Relative source location using coda-wave interferometry: Method, code package, and application to mining-induced earthquakes

Zhao, Youqian; Curtis, Andrew

doi:10.1190/geo2018-0601.1

Cited by 5 publications

(11 citation statements)

References 44 publications

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“…These results also show that in the case of simultaneous perturbations of source location and velocity, source separation can be estimated much more accurately than estimates of the change in velocity. Therefore, we would expect that the 3‐D network of relative locations of acoustic emissions that occur during deformation can be estimated robustly using laboratory data sets even if velocity changes occur in the medium (Zhao & Curtis, ; Zhao et al, ). This is demonstrated in the following section.…”

Section: Resultsmentioning

confidence: 99%

“…However, as we see in Figure , CWI provides a slightly biased estimate of these separations. The relocation method solves for the relative location of a cluster of sources in a probabilistic framework within which it is possible to correct this bias to a significant extent (Robinson et al, ; Zhao & Curtis, ; Zhao et al, ). For one pair of events, according to Bayes' theorem,

P false({\overset{δ}{true}}_{t} false| {\overset{δ}{true}}_{C W I} false) \propto P false({\overset{δ}{true}}_{C W I} false| {\overset{δ}{true}}_{t} false) \times P false({\overset{δ}{true}}_{t} false),

where the posterior probability

P false({\overset{δ}{true}}_{t} false| {\overset{δ}{true}}_{C W I} false)

is the probability of the true separation having value

{\overset{δ}{true}}_{t}

given that the estimated separation from CWI is

{\overset{δ}{true}}_{C W I}

.…”

Section: Resultsmentioning

confidence: 99%

“…However, as we see in Figure 7, CWI provides a slightly biased estimate of these separations. The relocation method solves for the relative location of a cluster of sources in a probabilistic framework within which it is possible to correct this bias to a significant extent (Robinson et al, 2013;Zhao & Curtis, 2019;Zhao et al, 2017). For one pair of events, according to Bayes' theorem,…”

Section: Relocating Relative Source Locations From Intersource Distancementioning

confidence: 99%

“…There have been several field and laboratory applications of CWI to date, including the monitoring of velocity changes in ice sheets (James et al, ; Mordret et al, ), concrete (Larose & Hall, ; Planès & Larose, ), mining environments (Grêt et al, ), and volcanic regions (Sens‐Schönfelder & Wegler, ). CWI has also been used to study earthquake focal mechanisms (Robinson et al, ), earthquake separation distances (Robinson et al, ; Snieder & Vrijlandt, ), and source network locations of induced microseismic events (Zhao & Curtis, ; Zhao et al, ). So far its implications for the interpretation of laboratory rock physics experiments have been comparatively limited.…”

Section: Introductionmentioning

confidence: 99%

“…These codes use a form of CWI that estimates changes relative to a moving‐reference seismogram, which is particularly important for longer deformation experiments in which scattering paths may change significantly, a situation that contravenes the assumptions of standard CWI theory and requires the reference seismogram to be updated periodically. Together with the suite of CWI codes made publicly available by Zhao and Curtis (), this allows all techniques used in this paper to be implemented and reproduced.…”

Section: Introductionmentioning

confidence: 99%

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Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

et al. 2019

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In many geoscientific, material science, and engineering applications it is of importance to estimate a representative bulk seismic velocity of materials or to locate the source of recorded seismic or acoustic waves. Such estimates are necessary in order to interpret industrial seismic and earthquake seismological data, for example, in nondestructive evaluation and monitoring of structural materials, and as an input to rock physics models that predict other parameters of interest. Bulk velocity is commonly estimated in laboratories from the time of flight of the first‐arriving wave between a source and a receiver, assuming a linear raypath. In heterogeneous media, that method provides biased estimates of the bulk velocity, and of derived parameters such as temporal velocity changes or the locations of acoustic emissions. We show that coda wave interferometry (CWI) characterizes changes in the bulk properties of scattering media far more effectively on the scale of laboratory rock samples. Compared to conventional methods, CWI provides significant improvements in both accuracy and precision of estimates of velocity changes, and distances between pairs of acoustic sources, remaining accurate in the presence of background noise, and when source location and velocity perturbations occur simultaneously. CWI also allows 3‐D relative locations of clusters of acoustic emissions to be estimated using only a single sensor. We present a method to use CWI to infer changes in both P and S wave velocities individually. These innovations represent significant improvements in our ability to characterize the evolution of properties of media for a variety of applications.

