Deep-Seated Taiwan Landslide Reveals Hidden "Stick-Slip" Movements Captured Via Borehole Fiber Optic Sensors

Scientists use borehole fiber optics at Taiwan's Lantai site to detect deep "stick-slip" events, linking typhoon rain to potential catastrophic landslide failures.

By: AXL Media

Published: Apr 18, 2026, 10:38 AM EDT

Source: Information for this report was sourced from EurekAlert!

Revolutionizing Landslide Subsurface Observation

For the first time, scientists have successfully "seen" the high-resolution internal mechanics of a deep-seated landslide using a fiber optic cable deployed deep into a borehole. At the Lantai site in northern Taiwan, this technology has captured minute, periodic "stick-slip" events—small, jerky movements that occur along the shear zone where the sliding mass meets the stable bedrock. Previously, these movements were nearly impossible to detect without surface-level instrumentation, but the new borehole sensing method provides a direct view into the complex friction and movement occurring far below the surface.

Persistent Nature Of Micro-Slip Events

Traditionally, stick-slip events in landslides were considered rare, episodic precursors that only appeared immediately before a catastrophic failure. However, Hsin-Hua Huang of Academia Sinica reported at the 2026 Seismological Society of America (SSA) Annual Meeting that these events are actually persistent. They occur continuously but are simply too small to be measured by traditional surface sensors under normal conditions. This discovery suggests that deep landslides are in a state of constant, micro-scale adjustment, rather than remaining static until a major environmental trigger occurs.

Distributed Acoustic Sensing As A Thousands-In-One Tool

The breakthrough relies on Distributed Acoustic Sensing (DAS), a technique that transforms a standard fiber optic cable into a dense array of thousands of individual seismic sensors. By sending laser pulses down the cable and measuring the light reflected off tiny internal flaws in the glass, an "interrogator" instrument can detect microscopic strain and vibrations along the entire length of the fiber. Compared to traditional geophysical tools, DAS is significantly more cost-effective and easier to deploy at the extreme depths necessary to reach the landslide’s critical failure plane.