Areas that are generally prone to landslide hazards:

• On existing old landslides.
• On or at the base of slopes.
• In or at the base of minor drainage hollows.
• At the base or top of an old fill slope.
• At the base or top of a steep cut slope.
• Developed hillsides where leach field septic systems are used

Areas that are typically considered safe from landslides:

• On hard, non-jointed bedrock that has not moved in the past.
• On relatively flat-lying areas away from sudden changes in slope angle.
• At the top or along the nose of ridges, set back from the tops of slopes.

Features that might be noticed prior to major landsliding:

• 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.
• Tilting or cracking of concrete floors and foundations.
• Broken water lines and other underground utilities.
• Leaning telephone poles, trees, retaining walls or fences
• Offset fence lines.
• Sunken or down-dropped road beds.
• Rapid increase in creek water levels, possibly accompanied by increased turbidity (soil content).
• Sudden decrease in creek water levels though rain is still falling or just recently stopped.
• Sticking doors and windows, and visible open spaces indicating jambs and frames out of plumb.

What to do if you suspect imminent landslide danger:

• Contact your local fire, police or public works department.
• Inform affected neighbors
• Evacuate

For further information on landslides in your area:

• Contact your County Geologist--Some cities also staff geologists.
• Contact your State Geologist or Engineer
• If a very detailed site analysis is desired, contract with a private consulting company specializing in earth movement Such companies would likely be those specializing in geotechnical engineering, structural engineering, or civil engineering. Your, Local, state, or county geologist could possibly advise you as to the best kind of professional to contact.

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