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Section: Resultsmentioning

confidence: 99%

P false({\overset{δ}{true}}_{t} false| {\overset{δ}{true}}_{C W I} false) \propto P false({\overset{δ}{true}}_{C W I} false| {\overset{δ}{true}}_{t} false) \times P false({\overset{δ}{true}}_{t} false),

where the posterior probability

P false({\overset{δ}{true}}_{t} false| {\overset{δ}{true}}_{C W I} false)

is the probability of the true separation having value

{\overset{δ}{true}}_{t}

given that the estimated separation from CWI is

{\overset{δ}{true}}_{C W I}

.…”

Section: Resultsmentioning

confidence: 99%

Section: Relocating Relative Source Locations From Intersource Distancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

et al. 2019

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Toward Source Region Tomography With Intersource Interferometry: Shear Wave Velocity From 2018 West Bohemia Swarm Earthquakes

Eulenfeld

2020

JGR Solid Earth

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The concept of seismic interferometry embraces the construction of waves traveling between receivers or sources with cross-correlation techniques. In the present study cross correlations of coda waves are used to measure traveltimes of shear waves between earthquake locations for five event clusters of the 2018 West Bohemia earthquake swarm. With the help of a high-quality earthquake catalog, I was able to determine the shear wave velocity in the region of the five clusters separately. The shear wave velocities range between 3.5 and 4.2 km/s. The resolution of this novel method is given by the extent of the clusters and better than for a comparable classical tomography. It is suggested to use the method in a tomographic inversion and map the shear wave velocity in the source region with unprecedented resolution. Furthermore, the influence of focal mechanisms and the attenuation properties on the polarity and location of the maxima in the cross-correlation functions is discussed. The intracluster ratio of P wave to S wave velocity is approximately fixed at 1.68.

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Relative earthquake location procedure for clustered seismicity with a single station

Grigoli

Ellsworth

Zhang

et al. 2020

Geophysical Journal International

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Summary Earthquake location is one of the oldest problems in seismology, yet remains an active research topic. With dense seismic monitoring networks it is possible to obtain reliable locations for microearthquakes; however, in many cases dense networks are lacking, limiting the location accuracy, or preventing location when there are too few observations. For small events in all settings, recording may be sparse and location may be difficult due to low signal-to-noise ratio. In this work we introduce a new, distance-geometry-based method to locate seismicity clusters using only one or two seismic stations. A Distance Geometry Problem determines the location of sets of points based only on the distances between some member pairs. Applied to seismology, our approach allows earthquake location using the inter-event distance between earthquakes pairs, which can be estimated using only one or two seismic stations. We first validate the method with synthetic data that resemble common cluster shapes, and then test the method with two seismic sequences in California: the August 2014 Mw 6.0 Napa earthquake band the July 2019 Mw 6.4 Ridgecrest earthquake sequence. We demonstrate that our approach provides robust and reliable results even for a single station. When using two seismic stations, the results capture the same structures recovered with high resolution Double Difference locations based on multiple stations. The proposed method is particularly useful for poorly monitored areas, where only a limited number of stations are available.

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Relative source location using coda-wave interferometry: Method, code package, and application to mining-induced earthquakes

Cited by 5 publications

References 44 publications

Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

Toward Source Region Tomography With Intersource Interferometry: Shear Wave Velocity From 2018 West Bohemia Swarm Earthquakes

Relative earthquake location procedure for clustered seismicity with a single station

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