolonged above-average rainfall, such as can occur during El Niño years, although even “normal” precipitation years in northern and central California can lead to landslide initiation. Often, deep seated landslides lay dormant for lengthy periods of time.
On the most basic level, weak rocks and steep slopes are more likely to generate landslides. A landslide occurs because the force of gravity becomes greater than either the forces of friction or the internal strength of the rock, soil, or sediment. The addition of water to material on a slope can make landslides more common. This is because water adds significant weight to the slope as it seeps into the ground, becoming groundwater, and adding to the gravitational force. Water also lowers the strength of the material which can make it less able to withstand the force of gravity. Water also reduces friction making it easier to move material downhill.
With years of Geo Construction Experience Groundforce can repair or stabilize any deteriorating or failed slope. We provide slope stabilization services for San Diego, Los Angeles, Riverside, Orange County and Southern California.
1220 PRESIOCA ST.
SPRING VALLEY, CA 91977