scholarly journals Estimation of strong ground motions in Mexico City expected for large earthquakes in the Guerrero seismic gap

1993 ◽  
Vol 83 (3) ◽  
pp. 811-829 ◽  
Author(s):  
Hiroo Kanamori ◽  
Paul C. Jennings ◽  
Shri Krishna Singh ◽  
Luciana Astiz
Keyword(s):  
Ground Motion ◽  
Mexico City ◽  
Response Spectrum ◽  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Simulation Method ◽  
Propagation Path ◽  
Seismic Gap ◽  
Large Earthquakes

Abstract We performed simulations of ground motions in Mexico City expected for large earthquakes in the Guerrero seismic gap in Mexico. The simulation method uses as empirical Green's functions the accelerograms recorded in Mexico City during four small to moderate earthquakes (8 Feb. 1988, Ms = 5.8; 25 April 1989, Mw = 6.9; 11 May 1990, Mw = 5.5; and 31 May 1990, Mw = 6.0) in the Guerrero gap. Because these events occurred in the Guerrero gap, and have typical thrust mechanisms, the propagation path and site effects can be accurately included in our simulation. Fault rupture patterns derived from the 1985 Michoacan earthquake and source scaling relations appropriate for Mexican subduction zone earthquakes are used. If the Guerrero event is similar to the 1985 Michoacan event, the resulting response spectrum in Mexico City will be approximately twice as large as that of the 1985 Michoacan earthquake at periods longer than 2 sec. At periods shorter than 2 sec, the amplitude will be 2 to 3 times larger than that for the Michoacan earthquake. If the events in the Guerrero seismic gap occur as a sequence of magnitude 7.5 to 7.8 events, as they did in the previous sequence around the turn of the century, the strong motion in Mexico City is estimated to be about half that experienced during the 1985 Michoacan earthquake at periods longer than 2 sec. However, several factors affect this estimate. The magnitude of the possible events has a significant range and, if a rupture sequence is such that it enhances ground-motion amplitude with constructive interference, as occurred during the second half of the Michoacan sequence, some components of the ground motion could be amplified by a factor of 2 to 3. To aid in the interpretation of the simulated motion for purposes of design or hazard assessment, design spectra for the CDAO site in Mexico City are derived from the response spectra of the simulated ground motions.

scholarly journals Simulation of response spectrum-compatible ground motions using wavelet-based multi-resolution analysis

2021 ◽  
pp. 002029402110130
Author(s):  
Guan Chen ◽  
Zhiren Zhu ◽  
Jun Hu
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Ground Motions ◽  
Power Spectra ◽  
Simulation Method ◽  
Eurocode 8 ◽  
Effective Response ◽  
Multi Resolution Analysis ◽  
Resolution Analysis ◽  
Simulated Ground Motions

This study proposed a simple and effective response spectrum-compatible ground motions simulation method to mitigate the scarcity of ground motions on seismic hazard analysis base on wavelet-based multi-resolution analysis. The feasibility of the proposed method is illustrated with two recorded ground motions in El Mayor-Cucapah earthquake. The results show that the proposed method enriches the ground motions exponentially. The simulated ground motions agree well with the attenuation characteristics of seismic ground motion without modulating process. Moreover, the pseudo-acceleration response spectrum error between the recorded ground motion and the average of the simulated ground motions is 5.2%, which fulfills the requirement prescribed in Eurocode 8 for artificially simulated ground motions. Besides, the cumulative power spectra between the simulated and recorded ground motions agree well on both high- and low-frequency regions. Therefore, the proposed method offers a feasible alternative in enriching response spectrum-compatible ground motions, especially on the regions with insufficient ground motions.

