Acoustic Emission/Microseismic Activity

Hardy, H. Reginald

doi:10.1201/9780203971109

Cited by 116 publications

(38 citation statements)

References 4 publications

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“…Acoustic emissions and microseismic signals are elastic waves generated by the rapid release of energy within a material (Hardy, 2003), mostly caused by mechanical loading and related to an increase in material damage (Lockner et al, 1991;Scholz, 1968), such as crack formation, fracture propagation, failure of intact rock bridges, friction between rock blocks, or grain motion/rearrangements in granular materials. Detection of AE and MS are not distinct techniques, but are usually referring to different frequency domains: AE refers to acoustic signals in the higher sonic and ultrasonic range: 1 kHz to 1 MHz (Ohnaka & Mogi, 1982).…”

Section: Acoustic Emissions and Microseismic Measurementsmentioning

confidence: 99%

Acoustic and Microseismic Characterization in Steep Bedrock Permafrost on Matterhorn (CH)

et al. 2018

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Understanding of processes and factors influencing slope stability is essential for assessing the stability of potentially hazardous slopes. Passive monitoring of acoustic emissions and microseismology provides subsurface information on fracturing (timing and identification of the mechanism) and therefore complement surface displacement data. This study investigates for the first time acoustic and microseismic signals generated in steep, fractured bedrock permafrost, covering the broad frequency range of 1 − 105 Hz. The analysis of artificial forcing experiments using a rebound hammer in a controlled setting led to two major findings: First, statistically insignificant cross correlation between signals indicates that waveforms change strongly with propagation distance. Second, a significant amplification is found in the frequency band 33–67 Hz. This finding is strongly supported by evidence from artificial rockfall events and more importantly by naturally occurring fracture events identified in fracture displacement data. Thus, filtering this frequency band enables enhanced detection of microseismic events relevant for slope stability assessment. The analysis of 2‐year time series in this frequency band further suggests that the detected energy rate baseline of all automatically triggered events using the STA/LTA algorithm is not sensitive to temperature forcing, an observation of primary importance for long‐term data collection, analysis, and interpretation. The event detection in the established frequency band is not only improved but also not affected by the short‐ and long‐term temperature changes in such a rapidly changing environment.

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Section: Acoustic Emissions and Microseismic Measurementsmentioning

confidence: 99%

Acoustic and Microseismic Characterization in Steep Bedrock Permafrost on Matterhorn (CH)

et al. 2018

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“…To simplify the discussion, only the Cumulative AE Energy (the sum of the energy emitted by all events observed during a specific period of time), was used as the principal parameter for quantifying emission data. This choice was not accidental; AE workers recognise AE energy as the most suitable parameter to describe the behaviour of materials under stress (Hardy, 2003;Pollock, 1977).…”

Section: Acoustic Emission Datamentioning

confidence: 99%

Swelling and acoustic emission behaviour of unconfined and confined coal during sorption of CO2

Majewska

Majewski

Ziętek

2013

International Journal of Coal Geology

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Section: Introductionmentioning

confidence: 99%

“…The illustration considers values in a general sense and for an illustrative purpose only; different geological settings may result in different relationships between these parameters. Modified after Hardy (2003), Kwiatek et al (2011), Zoback and Gorelick (2012), and Eaton et al (2018). minerals, and hydrocarbons, while regional and global earthquakes are used in earthquake seismology to characterize fault zones and the deeper interior (down to 100 km or more; Gibowicz & Kijko, 1994;Stein & Wysession, 2003;Yilmaz, 2015;Ikelle & Amundsen, 2018).…”

Section: Introductionmentioning

confidence: 99%

Recent Advances and Challenges of Waveform‐Based Seismic Location Methods at Multiple Scales

Tan

Schwarz

et al. 2020

Reviews of Geophysics

132

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Source locations provide fundamental information on earthquakes and lay the foundation for seismic monitoring at all scales. Seismic source location as a classical inverse problem has experienced significant methodological progress during the past century. Unlike the conventional traveltime‐based location methods that mainly utilize kinematic information, a new category of waveform‐based methods, including partial waveform stacking, time reverse imaging, wavefront tomography, and full waveform inversion, adapted from migration or stacking techniques in exploration seismology has emerged. Waveform‐based methods have shown promising results in characterizing weak seismic events at multiple scales, especially for abundant microearthquakes induced by hydraulic fracturing in unconventional and geothermal reservoirs or foreshock and aftershock activity potentially preceding tectonic earthquakes. This review presents a comprehensive summary of the current status of waveform‐based location methods, through elaboration of the methodological principles, categorization, and connections, as well as illustration of the applications to natural and induced/triggered seismicity, ranging from laboratory acoustic emission to field hydraulic fracturing‐induced seismicity, regional tectonic, and volcanic earthquakes. Taking into account recent developments in instrumentation and the increasing availability of more powerful computational resources, we highlight recent accomplishments and prevailing challenges of different waveform‐based location methods and what they promise to offer in the near future.

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Acoustic Emission/Microseismic Activity

Cited by 116 publications

References 4 publications

Acoustic and Microseismic Characterization in Steep Bedrock Permafrost on Matterhorn (CH)

Acoustic and Microseismic Characterization in Steep Bedrock Permafrost on Matterhorn (CH)

Swelling and acoustic emission behaviour of unconfined and confined coal during sorption of CO2

Recent Advances and Challenges of Waveform‐Based Seismic Location Methods at Multiple Scales

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