Attenuation of high‐frequency shear waves in the crust: Measurements from New York State, South Africa, and southern California

Frankel, Arthur; McGarr, A.; Bicknell, J.; Mori, Jim; Seeber, Leonardo; Cranswick, Edward

doi:10.1029/jb095ib11p17441

Cited by 176 publications

(117 citation statements)

References 23 publications

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“…Variations in regional attenuation (1/Q) can facilitate structure and tectonic interpretation (e.g., FRANKEL, 1990). Local and regional distance attenuation of seismic phases is important in earthquake hazard prediction.…”

Section: Introductionmentioning

confidence: 99%

Attenuation Tomography of the Yellow Sea/Korean Peninsula from Coda-source normalized and direct Lg Amplitudes

Ford

Phillips

Walter

et al. 2009

Pure Appl. Geophys.

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Abstract-We invert for regional attenuation of the crustal phase Lg in the Yellow Sea/Korean Peninsula (YSKP) using three different amplitude attenuation tomography methods. The first method solves for source, site, and path attenuation. The second method uses a scaling relationship to set the initial source amplitude and interpret the source term after inversion. The third method implements a coda-derived source spectral correction. By comparing methods with slightly different assumptions we are able to make a more realistic assessment of the uncertainties in the resulting attenuation maps than is obtainable through formal error analysis alone. We compare the site, source and path-terms produced by each method and comment on attenuation, which correlates well with tectonic and topographic features in the region. Source terms correlate well with each other and with magnitude. Site terms are similar except for two stations that are located in a region that has the greatest difference in path term, which demonstrates the site/path trade-off. Another region of path term difference has the fewest crossing paths, where the tomography method employing the coda-derived spectral correction may perform more accurately since it is not as susceptible to the source/ path trade-off. The Bohai Bay basin, an area of extension, is a region of high attenuation, and regions of low attenuation occur along topographic highs located in the Da-xin-an-ling and Changbai Mountains and Mount Taishan.

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Section: Introductionmentioning

confidence: 99%

Attenuation Tomography of the Yellow Sea/Korean Peninsula from Coda-source normalized and direct Lg Amplitudes

Ford

Phillips

Walter

et al. 2009

Pure Appl. Geophys.

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“…Data were excluded if either A Lg or C had a SNR less than two, where noise is measured as the maximum amplitude in a window the same length as A Lg prior to the event. This method is similar to that of Chung and Lee (2003), whereas Frankel (1990) used a weighted average of the smoothed coda to measure C. We calculate (4) with all records at a given station, where the slope is calculated with an iteratively weighted least-squares method that reduces the influence of outlier observations. An example for station PKD is given in Figure 2.…”

Section: Coda Normalization (Cn)mentioning

confidence: 99%

“…It can help with structure and tectonic interpretation (e.g., (Aleqabi and Wysession, 2006;Benz et al, 1997;Frankel, 1990), with seismic hazard mitigation in terms of better understanding strong ground motion attenuation (e.g., Anderson et al 1996;Hanks and Johnston, 1992), as well as in the simulation of strong ground motions (e.g., Graves and Day, 2003;Olson and Anderson, 1988), and in nuclear explosion monitoring (e.g., Baker et al, 2004;Mayeda et al, 2003;Taylor et al, 2002). A well-known issue with reported values of Q for regional phases in the literature is that they can vary greatly in the same region depending upon the methodology used to derive them.…”