Spatial Variability of Source and Attenuation Characteristics in Large Ground-Motion Datasets

2020 ◽  
Author(s):  
Sreeram Reddy Kotha ◽  
Graeme Weatherill ◽  
Dino Bindi ◽  
Fabrice Cotton
Keyword(s):  
Spatial Variability ◽  
Ground Motion ◽  
Ground Motions ◽  
Low Frequency ◽  
Strong Motion ◽  
Response Spectra ◽  
Large Datasets ◽  
Earthquake Scenarios ◽  
Crustal Earthquakes ◽  
Geographical Regions

<p>Ground-Motion Models (GMMs) characterize the random distributions of ground-motions for a combination of earthquake source, wave travel-path, and the effected site’s geological properties. Typically, GMMs are regressed over a compendium of strong ground-motion recordings collected from several earthquakes recorded at multiple sites scattered across a variety of geographical regions. The necessity of compiling such large datasets is to expand the range of magnitude, distance, and site-types; in order to regress a GMM capable of predicting realistic ground-motions for rare earthquake scenarios, e.g. large magnitudes at short distances from a reference rock site. The European Strong-Motion (ESM) dataset is one such compendium of observations from a few hundred shallow crustal earthquakes recorded at a several hundred seismic stations in Europe and Middle-East.</p><p>We developed new GMMs from the ESM dataset, capable of predicting both the response spectra and Fourier spectra in a broadband of periods and frequencies, respectively. However, given the clear tectonic and geological diversity of the data, possible regional and site-specific differences in observed ground-motions needed to be quantified; whilst also considering the possible contamination of data from outliers. Quantified regional differences indicate that high-frequency ground-motions attenuate faster with distance in Italy compared to the rest of Europe, as well as systematically weaker ground-motions from central Italian earthquakes. In addition, residual analyses evidence anisotropic attenuation of low frequency ground-motions, imitating the pattern of shear-wave energy radiation. With increasing spatial variability of ground-motion data, the GMM prediction variability apparently increases. Hence, robust mixed-effects regressions and residual analyses are employed to relax the ergodic assumption.</p><p>Large datasets, such as the ESM, NGA-West2, and from KiK-Net, provide ample opportunity to identify and evaluate the previously hypothesized event-to-event, region-to-region, and site-to-site differences in ground-motions. With the appropriate statistical methods, these variabilities can be quantified and applied in seismic hazard and risk predictions. We intend to present the new GMMs: their development, performance and applicability, prospective improvements and research needs.</p>

scholarly journals Fully Nonstationary Spatially Variable Ground Motion Simulations Based on a Time-Varying Power Spectrum Model

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Huiguo Chen ◽  
Yingmin Li ◽  
Junru Ren
Keyword(s):  
Power Spectrum ◽  
Ground Motion ◽  
Response Spectrum ◽  
Power Spectra ◽  
Response Spectra ◽  
Simulation Method ◽  
Time Varying ◽  
Time Frequency ◽  
Response Characteristics ◽  
Spectrum Model

By analyzing the evolutionary spectrum method for multivariate nonstationary stochastic processes, a simulation method for fully nonstationary spatially variable ground motion is proposed based on the Kameda time-varying power spectrum model. This method can properly simulate nonstationary spatially variable ground motion based on a target response spectrum. Two numerical examples, in which the Kameda time-varying power spectra are calculated for different conditions, are presented to demonstrate the capabilities of the proposed method. In the first example, the nonstationary spatially variable ground motion that satisfies the time-frequency characteristics and response characteristics of the original ground motion is simulated by identifying the parameters of the given time-varying power spectrum. In the second example, the ground motion that satisfies the design response spectra is simulated by defining the parameters of the time-varying power spectrum directly. The results demonstrate that the method can effectively simulate nonstationary spatially variable ground motion, which implies that the proposed method can be used in engineering applications.

Bi-Directional Pseudo-Acceleration Response Spectra

2016 ◽  
Vol 10 (04) ◽  
pp. 1650007
Author(s):  
Anat Ruangrassamee ◽  
Chitti Palasri ◽  
Panitan Lukkunaprasit
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Acceleration Response ◽  
Acceleration Response Spectra ◽  
Acceleration Response Spectrum ◽  
Two Degree Of Freedom ◽  
Ratio Response

In seismic design, excitations are usually considered separately in two perpendicular directions of structures. In fact, the two components of ground motions occur simultaneously. This paper clarifies the effects of bi-directional excitations on structures and proposes the response spectra called “bi-directional pseudo-acceleration response spectra”. A simplified analytical model of a two-degree-of-freedom system was employed. The effect of directivity of ground motions was taken into account by applying strong motion records in all directions. The analytical results were presented in the form of the acceleration ratio response spectrum defined as the bi-directional pseudo-acceleration response spectrum normalized by a pseudo-acceleration response spectrum.

