Distributed acoustic sensing of microseismic sources and wave propagation in glaciated terrain

F Walter,M Köpfli,F Lindner,M Chmiel,P Paitz,A Fichtner,D Gräff

doi:10.1038/s41467-020-15824-6

Abstract

Records of Alpine microseismicity are a powerful tool to study landscape-shaping processes and warn against hazardous mass movements. Unfortunately, seismic sensor coverage in Alpine regions is typically insufficient. Here we show that distributed acoustic sensing (DAS) bridges critical observational gaps of seismogenic processes in Alpine terrain. Dynamic strain measurements in a 1 km long fiber optic cable on a glacier surface produce high-quality seismograms related to glacier flow and nearby rock falls. The nearly 500 cable channels precisely locate a series of glacier stick-slip events (within 20–40 m) and reveal seismic phases from which thickness and material properties of the glacier and its bed can be derived. As seismic measurements can be acquired with fiber optic cables that are easy to transport, install and couple to the ground, our study demonstrates the potential of DAS technology for seismic monitoring of glacier dynamics and natural hazards.

Highlights

Records of Alpine microseismicity are a powerful tool to study landscape-shaping processes and warn against hazardous mass movements
Similar to applications in other seismological disciplines, distributed acoustic sensing (DAS) technology offers a vast potential for monitoring glacier dynamics and Alpine mass movements
Our results show that the DAS system is capable of recording seismogenic glacier flow and even small Alpine mass movements such as rockfalls

Summary

Introduction

Records of Alpine microseismicity are a powerful tool to study landscape-shaping processes and warn against hazardous mass movements. As seismic measurements can be acquired with fiber optic cables that are easy to transport, install and couple to the ground, our study demonstrates the potential of DAS technology for seismic monitoring of glacier dynamics and natural hazards. Seismic studies in Alpine terrain have cultivated new subdisciplines like environmental seismology[1] and cryoseismology[2,3]. This has filled critical observational gaps for investigation of mass movements such as bedload transport in torrents[4], rockfalls[5], debris flows[6], and avalanches[7] as well as the stability of rock structures[8] and landslides[9]. Advanced interferometric techniques applied to ultra-stable laser light injected into fiberoptic cables may even sample cables hundreds of kilometers long[14]

Methods

Results

Conclusion