A Modified Ground-Motion Attenuation Relationship for Southern California that Accounts for Detailed Site Classification and a Basin-Depth Effect

2000 ◽  
Vol 90 (6B) ◽  
pp. S209-S221 ◽  
Author(s):  
E. H. Field
Keyword(s):  
Ground Motion ◽  
Southern California ◽  
Site Classification ◽  
Attenuation Relationship ◽  
Depth Effect ◽  
Ground Motion Attenuation

Attenuation and excitation of three-component ground motion in southern California

1999 ◽  
Vol 89 (4) ◽  
pp. 888-902 ◽  
Author(s):  
M. Raoof ◽  
R. B. Herrmann ◽  
L. Malagnini
Keyword(s):  
Ground Motion ◽  
Southern California ◽  
Vertical Component ◽  
Stochastic Simulations ◽  
Geometrical Spreading ◽  
Data Set ◽  
Frequency Dependent ◽  
Ground Motion Attenuation ◽  
Spreading Function ◽  
Velocity Spectra

Abstract Ground motion attenuation with distance and the variation of excitation with magnitude are parameterized using three-component, 0.25 to 5.0-Hz earthquake ground motions recorded in the distance range of 15-500 km for southern California to define a consistent model that describes both peak ground motion and Fourier spectra observations. The data set consists of 820 three-component TERRAscope recordings from 140 earthquakes, recorded at 17 stations, with moment magnitudes between 3.1 and 6.7. Regression analysis uses a simple model to relate the logarithm of measured ground motion to excitation, site, and propagation effects. The peak motions are Fourier velocity spectra and peak velocities in selected narrow bandpass-filtered frequency ranges. Regression results for Fourier amplitude spectra and peak velocities are used to define a piecewise continuous geometrical spreading function, frequency dependent Q(f), and a distance dependent duration that can be used with random vibration theory (RVT) or stochastic simulations to predict other characteristics of the ground motion. The duration results indicate that both the variation of the duration data with distance and its scattering decrease with increasing frequency. The ratio of horizontal to vertical component site terms is about √2 for all frequencies. However, this ratio is near unity for rock sites and is larger for soil sites. Simple modeling indicates that the Fourier velocity spectra are best fit by bilinear geometrical spreading of r−1 for r < 40 km and r−1/2 for r > 40 km. The frequency-dependent quality factor is Q(f) = 180f0.45 for each of the three components and also for the combined three-component data sets. The T5%-75% duration window provides good agreement between observed and RVT predicted peak values.

scholarly journals Multisource Ground Motion Attenuation Relationship Model for the Vertical Component of the Wenchuan Earthquake on May 12, 2008

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ping Liu ◽  
Tongjie Ren ◽  
Hai Wang ◽  
Chunfeng Li ◽  
Baoqiang Wang ◽  
...  
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Response Spectrum ◽  
Site Effect ◽  
Source Model ◽  
Attenuation Relationship ◽  
Ground Motion Attenuation ◽  
Vertical Ground Motion ◽  
The Wenchuan Earthquake ◽  
Vertical Ground

In order to extend the multisource model to vertical ground motion, we fit the vertical ground motion attenuation relationship of the Wenchuan earthquake. Different from traditional attenuation relationship forms, we propose a simplified ground motion attenuation function including site effect via a flag related to VS30. The regression results show that it has site effect on the vertical ground motion of the Wenchuan earthquake and gradually weakens with the increase in periods. According to residuals analysis, the hanging-wall effect on vertical ground motion is strong for the Wenchuan earthquake, especially in short periods. The result analysis indicates that the shape of the vertical response spectrum based on regression is different from that of the horizontal component and complies with the recommended design vertical response spectrum of FEMA P-1050. V/H (vertical-to-horizontal ratios), as a main way to estimate vertical ground motion, cannot be simply fixed as 2/3. Therefore, site location, site condition, and frequency spectrum have to be considered comprehensively. The regression accuracy of the vertical ground motion of the multisource model is slightly higher than that of the point-source model and lower than that of the finite fault source model. It is expected that this model will serve as an alternative for source-to-site distance when multiple asperities are to be modeled in the absence of the detail fault model to get a general scenario of the future ground motions.

A Monte Carlo approach to seismic hazard analysis

1999 ◽  
Vol 89 (4) ◽  
pp. 854-866 ◽  
Author(s):  
John E. Ebel ◽  
Alan L. Kafka
Keyword(s):  
Monte Carlo ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Epicentral Distance ◽  
Ground Motions ◽  
Source Parameters ◽  
Parametric Models ◽  
Earthquake Catalog ◽  
Attenuation Relations ◽  
Ground Motion Attenuation

Abstract We have developed a Monte Carlo methodology for the estimation of seismic hazard at a site or across an area. This method uses a multitudinous resampling of an earthquake catalog, perhaps supplemented by parametric models, to construct synthetic earthquake catalogs and then to find earthquake ground motions from which the hazard values are found. Large earthquakes extrapolated from a Gutenberg-Richter recurrence relation and characteristic earthquakes can be included in the analysis. For the ground motion attenuation with distance, the method can use either a set of observed ground motion observations from which estimates are randomly selected, a table of ground motion values as a function of epicentral distance and magnitude, or a parametric ground motion attenuation relation. The method has been tested for sites in New England using an earthquake catalog for the northeastern United States and southeastern Canada, and it yields reasonable ground motions at standard seismic hazard values. This is true both when published ground motion attenuation relations and when a dataset of observed peak acceleration observations are used to compute the ground motion attenuation with distance. The hazard values depend to some extent on the duration of the synthetic catalog and the specific ground motion attenuation used, and the uncertainty in the ground motions increases with decreasing hazard probability. The program gives peak accelerations that are comparable to those of the 1996 U.S. national seismic hazard maps. The method can be adapted to compute seismic hazard for cases where there are temporal or spatial variations in earthquake occurrence rates or source parameters.

Sign in / Sign up

Export Citation Format

Share Document