NASA scientists have been tracking alarmingly accelerating landslides in California's Palos Verdes Peninsula, where land is sliding toward the ocean at a rate of up to 4 inches per week. Researchers used advanced airborne radar to map the movement of unstable terrain and found that the affected areas had expanded significantly, threatening homes and infrastructure.

Data captured by NASA's UAVSAR airborne radar instrument in the fall of 2024 shows the movement of landslides on the Palos Verdes Peninsula following record rainfall in Southern California in 2023 and another wet winter in 2024. Darker red indicates faster movement. Source: NASA Earth Observatory

NASA's Jet Propulsion Laboratory (JPL) in Southern California used airborne radar to track slow-moving landslides on the Palos Verdes Peninsula in Los Angeles County. Their analysis found that between September and October 2024, the land in the residential area was sliding toward the ocean at a rate of up to 4 inches (10 centimeters) per week.

The Palos Verdes Peninsula, south of Los Angeles and stretching into the Pacific Ocean, sits atop an ancient landslide complex that has been moving for at least 60 years. The movement affected hundreds of buildings in the area. The rate of landslides has accelerated in recent years, with active landslide zones expanding after record-breaking rainfall in 2023 and storms in early 2024.

To create this visualization, the Advanced Rapid Imaging and Analysis (ARIA) team used data from four NASA Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) flights conducted between September 18 and October 17. The UAVSAR instrument is mounted on a Gulfstream III jet and takes off from NASA's Armstrong Flight Research Center in Edwards, California, on four planned flights to estimate the landslide's three-dimensional velocity and direction.

In the image above, the colors indicate how quickly parts of the landslide moved in late September and October, with the darkest red indicating the fastest speed. Arrows represent the direction of horizontal movement. The solid white line is the boundary of the active landslide area identified by the California Geological Survey in 2007.

"In effect, we see that the area of ​​land that has been significantly impacted has expanded at a rate that could endanger human life and infrastructure," said JPL landslide scientist Alexander Handwerger, who conducted the analysis.

The insights from the drone's synthetic aperture radar flights are part of a package of analyzes by the ARIA team, which also used data from the European Space Agency's Copernicus Sentinel-1A/B satellites. The results of the analysis have been provided to California officials to support the state's landslide response and are available to the public on NASA's Hazard Mapping Portal.

Handwerger is also the principal investigator of NASA's upcoming Landslide Climate Change Experiment, which will use airborne radar to study how extremely wet or dry precipitation patterns affect landslides. The survey will include flights across the coastal slopes of the California coastline.

The Advanced Rapid Imaging and Analysis (ARIA) project is a collaboration between NASA's Jet Propulsion Laboratory (JPL) and the California Institute of Technology to use radar and optical remote sensing, global positioning system (GPS) and seismic data for scientific research and disaster response. ARIA focuses on monitoring and analyzing natural hazards, including earthquakes, volcanoes, landslides, wildfires and underground fluid movements, providing valuable insights for scientific understanding and emergency management.

Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) is a powerful airborne radar system that has flown thousands of missions around the world since 2007. UAVSAR is installed on a Gulfstream III aircraft and is used to study a variety of Earth processes, including glacial movement, ecosystem changes, and natural hazards such as earthquakes, volcanic activity, and landslides. Its high-resolution imaging capabilities make it an important tool for detecting subtle ground movements and assessing long-term changes in the environment.

Compiled from /ScitechDaily