A Fast Evaluation of the Seismic Moment Tensor for Induced Seismicity

Trifu, C-I; Angus, D.A.; Shumila, V.

doi:10.1785/0120000034

Cited by 51 publications

(34 citation statements)

References 15 publications

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“…This method relies on calculating the integral of the squared velocity time history (S V2 ) and the squared displacement time history (S D2 ) from P and S waves. Trifu et al (2000) corrected the original equations for S V2 and S D2 , which had an extraneous coefficient of two outside the integral. The correct equations are…”

Section: Kinematic Source Parametersmentioning

confidence: 99%

Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010

Justinic¹,

Stump²,

Hayward³

et al. 2013

Bulletin of the Seismological Society of America

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On 9 June 2009, an M bLg 2.8 earthquake shook Cleburne, Texas, a community not known to have previously experienced earthquakes. Over 50 small earthquakes followed by the end of December 2009. A temporary network of four and then five IRIS-Passcal broadband systems was deployed from June 2009 to June 2010, recording data that were used to locate 38 events with the most confident P-and S-arrival picks. Event locations were distributed along a 2 km long north-northeast trend. The location centroid was at 32.298°N, 97.372°W and at 3.6 km depth. This location is approximately 1.3 km from a saltwater disposal well that began injection in October 2007 and 3.2 km away from a second injection well that was active from September 2005 to late July 2009. Focal mechanisms estimated for the best-recorded events suggest a north-northeast-south-southwest-trending normal fault with a dip of ∼50°and a component of oblique motion (rake of ∼ − 80°). This average solution is generally consistent with the north-northeast-trending extensional faults that are prevalent across parts of Texas, Oklahoma, Louisiana, and Arkansas. Stress drops calculated from P and S spectra for seven different events ranged from 3.9 to 90 bars, with most estimates between 40 and 50 bars, typical values for intraplate earthquakes. Because there were no known previous earthquakes, and the located events were close to the two injection wells and near the injection depth, the possibility exists that earthquakes may be related to fluid injection.Online Material: Tables of absolute and relative earthquake locations and a figure summarizing focal mechanism solutions.

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Section: Kinematic Source Parametersmentioning

confidence: 99%

Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010

Justinic¹,

Stump²,

Hayward³

et al. 2013

Bulletin of the Seismological Society of America

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“…In a previous study of Cotton Valley microseismicity, Rentsch et al (2007) observe a dominant frequency of 100 Hz. It is not uncommon, however, to observe dominant frequencies down to the 10's of Hz (e.g., Teanby et al, 2004) and up to the 100's Hz (e.g., Trifu et al, 2000). Therefore, to capture a realistic range of source frequencies, we simulate three source frequencies at 40 Hz, 150 Hz and 300 Hz.…”

Section: Microseismic Sourcementioning

confidence: 99%

Influence of a velocity model and source frequency on microseismic waveforms: some implications for microseismic locations

Usher

Angus

Verdon

2012

Geophysical Prospecting

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In this paper, we examine the influence of a velocity model and microseismic source frequency on microseismic waveforms and event locations. Finite‐difference waveform synthetics are generated based on the Cotton Valley hydraulic fracture experiment, where we vary the vertical heterogeneity of the velocity models as well as the microseismic source frequencies. We find that differences between plausible velocity models lead to changes in arrival times of approximately 0.0035 seconds for P‐waves and 0.0085 seconds for S‐waves. Based on the average P‐ and S‐wave velocities, the difference in the P‐ and S‐wave traveltimes is equivalent to approximately 20 m in location difference. Significant increases in the waveform coda develop with increasing model heterogeneity and increasing source frequency. The presence of signal noise as well as other sources of error (e.g., uncertainty in geophone location) will likely lead to further increase in uncertainty in location error estimates. Thus we note that location error due to incorrect velocity models cannot be ignored.

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“…If these errors are strongly correlated, they might produce systematic artifacts that could be mistaken for real geophysical phenomena. To date, only a few moment-tensor analyses have included any kind of error analysis (Baker and Young, 1997;Trifu et al, 2000;Šílený et al, 2009;Baig and Urbancic, 2010).…”

Section: Confidence Bounds For Moment Tensorsmentioning

confidence: 99%

Earthquakes and errors: Methods for industrial applications

Foulger

Julian

2011

GEOPHYSICS

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The high accuracies and realistic confidence assessments demanded for seismic monitoring of hydraulic fracturing work require specialist experimental approaches. These include seismic network design based on quantitative modeling, high-quality instrument deployments, and accurate and detailed crustal models. Confidence estimates must take into account uncertainties about crustal structure, which may dominate error budgets. Earthquake size should be expressed in terms of scalar seismic moment or the associated moment magnitude M W , which is related to fundamental physical source processes, and not as traditional earthquake magnitudes. Representing earthquake mechanisms in terms of seismic moment tensors allows for processes such as volume changes and complex types of shearing that are important in hydrocarbon and geothermal reservoirs. Traditional fault-plane solutions are based on simplifying assumptions such as shear slip on a planar faults, and isotropic crustal structures, which may introduce large uncertainties. Quantitative assessment of confidence regions for moment-tensor source mechanisms, a newly emerging field, is important for distinguishing computational artifacts from real physical phenomena. We review methods currently available for realistic error estimation for earthquake locations and moment tensors, with particular emphasis on surface sensor arrays in geothermal areas.

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A Fast Evaluation of the Seismic Moment Tensor for Induced Seismicity

Cited by 51 publications

References 15 publications

Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010

Analysis of the Cleburne, Texas, Earthquake Sequence from June 2009 to June 2010

Influence of a velocity model and source frequency on microseismic waveforms: some implications for microseismic locations

Earthquakes and errors: Methods for industrial applications

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