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

Walter, Fabian; Gräff, Dominik; Lindner, Fabian; Paitz, Patrick; Köpfli, Manuela; Chmiel, Małgorzata; Fichtner, Andreas

doi:10.1038/s41467-020-15824-6

Cited by 172 publications

(106 citation statements)

References 48 publications

(72 reference statements)

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“…Obviously, this would be costly and logistically challenging. However, novel instrumentation such as distributed acoustic sensing (DAS) (Booth et al, 2020; Walter et al, 2020) or seismic nodes would make this feasible. We suggest that one should use a spiral or similar network geometry, so as to have sufficient radial and azimuthal coverage of the study site to constrain source mechanisms.…”

Section: Resultsmentioning

confidence: 99%

Breaking the Ice: Identifying Hydraulically Forced Crevassing

Hudson

Brisbourne

White

et al. 2020

Geophysical Research Letters

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Hydraulically forced crevassing is thought to reduce the stability of ice shelves and ice sheets, affecting structural integrity and providing pathways for surface meltwater to the bed. It can cause ice shelves to collapse and ice sheets to accelerate into the ocean. However, direct observations of the hydraulically forced crevassing process remain elusive. Here we report a novel method and observations that use icequakes to directly observe crevassing and determine the role of hydrofracture. Crevasse icequake depths from seismic observations are compared to a theoretically derived maximum dry crevasse depth. We observe icequakes below this depth, suggesting hydrofracture. Furthermore, icequake source mechanisms provide insight into the fracture process, with predominantly opening cracks observed, which have opening volumes of hundredths of a cubic meter. Our method and findings provide a framework for studying a critical process that is key for the stability of ice shelves and ice sheets and, therefore, future sea level rise projections.

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Section: Resultsmentioning

confidence: 99%

Breaking the Ice: Identifying Hydraulically Forced Crevassing

Hudson

Brisbourne

White

et al. 2020

Geophysical Research Letters

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“…Recently DAS technology has been applied to studies of earth science in both on-land and under-sea regions and successfully detected seismic signals. For example, the DAS technique was applied to the on-land fiber-optic cable, and it detected surface waves that originated from regional to global teleseismic events 16 – 19 , an ice-quake event inside the glacier terrain 20 , and ice sheet displacement 21 . DAS can estimate subsurface structures using artificially controlled sources or ambient noise 22 , 23 .…”

Section: Introductionmentioning

confidence: 99%

Detection of hydroacoustic signals on a fiber-optic submarine cable

Matsumoto

Araki

Kojima

et al. 2021

Sci Rep

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A ship-based seismic survey was conducted close to a fiber-optic submarine cable, and 50 km-long distributed acoustic sensing (DAS) recordings with air-gun shots were obtained for the first time. We examine the acquired DAS dataset together with the co-located hydrophones to investigate the detection capability of underwater acoustic (hydroacoustic) signals. Here, we show the hydroacoustic signals identified by the DAS measurement characterizing in frequency-time space. The DAS measurement can be sensitive for hydroacoustic signals in a frequency range from $$10^{-1}\,\text {Hz}$$ 10 - 1 Hz to a few tens of Hz which is similar to the hydrophones. The observed phases of hydroacoustic signals are coherent within a few kilometers along the submarine cable, suggesting the DAS is suitable for applying correlation analysis using hydroacoustic signals. Although our study suggests that virtual sensor’s self-noise of the present DAS measurement is relatively high compared to the conventional in-situ hydroacoustic sensors above a few Hz, the DAS identifies the ocean microseismic background noise along the entire submarine cable except for some cable sections de-coupled from the seafloor.

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“…The first observations of earthquake-induced rotational ground motions by large ring laser gyroscopes [ 2 , 3 ], as well as the observation of crustal coseismic deformation during the Landers earthquake sequence in 1992 by long baseline strainmeters [ 4 ], certainly count to the major milestones in seismic wavefield gradient observation. However, only very recent developments of portable seismic rotation and strain sensors made the direct observations of seismic wavefield gradients possible for a broad range of applications, such as volcanology [ 5 , 6 , 7 ], ocean bottom seismology [ 8 , 9 , 10 ], structural health monitoring [ 11 , 12 , 13 ], seismic exploration [ 14 , 15 , 16 , 17 ], microzonation in urban environments [ 18 ], and glaciology [ 19 ]. The most commonly used technologies for seismic ground rotation sensing are fiber-optic Sagnac interferometry [ 20 ], micro-electro mechanical systems [ 21 ], small-scale finite differencing within a rigid configuration of translation sensors [ 22 ], and liquid-based electrochemical transducers [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Rotation, Strain, and Translation Sensors Performance Tests with Active Seismic Sources

Bernauer

Behnen

Wassermann

et al. 2021

Sensors

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Interest in measuring displacement gradients, such as rotation and strain, is growing in many areas of geophysical research. This results in an urgent demand for reliable and field-deployable instruments measuring these quantities. In order to further establish a high-quality standard for rotation and strain measurements in seismology, we organized a comparative sensor test experiment that took place in November 2019 at the Geophysical Observatory of the Ludwig-Maximilians University Munich in Fürstenfeldbruck, Germany. More than 24 different sensors, including three-component and single-component broadband rotational seismometers, six-component strong-motion sensors and Rotaphone systems, as well as the large ring laser gyroscopes ROMY and a Distributed Acoustic Sensing system, were involved in addition to 14 classical broadband seismometers and a 160 channel, 4.5 Hz geophone chain. The experiment consisted of two parts: during the first part, the sensors were co-located in a huddle test recording self-noise and signals from small, nearby explosions. In a second part, the sensors were distributed into the field in various array configurations recording seismic signals that were generated by small amounts of explosive and a Vibroseis truck. This paper presents details on the experimental setup and a first sensor performance comparison focusing on sensor self-noise, signal-to-noise ratios, and waveform similarities for the rotation rate sensors. Most of the sensors show a high level of coherency and waveform similarity within a narrow frequency range between 10 Hz and 20 Hz for recordings from a nearby explosion signal. Sensor as well as experiment design are critically accessed revealing the great need for reliable reference sensors.

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

Cited by 172 publications

References 48 publications

Breaking the Ice: Identifying Hydraulically Forced Crevassing

Breaking the Ice: Identifying Hydraulically Forced Crevassing

Detection of hydroacoustic signals on a fiber-optic submarine cable

Rotation, Strain, and Translation Sensors Performance Tests with Active Seismic Sources

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