The SCEC Phase III Strong-Motion Database

Steidl, Jamison H.; Lee, Yajie

doi:10.1785/0120000511

Cited by 18 publications

(23 citation statements)

References 16 publications

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“…crustal.ucsb.edu), and described in detail in Steidl and Lee (2000). The ground-motion parameters used in this study are PGA and 5% damped response spectral acceleration (RSA) at three periods; 0.3, 1.0, and 3.0 sec.…”

Section: Strong-motion Data Setmentioning

confidence: 99%

“…The rockattenuation relation of Sadigh (1993) was used as the rockreference relation. Observed PGA and RSA values are taken from the SCEC, SMDB (Steidl and Lee, 2000). The rock relation of Sadigh et al (1997) is evaluated in , and its bias and standard deviation when applied to the southern California data make it an adequate choice for the reference relation in this study.…”

Section: Strong-motion Data Setmentioning

confidence: 99%

“…The subset of the QTM data set that is classified as Qy, Qo is plotted in Figure 4. Site-class information for each of the stations is contained in Steidl and Lee (2000). Examples of magnitude versus predicted rock PGA and magnitude versus distance for each classification are given in Figures 2-5 of Steidl and Lee (2000).…”

Section: Strong-motion Data Setmentioning

confidence: 99%

“…This parameter is determined from from version 1 of the SCEC 3D velocity model, which is a combination of the work of Magistrale et al (1996) and Graves and Wald (1998). The depth-to-basement parameter is assigned to each of the strong-motion sites within the basin model and is listed in Table 2 of Steidl and Lee (2000).…”

Section: Depth-to-basement Parametermentioning

confidence: 99%

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Site Response in Southern California for Probabilistic Seismic Hazard Analysis

Steidl

2000

Bulletin of the Seismological Society of America

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This study determines site-response factors that can be applied as corrections to a rock-attenuation relationship for use in probabilistic seismic-hazard analysis. The site-response factors are amplitude and site-class dependent. These amplification factors are determined by averaging ratios between observed and predicted ground motions for peak ground acceleration (PGA) and for 5% damped response spectral acceleration at 0.3, 1.0, and 3.0 sec oscillator periods. The observations come from the strong-motion database of the Southern California Earthquake Center (SCEC), and the predictions are based on the Sadigh (1993) rock-attenuation relation. When separated and averaged according to surface geology, significantly different site-response factors are found for Quaternary and Mesozoic units, but a subclassification of Quaternary is generally not justified by the data. The low inputmotion amplification factors are consistent with those obtained from independent aftershock studies at the PGA and 0.3-second period. An observed trend of decreasing Quaternary site amplification with higher input motion is consistent with nonlinear soil behavior; however, the trend exists for Mesozoic sites as well, implying that this may be an artifact of the Sadigh relationship. There is a correlation between larger site-response factors and lower average shear-wave velocity in the upper 30 m for low predicted PGA input motions, with an increase in the correlation with increasing period. The 0.3-sec site response factors for Quaternary data in southern California determined in this study are consistent with 0.3-sec NEHRP site-response correction factors; however, at 1.0-sec period some inconsistencies remain. A trend is also seen with respect to sediment basin depth, where deeper sites have higher average siteresponse factors. These results constitute a customized attenuation relationship for southern California. The implication of these customized attenuation models with respect to probabilistic hazard analysis is examined in Field and Petersen (2000).

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Section: Strong-motion Data Setmentioning

confidence: 99%

Section: Strong-motion Data Setmentioning

confidence: 99%

Section: Strong-motion Data Setmentioning

confidence: 99%

Section: Depth-to-basement Parametermentioning

confidence: 99%

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Site Response in Southern California for Probabilistic Seismic Hazard Analysis

Steidl

2000

Bulletin of the Seismological Society of America

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“…Graphical representation of uncertainty scaling California (latitude range between 32 N and 36 N), for 281 stations in southern California and 28 earthquakes with magnitudes larger than 5.0 determined between 32 N and 36 N. In this database, the 1994 Northridge earthquake is also included (M = 6.7) (Steidl and Lee 2000). There, stations are classified by their surface geology as summarized in Table 2.…”

Section: Expected Value and Standard Deviation For Trapezoidal Fuzzy mentioning

confidence: 99%

Assessment of uncertainties related to seismic hazard using fuzzy analysis

2011

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Seismic hazard analysis in the last few decades has become a very important issue. Recently, new technologies and available data have been improved that have helped many scientists to understand where and why earthquakes happen, the physics of earthquakes, etc. Scientists have begun to understand the role of uncertainty in seismic hazard analysis. However, how to handle existing uncertainty is still a significant problem. The same lack of information causes difficulties in quantifying uncertainty accurately. Usually, attenuation curves are obtained in a statistical manner: regression analysis. Statistical and probabilistic analyses show overlapping results for the site coefficients. This overlapping takes place not only at the border between two neighboring classes but also among more than three classes. Although the analysis starts from classifying sites using geological terms, these site coefficients are not classified at all. In the present study, this problem is solved using fuzzy set theory. Using membership functions, the ambiguities at the border between neighboring classes can be avoided. Fuzzy set theory is performed for southern California in the conventional way. In this study, standard deviations that show variations between each site class obtained by fuzzy set theory and the classical manner are compared. Results of this analysis show that when we have insufficient data for hazard assessment, site classification based on fuzzy set theory shows values of standard deviations less than those obtained using the classical way, which is direct proof of less uncertainty.

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The analysis of Yunnan Dayao basin effect based on microtremor test and numerical simulation

He,

Zhang,

Liu

et al. 2024

Earthquake Engineering and Resilience

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Microtremor tests and finite element numerical simulations were used to analyze the seismic ground motion effects of the Yunnan Dayao sedimentary basin. The results of the microtremor relative to the reference point spectral ratio (HS/HR) method showed that the spectral ratio curves of each observation point in Dayao basin show multipeak characteristics, indicating that the site consists of different soil layers; the predominant frequencies of each observation point mainly are 6~9 Hz in the basin and there are lots of differences in the predominant frequencies of different observation points, which indicate that the site stiffness of each observation point is different; the differences of spectral ratios between the east–west directions (EW) and the north–south directions (NS) reveal the site's anisotropy. The amplification coefficient characteristics of each observation point in the basin obtained by numerical simulation show that the predominant frequency is 6 ~ 9 Hz; the amplification coefficients of each observation point are different; the edge effect and the focusing effect amplify the seismic ground motion in the basin; the different amplification coefficients of the two sub‐basins reflect the significant effect of the basin soil layers' differences on the seismic ground motion, the site is softer and amplification coefficients are larger; the slope degree of basin edges significantly affects the seismic ground motion near the basins edge, the amplification coefficients of the slope steeper and amplification coefficients larger. This study demonstrates that the microtremor test spectral ratio (HS/HR) method has good reliability applied to the analysis of basin effect and combining the finite element numerical simulation method is more effective in revealing the basin effect mechanism.

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The SCEC Phase III Strong-Motion Database

Cited by 18 publications

References 16 publications

Site Response in Southern California for Probabilistic Seismic Hazard Analysis

Site Response in Southern California for Probabilistic Seismic Hazard Analysis

Assessment of uncertainties related to seismic hazard using fuzzy analysis

The analysis of Yunnan Dayao basin effect based on microtremor test and numerical simulation

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