Section: Introductionmentioning

confidence: 99%

Regional Attenuation in Northern California: A Comparison of Five 1D Q Methods

Ford

Dreger

Mayeda

et al. 2008

Bulletin of the Seismological Society of America

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The determination of regional attenuation Q -1 can depend upon the analysis method employed. The discrepancies between methods are due to differing parameterizations (e.g., geometrical spreading rates), employed datasets (e.g., choice of path lengths and sources), and the methodologies themselves (e.g., measurement in the frequency or time domain). Here we apply five different attenuation methodologies to a Northern California dataset. The methods are: (1) coda normalization (CN), (2) two-station (TS), (3) reverse two-station (RTS), (4) sourcepair/receiver-pair (SPRP), and (5) coda-source normalization (CS). The methods are used to measure Q of the regional phase, Lg (Q Lg ), and its power-law dependence on frequency of the form Q 0 f η with controlled parameterization in the well-studied region of Northern California using a high-quality dataset from the Berkeley Digital Seismic Network. We investigate the difference in power-law Q calculated among the methods by focusing on the San Francisco Bay Area, where knowledge of attenuation is an important part of seismic hazard mitigation. This approximately homogeneous subset of our data lies in a small region along the Franciscan block. All methods return similar power-law parameters, though the range of the joint 95% confidence regions is large (Q 0 = 85 ± 40; η = 0.65 ± 0.35). The RTS and TS methods differ the most from the other methods and from each other. This may be due to the removal of the site term in the RTS method, which is shown to be significant in the San Francisco Bay Area. In order to completely understand the range of power-law Q in a region, it is advisable to use several methods to calculate the model. We also test the sensitivity of each method to changes in geometrical spreading, Lg frequency bandwidth, the distance range of data, and the Lg measurement window. For a given method, there are significant differences in the power-law parameters, Q 0 and η, due to perturbations in the parameterization when evaluated using a conservative pairwise comparison. The CN method is affected most by changes in the distance range, which is most probably due to its fixed coda measurement window. Since, the CS method is best used to calculate the total path attenuation, it is very sensitive to the geometrical spreading assumption. The TS method is most sensitive to the frequency bandwidth, which may be due to its incomplete extraction of the site term. The RTS method is insensitive to parameterization choice, whereas the SPRP method as implemented here in the time-domain for a single path has great error in the power-law model parameters and η is strongly affected by changes in the method parameterization. When presenting results for a given method it is best to calculate Q 0 f η for multiple parameterizations using some a priori distribution.

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“…(Aki, 1980;Frankel et al, 1990) can be used to eliminate the source and site terms by taking the ratio of the peak amplitude carried by S or L g waves in filtered time histories to the root-mean-square (rms) amplitude of the stable seismic coda. The coda-normalized amplitude can be written in the form:…”

Section: Procedures To Derive Attenuation Relationshipmentioning

confidence: 99%

Peak ground motion predictions with empirical site factors using Taiwan Strong Motion Network recordings

Chung

2013

Earth Planet Sp

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A stochastic method called the random vibration theory (Boore, 1983) has been used to estimate the peak ground motions caused by shallow moderate-to-large earthquakes in the Taiwan area. Adopting Brune's ω-square source spectrum, attenuation models for PGA and PGV were derived from path-dependent parameters which were empirically modeled from about one thousand accelerograms recorded at reference sites mostly located in a mountain area and which have been recognized as rock sites without soil amplification. Consequently, the predicted horizontal peak ground motions at the reference sites, are generally comparable to these observed. A total number of 11,915 accelerograms recorded from 735 free-field stations of the Taiwan Strong Motion Network (TSMN) were used to estimate the site factors by taking the motions from the predictive models as references. Results from soil sites reveal site amplification factors of approximately 2.0 ∼ 3.5 for PGA and about 1.3 ∼ 2.6 for PGV. Finally, as a result of amplitude corrections with those empirical site factors, about 75% of analyzed earthquakes are well constrained in ground motion predictions, having average misfits ranging from 0.30 to 0.50. In addition, two simple indices, R 0.57 and R 0.38 , are proposed in this study to evaluate the validity of intensity map prediction for public information reports. The average percentages of qualified stations for peak acceleration residuals less than R 0.57 and R 0.38 can reach 75% and 54%, respectively, for most earthquakes. Such a performance would be good enough to produce a faithful intensity map for a moderate scenario event in the Taiwan region.

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Attenuation of high‐frequency shear waves in the crust: Measurements from New York State, South Africa, and southern California

Cited by 176 publications

References 23 publications

Attenuation Tomography of the Yellow Sea/Korean Peninsula from Coda-source normalized and direct Lg Amplitudes

Attenuation Tomography of the Yellow Sea/Korean Peninsula from Coda-source normalized and direct Lg Amplitudes

Regional Attenuation in Northern California: A Comparison of Five 1D Q Methods

Peak ground motion predictions with empirical site factors using Taiwan Strong Motion Network recordings

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