Waveform inversion for microseismic source parameters: Synthetic and field-data applications

AbstractThis study comprehensively investigates the source mechanisms associated with the mainshock and aftershocks of the Mw = 6.3 Yogyakarta earthquake which occurred on May 27, 2006. The process involved using moment tensor inversion to determine the fault plane parameters and joint inversion which were further applied to understand the spatial and temporal slip distributions during the earthquake. Moreover, coseismal slip distribution was overlaid with the relocated aftershock distribution to determine the stress field variations around the tectonic area. Meanwhile, the moment tensor inversion made use of near-field data and its Green’s function was calculated using the extended reflectivity method while the joint inversion used near-field and teleseismic body wave data which were computed using the Kikuchi and Kanamori methods. These data were filtered through a trial-and-error method using a bandpass filter with frequency pairs and velocity models from several previous studies. Furthermore, the Akaike Bayesian Information Criterion (ABIC) method was applied to obtain more stable inversion results and different fault types were discovered. Strike–slip and dip-normal were recorded for the mainshock and similar types were recorded for the 8th aftershock while the 9th and 16th June were strike slips. However, the fault slip distribution from the joint inversion showed two asperities. The maximum slip was 0.78 m with the first asperity observed at 10 km south/north of the mainshock hypocenter. The source parameters discovered include total seismic moment M0 = 0.4311E + 19 (Nm) or Mw = 6.4 with a depth of 12 km and a duration of 28 s. The slip distribution overlaid with the aftershock distribution showed the tendency of the aftershock to occur around the asperities zone while a normal oblique focus mechanism was found using the joint inversion.

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Target-oriented elastic full-waveform inversion: Deep-water ocean-bottom-node field-data application

10.1190/segam2021-3580825.1 ◽

2021 ◽

Author(s):

Ettore Biondi ◽

Guillaume Barnier ◽

Biondo Biondi ◽

Robert Clapp

Keyword(s):

Deep Water ◽

Field Data ◽

Waveform Inversion ◽

Full Waveform Inversion ◽

Ocean Bottom ◽

Full Waveform ◽

Data Application

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Normalized nonzero-lag crosscorrelation elastic full-waveform inversion

Geophysics ◽

10.1190/geo2018-0082.1 ◽

2019 ◽

Vol 84 (1) ◽

pp. R1-R10 ◽

Cited By ~ 11

Author(s):

Zhendong Zhang ◽

Tariq Alkhalifah ◽

Zedong Wu ◽

Yike Liu ◽

Bin He ◽

...

Keyword(s):

Field Data ◽

Extreme Values ◽

Time Lag ◽

Waveform Inversion ◽

Optimal Time ◽

Full Waveform Inversion ◽

Data Set ◽

Velocity Models ◽

Full Waveform ◽

The Earth

Full-waveform inversion (FWI) is an attractive technique due to its ability to build high-resolution velocity models. Conventional amplitude-matching FWI approaches remain challenging because the simplified computational physics used does not fully represent all wave phenomena in the earth. Because the earth is attenuating, a sample-by-sample fitting of the amplitude may not be feasible in practice. We have developed a normalized nonzero-lag crosscorrelataion-based elastic FWI algorithm to maximize the similarity of the calculated and observed data. We use the first-order elastic-wave equation to simulate the propagation of seismic waves in the earth. Our proposed objective function emphasizes the matching of the phases of the events in the calculated and observed data, and thus, it is more immune to inaccuracies in the initial model and the difference between the true and modeled physics. The normalization term can compensate the energy loss in the far offsets because of geometric spreading and avoid a bias in estimation toward extreme values in the observed data. We develop a polynomial-type weighting function and evaluate an approach to determine the optimal time lag. We use a synthetic elastic Marmousi model and the BigSky field data set to verify the effectiveness of the proposed method. To suppress the short-wavelength artifacts in the estimated S-wave velocity and noise in the field data, we apply a Laplacian regularization and a total variation constraint on the synthetic and field data examples, respectively.

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2D Laplace-Domain Waveform Inversion of Field Data Using a Power Objective Function

Pure and Applied Geophysics ◽

10.1007/s00024-013-0651-4 ◽

2013 ◽

Vol 170 (12) ◽

pp. 2075-2085 ◽

Cited By ~ 7

Author(s):

Eunjin Park ◽

Wansoo Ha ◽

Wookeen Chung ◽

Changsoo Shin ◽

Dong-Joo Min

Keyword(s):

Objective Function ◽

Field Data ◽

Waveform Inversion ◽

Laplace Domain

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Laplace-domain full-waveform inversion of seismic data lacking low-frequency information

Geophysics ◽

10.1190/geo2011-0411.1 ◽

2012 ◽

Vol 77 (5) ◽

pp. R199-R206 ◽

Cited By ~ 31

Author(s):

Wansoo Ha ◽

Changsoo Shin

Keyword(s):

Seismic Data ◽

Field Data ◽

Waveform Inversion ◽

Low Frequency ◽

Single Frequency ◽

Frequency Content ◽

Laplace Domain ◽

Frequency Information ◽

Velocity Models ◽

Gaussian Source

The lack of the low-frequency information in field data prohibits the time- or frequency-domain waveform inversions from recovering large-scale background velocity models. On the other hand, Laplace-domain waveform inversion is less sensitive to the lack of the low frequencies than conventional inversions. In theory, frequency filtering of the seismic signal in the time domain is equivalent to a constant multiplication of the wavefield in the Laplace domain. Because the constant can be retrieved using the source estimation process, the frequency content of the seismic data does not affect the gradient direction of the Laplace-domain waveform inversion. We obtained inversion results of the frequency-filtered field data acquired in the Gulf of Mexico and two synthetic data sets obtained using a first-derivative Gaussian source wavelet and a single-frequency causal sine function. They demonstrated that Laplace-domain inversion yielded consistent results regardless of the frequency content within the seismic data.

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Source characteristics of earthquakes along the southern San Jacinto and Imperial fault zones (1937 to 1954)

Bulletin of the Seismological Society of America ◽

10.1785/bssa0800051099 ◽

1990 ◽

Vol 80 (5) ◽

pp. 1099-1117 ◽

Cited By ~ 1

Author(s):

Diane I. Doser

Keyword(s):

Heat Flow ◽

Source Parameters ◽

Waveform Inversion ◽

High Heat ◽

Seismogenic Zone ◽

Data Sets ◽

Imperial Valley ◽

Rupture Length ◽

Lower Heat ◽

Inversion Techniques

Abstract Body waveform inversion techniques are used to study the source parameters of four earthquakes occurring between 1937 and 1954 along the southern San Jacinto and Imperial faults (1937 Buck Ridge, 1940 Imperial Valley, 1942 Borrego Mountain, and 1954 Salada Wash events). All earthquakes had simple rupture histories with the exception of the 1940 Imperial Valley main shock, which consisted of at least four subevents whose relative locations indicate unilateral rupture toward the southeast. Earthquakes in regions of high heat flow (>80 mW/m2) had focal depths near the base of the seismogenic zone (8 to 10 km). The 1937 Buck Ridge earthquake, located in a region of lower heat flow, however, appears to have occurred at a shallow (3 ± 2 km) depth. The location, mechanism, and aftershock distribution for the 1942 Borrego Mountain earthquake suggest it could have occurred along the Split Mountain fault, a recently identified northeast-trending cross fault located between the Elsinore and Coyote Creek faults or along an unnamed fault that parallels the trend of the Coyote Creek fault. Moment and rupture length estimates obtained from this study agree well with estimates obtained in previous studies that used different data sets.

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