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Combining Distributed Acoustic Sensing and Beamforming in a Volcanic Environment on Mount Meager, British Columbia.

Session: Fiber-Optic Seismology I

Type: Oral

Date: 4/23/2021

Presentation Time: 10:30 AM Pacific

Description: 

We present one of the first applications of Distributed Acoustic Sensing (DAS) in a volcanic environment. There are two main goals: (1) To search for active volcanic signals of Mount Meager to study the volcanic complex, and (2) to study the feasibility of DAS as a tool in a remote and extreme environment.

The Mount Meager massif is an active volcanic complex in British Columbia that is estimated to have the largest geothermal potential in Canada and caused its largest recorded landslide in 2010. Climate change is thinning the glacier on top of Mount Meager, which may further destabilize the complex. We installed 3 km of fiber-optic cable at 2000 m elevation that crosses an alpine ridge and traverses the uppermost part of a glacier, yielding continuous measurements from 19 September to 17 October 2019.

We identify ~30 low-frequency (0.01-1 Hz) and 3000 high-frequency (5-45 Hz) events. The low-frequency events are not correlated with microseismic ocean or atmospheric noise sources. The frequency-power distribution of the high-frequency events indicate a natural origin, and beamforming on these events reveals distinct event clusters, predominantly in the direction of the main peaks of the complex. We hypothesize that the low-frequency events are volcanic tremor and that clusters of high-frequency events are also caused by volcanic activity.

The large data quantities of DAS enable most of our analysis, and this quantity outweighs the limitations due to the lower quality of individual channels and the limited aperture of the array when compared to conventional seismic arrays. We conclude that DAS holds promise to study volcanoes and warrants further developments in volcano seismology.

Presenting Author: Sara A. Klaasen

Student Presenter: Yes

Authors