Portuguese Bend Landslide
...while "The Creepy Landslides of Portuguese Bend" may sound like the title of a horror movie, it describes a real phenomenon that exists in nature and confronts people and institutions.
So writes Dr. Robert Douglas, RPV resident and author of Special Publication Number 24 to the Association of Environmental and Engineering Geologists, about the collection of slope failures (landslides) that dominate the central portion of the City's southern slopes. Reactivated landslides within the greater Ancient Altamira Landslide Complex, which encompasses over two of the City's roughly fourteen square miles, move at rates between hundredths of an inch per year and tens of feet per year. This movement is especially noticed by motorists, cyclists and pedestrians who travel along Palos Verdes Drive South. Furthermore, they present a challenge to City Public Works staff who are tasked with maintaining safe access through this area. Portions of the landslide have been incorporated into Geologic Hazard Abatement Districts, in which the City participates as a land owner. These districts work to slow land movement through both policy and physical solutions. Elimination of septic systems, installation of dewatering wells, and control of storm water are some of the measures used.
In addition, the City works hard to maintain a safe roadway through the area at a cost of about a half million dollars per year. Regular travelers through the area are familiar with the frequent need to repair cracks and smooth out the roadway. The costs to "stop" the land from moving are incalculable, even if the technology existed to make that happen. Since it does not, the City does its best to "manage" our activity in the face of the nature's processes that are indeed very real.
- Portuguese Bend Landslide (PDF)
- 1997 Analysis of Landslide Material Loss (PDF)
- City Council Landslide Workshop July 31, 2012 (PDF)
- 1989 Final Environmental Report_AB Cove Landslide Stabilization Project (PDF)
- 1989 AB Cove Offshore Survey by Dill GeoMarine Consultants (PDF)
- 1957 Report of Earth Movement - Portuguese Bend (PDF)