scholarly journals Frequency-dependent site factors for the Icelandic strong-motion array from a Bayesian hierarchical model of the spatial distribution of spectral accelerations

2021 ◽  
pp. 875529302110369
Author(s):  
Sahar Rahpeyma ◽  
Benedikt Halldorsson ◽  
Birgir Hrafnkelsson ◽  
Sigurjón Jónsson
Keyword(s):  
Ground Motion ◽  
Hierarchical Model ◽  
Response Spectrum ◽  
Ground Motions ◽  
Strong Motion ◽  
Bayesian Hierarchical Model ◽  
Site Factors ◽  
Ground Acceleration ◽  
Small Aperture ◽  
Bayesian Hierarchical

The earthquake ground motions of over 1700 earthquakes recorded on a small-aperture strong-motion array in south Iceland (ICEARRAY I) that is situated on a relatively uniform site condition characterized as rock, exhibit a statistically significant spatial variation of ground-motion amplitudes across the array. Both earthquake and microseismic horizontal-to-vertical spectral ratios (HVSR) have been shown to exhibit distinct and in some cases, bimodal peaks in amplification, indicating site resonance at periods of 0.1–0.3 s, a phenomenon that has been attributed to a surface layer of lava rock lying above a sedimentary layer, a structure that is then repeated with depth under the array. In this study, we implement a Bayesian hierarchical model (BHM) of the seismic ground motions that partitions the model residuals into earthquake event term, station term, and event–station term. We analyzed and compared peak ground acceleration (PGA) with the 5% damped pseudo-acceleration response spectrum (PSA) at oscillator periods of T = 0.05–1.0 s. The results show that the event terms, dominate the total variability of the ground-motion amplitudes over the array. However, the station terms are shown to increase in the period range of 0.1–0.3 s on most stations and to different extents, leading to an increase in the overall variability of ground motions at those periods, captured by a larger inter-station standard deviation. As the station terms are a measure of how much the ground motions at those stations deviate from the array average, they act as proxies for localized site effects and amplification factors. These results, improve our understanding of the key factors that affect the variation of seismic ground motions across the relatively small area of ICEARRAY I. This approach can help to improve the accuracy of earthquake hazard assessments on local scales, which in turn could contribute to more refined seismic risk assessments and engineering decision-making.

scholarly journals A Computationally Efficient Ground-Motion Selection Algorithm for Matching a Target Response Spectrum Mean and Variance

2011 ◽  
Vol 27 (3) ◽  
pp. 797-815 ◽  
Author(s):  
Nirmal Jayaram ◽  
Ting Lin ◽  
Jack W. Baker
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Selection Algorithm ◽  
Target Response ◽  
Computationally Efficient ◽  
Mean And Variance ◽  
The Impact

Dynamic structural analysis often requires the selection of input ground motions with a target mean response spectrum. The variance of the target response spectrum is usually ignored or accounted for in an ad hoc manner, which can bias the structural response estimates. This manuscript proposes a computationally efficient and theoretically consistent algorithm to select ground motions that match the target response spectrum mean and variance. The selection algorithm probabilistically generates multiple response spectra from a target distribution, and then selects recorded ground motions whose response spectra individually match the simulated response spectra. A greedy optimization technique further improves the match between the target and the sample means and variances. The proposed algorithm is used to select ground motions for the analysis of sample structures in order to assess the impact of considering ground-motion variance on the structural response estimates. The implications for code-based design and performance-based earthquake engineering are discussed.

The SMART I Accelerograph Array (1980-1987): A Review

1987 ◽  
Vol 3 (2) ◽  
pp. 263-287 ◽  
Author(s):  
N. A. Abrahamson ◽  
B. A. Bolt ◽  
R. B. Darragh ◽  
J. Penzien ◽  
Y. B. Tsai
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Near Field ◽  
Strong Motion ◽  
Response Spectra ◽  
Transform Faults ◽  
Engineering Research ◽  
Motion Data ◽  
Time Histories

