California cliff collapses can be detected by sensors days in advance, study finds

On April 21, 2024, about 200 tons of material fell from cliffs in Del Mar, California. A report from scientists at the University of California - San Diego reveals that a network of sensors can detect impending cliff collapses hours to days before they occur. The study suggests that an early warning system could potentially save lives and protect infrastructure.

Study Highlights Early Warning Potential

The report, titled California Coastal Landslide Early Warning Research, indicates that advanced in-ground sensors provide reliable warnings of dangerous landslides. The findings, published in the Journal of Geophysical Research: Earth Surface, emphasize the need for further development to formalize these findings into an actionable warning system.

More than 70% of California's coastline consists of eroding cliffs, posing significant risks to public safety and infrastructure. These cliffs are vital for transportation and energy facilities, yet they can be deadly when collapses occur.

Technological Advancements in Monitoring

Researchers at the Scripps Institution of Oceanography, including coastal geomorphologist Adam Young and geophysicist Mark Zumberge, took a comprehensive approach to monitor cliff stability. They installed various sensors, including tiltmeters and extensometers, to measure ground movement with high precision.

Key locations for the study included:

• Beacon's Beach in Encinitas
• Railway Corridor in Del Mar
• San Elijo State Beach

These sites were chosen due to their history of landslides and the presence of critical infrastructure.

Legislative Support for Coastal Monitoring

The tragic landslide incident in August 2019 at Grandview Beach, which resulted in the deaths of three women, prompted California Assemblymember Tasha Boerner to advocate for enhanced coastal monitoring. She introduced Bill AB 66, securing funding to better understand bluff failure timing and to inform the development of an early warning system.

"Bluff collapses are a constant threat to coastal neighborhoods in my district and across the California coast... We can save lives, protect our coastal economy, and vital transportation networks in the face of sea-level rise with a bluff-collapse early warning notification system," said Boerner.

The study's results are crucial as coastal landslides are expected to increase due to factors like sea-level rise and population growth. Implementing an effective early warning system could mitigate risks associated with these natural hazards.