New device installed near Matai'an barrier lake to boost monitoring

Taipei, Dec. 7 (CNA) A microseismometer was installed near the Matai'an Creek barrier lake in Hualien County on Sunday to strengthen monitoring of landslides and potential flood surges in the wake of an overflow that triggered deadly flooding in September.

The instrument, installed by a four-member team from National Yang Ming Chiao Tung University (NYCU), was airlifted to a slope about one kilometer south of the lake by a National Airborne Service Corps helicopter, the Forestry and Nature Conservation Agency (FANCA) said.

Microseismometers detect ground vibrations triggered by landslides, enabling real-time alerts and helping determine whether debris has blocked the creek or if a barrier lake dam is about to overflow, the agency said.

Because the device can also capture vibrations generated by actual water outflows or dam bursts and operates in all weather conditions, it complements two existing downstream microseismic stations and forms a more complete early-warning system, the agency said.

The laboratory of NYCU associate professor Weian Chao (趙韋安), who led the team that installed the device, first detected a major landslide in the area on July 21, making it the earliest team to identify the event, the agency said.

His group has since assisted in surveying and monitoring work in the area, the agency said, which noted that the barrier lake currently holds an estimated 291,000 cubic meters of water over an area of about 8 hectares.

Since the Sept. 23 overflow, the water level elevation has dropped by about 133 meters, and while the spillway remains stable, roughly 100 million cubic meters of sediment remains on the left bank, posing a risk of renewed blockage if an earthquake or heavy rain occurred, the agency said.