SMART 1 is the first large digital array of strong-motion seismographs specially designed for engineering and seismological studies of the generation and near-field properties of earthquakes. Since the array began operation in September 1980, it has recorded over 3000 accelerogram traces from 48 earthquakes ranging in local magnitude ( ML) from 3.6 to 7.0. Peak ground accelerations have been recorded up to 0.33g and 0.34g on the horizontal and vertical components, respectively. Epicentral distances have ranged from 3 km 200 km from the array center, and focal depths have ranged from shallow to 100 km. The recorded earthquakes had both reverse and strike-slip focal mechanisms associated with the subduction zone and transform faults. These high quality, digital, ground motions provide a varied resource for earthquake engineering research. Earthquake engineering studies of the SMART 1 ground motion data have led to advances in knowledge in several cases: for example, on frequency-dependent incoherency of free-surface ground motions over short distances, on response of linear systems to multiple support excitations, on attenuation of peak ground-motion parameters and response spectra, on site torsion and phasing effects, and on the identification of wave types. Accelerograms from individual strong-motion seismographs do not, in general, provide such information. This review describes the SMART 1 array and the recorded earthquakes with special engineering applications. Also, it tabulates the unfiltered peak array accelerations, displays some of the recorded ground motion time histories, and summarizes the main engineering research that has made use of SMART 1 data.

Strong-Motion Records for Site-Specific Analysis

2003 ◽  
Vol 19 (3) ◽  
pp. 557-578 ◽  
Author(s):  
Praveen K. Malhotra
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Response Spectrum ◽  
Strong Motion ◽  
Response Spectra ◽  
Seismic Events ◽  
Site Specific ◽  
Strong Motion Records ◽  
Specific Analysis ◽  
Selection Of

A procedure is presented to select and scale strong-motion records for site-specific analysis. The procedure matches records’ smooth response spectra with the site response spectrum by scaling of the acceleration histories. The parameters defining the smooth spectrum of various records are computed and tabulated to allow easy selection of records. Hazard de-aggregation is used to identify closer and distant seismic events, which are simulated by the scaled ground motion histories. The procedure can also be used to obtain ground motion pairs in orthogonal directions for multidimensional dynamic response analyses.

An Empirical Relationship between Fourier and Response Spectra Using Spectrum-Compatible Times Series

2017 ◽  
Vol 33 (1) ◽  
pp. 179-199 ◽  
Author(s):  
Luis A. Montejo ◽  
Aidcer L. Vidot-Vega
Keyword(s):  
Time Series ◽  
Earthquake Engineering ◽  
Response Spectrum ◽  
Ground Motions ◽  
Strong Dependence ◽  
Empirical Relationship ◽  
Amplitude Spectrum ◽  
Strong Motion ◽  
Response Spectra ◽  
Elastic Response

The Fourier amplitude spectrum (FAS) is widely used in seismology and earthquake engineering as it provides valuable information regarding frequency dependent amplitude of the ground motion. However, for structural design and assessment, the preferred representation of seismic hazard continues to be based on the elastic response spectrum. Therefore, conversions between these spectra are often required. In this article, the connection between FAS and the 5% damping pseudo-acceleration response spectrum (5% PSA) is explored using large data sets of spectrum-compatible time series generated from white noise. The strong dependence of the relation between FAS and 5% PSA with strong motion duration is evidenced and a duration dependent empirical relationship between the both spectra is developed. The equation is validated using recorded ground motions and spectrum-compatible time series generated from the modification of these ground motions. The equation allows simpler one-step conversions when compared to iterative approaches based on RVT theory or time-consuming methodologies that require the generation of spectrum-compatible time series.

A subset of CyberShake ground-motion time series for response-history analysis

2021 ◽  
pp. 875529302098197
Author(s):  
Jack W Baker ◽  
Sanaz Rezaeian ◽  
Christine A Goulet ◽  
Nicolas Luco ◽  
Ganyu Teng
Keyword(s):  
Time Series ◽  
Los Angeles ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Motion Time ◽  
History Analysis ◽  
Response History Analysis ◽  
Simulated Ground Motions

This manuscript describes a subset of CyberShake numerically simulated ground motions that were selected and vetted for use in engineering response-history analyses. Ground motions were selected that have seismological properties and response spectra representative of conditions in the Los Angeles area, based on disaggregation of seismic hazard. Ground motions were selected from millions of available time series and were reviewed to confirm their suitability for response-history analysis. The processes used to select the time series, the characteristics of the resulting data, and the provided documentation are described in this article. The resulting data and documentation are available electronically.

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