In a striking discovery, NASA scientists have found that the long-active landslide zone on the Palos Verdes Peninsula is expanding at an alarming rate.
Advanced radar analysis has revealed that land in the residential area moved up to 4 inches (10 cm) per week during a four-week period in the fall of 2024.
This rapid motion threatens homes, infrastructure, and the very stability of the peninsula itself.
A Decades-Old Landslide That Won’t Stop
The Palos Verdes Peninsula, which juts into the Pacific Ocean just south of Los Angeles, has long been known for its unstable ground.
Landslides in this region have been creeping toward the ocean for at least 60 years, affecting hundreds of buildings and reshaping the coastline.
However, after record-breaking rainfall in 2023 and heavy precipitation in early 2024, the rate of movement has accelerated dramatically, and the active area has expanded.
NASA’s Jet Propulsion Laboratory (JPL) in Southern California has been closely monitoring these changes.
Researchers used data from an airborne radar system, mounted on a Gulfstream III jet, to measure the landslide’s motion and provide a clearer picture of its evolving risk profile.
How NASA Measured the Movement
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA employed radar data collected from four flights of the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument between September 18 and October 17, 2024.
By analyzing multiple passes of the radar, scientists estimated both the speed and direction of the sliding landmass.
- Dark red zones in the imagery indicate the fastest-moving areas.
- Arrows show the direction of movement.
- White lines outline the previous landslide boundaries as defined in 2007 by the California Geological Survey.
“The footprint of land experiencing significant impacts has expanded, and the speed of movement is more than enough to put human life and infrastructure at risk,” said Alexander Handwerger, a JPL landslide scientist leading the study.
Landslides Are Not Always Slow
There’s a common belief that slow-moving landslides are predictable and pose minimal danger compared to sudden collapses. However, this new data challenges that assumption. The Palos Verdes Peninsula has shown that long-term movements can accelerate unexpectedly, creating imminent hazards even in areas thought to be stable.
While small, slow shifts may seem harmless, the cumulative effects can cause cracks in roads, weakened foundations, and water line failures, ultimately leading to catastrophic damage.
The fact that this landslide zone is picking up speed raises urgent concerns for residents, engineers, and local authorities.
The Future of Landslide Monitoring
The ARIA team didn’t just rely on airborne radar. They also integrated data from the European Space Agency’s Copernicus Sentinel-1A/B satellites, which provide continuous satellite-based monitoring of ground deformation.
These findings were shared with California state officials to aid in emergency response efforts and are now available to the public via NASA’s Disaster Mapping Portal.
Handwerger is also leading NASA’s Landslide Climate Change Experiment, an upcoming mission that will use advanced airborne radar to study how extreme precipitation patterns—whether excessively wet or dry—affect landslides along the California coastline.
More About ARIA & UAVSAR
The Advanced Rapid Imaging and Analysis (ARIA) project is a collaboration between NASA’s Jet Propulsion Laboratory (JPL) and Caltech, focusing on using radar and optical remote sensing, GPS, and seismic data to study natural disasters.
ARIA has been instrumental in analyzing earthquakes, volcanoes, landslides, wildfires, and subsurface fluid movements, providing critical insights for both scientific research and emergency response.
NASA’s UAVSAR has conducted thousands of flights since 2007, gathering data on glaciers, forests, and seismic activity, and is one of the agency’s most valuable tools for monitoring environmental changes around the world.
What’s Next for the Palos Verdes Peninsula?
The rapid movement of land on the Palos Verdes Peninsula highlights the growing threats posed by climate-driven geological activity.
As heavy rainfall events become more frequent due to climate change, the risk of landslides is expected to rise.
Ongoing monitoring using airborne and satellite radar will be essential in predicting future movements and preparing local communities for the challenges ahead.
For now, scientists and local authorities will continue to keep a close eye on this expanding landslide.
The question remains: how much more movement can the region withstand before serious infrastructure failures occur?
Stay tuned for updates as NASA continues its groundbreaking research into Earth’s shifting landscapes.
