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Observing Southern California Landslides Using UAVSAR: La Conchita as a Case Study
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  • Nathan Pulver,
  • Andrea Donnellan,
  • Jay Parker,
  • Lindsay LaBrecque
Nathan Pulver
Jet Propulsion Laboratory
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Andrea Donnellan
Jet Propulsion Laboratory, California Institute of Technology & University of Southern California

Corresponding Author:andrea.donnellan@jpl.nasa.gov

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Jay Parker
Jet Propulsion Lab (NASA)
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Lindsay LaBrecque
Stanford University
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Abstract

The La Conchita Landslide is infamous for its repeated devastation of the coastal community in Southern California. The landslide caused severe damage and loss of life once in 1995 and 2005. In this study we use UAVSAR interferograms of the La Conchita area to identify any residual motion or slope instability associated with the landslides. UAVSAR is NASA’s airborne interferometric synthetic aperture radar (InSAR) platform and is useful for imaging changes in the Earth’s surface. UAVSAR repeat pass interferometry products show disturbances in the image pairs that may correlate with landslides, including where the La Conchita landslides had previously occurred. We used UAVSAR to compare different line-of-sight velocity profiles of the landslide to a stable area to the northeast. UAVSAR pairs show ongoing motion of up to -0.14 cm/day average velocity years after the landslides occurred. More stable areas show less than -0.06 cm/day maximum average velocity. The results imply that damaged rock and soil of a landslide continue to move relative to the surrounding more stable area. UAVSAR image pairs may be useful for identifying unstable areas on slopes that may be associated with landslides or other disturbances.