Uniform Hazard Ground Motions for Mid-America Cities

2001 ◽  
Vol 17 (2) ◽  
pp. 359-384 ◽  
Author(s):  
Y. K. Wen ◽  
C. L. Wu
Keyword(s):  
Performance Evaluation ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Source Model ◽  
Motion Models ◽  
Finite Fault ◽  
Hazard Response ◽  
Linear And Nonlinear ◽  
Finite Fault Model

For performance evaluation of buildings and structures, synthetic uniform hazard (10% and 2% in 50 years) ground motions are generated for Memphis, Tennessee, St. Louis, Missouri, and Carbondale, Illinois. The method of simulation is based on the latest regional seismic information and stochastic ground motion models. Both point-source model and finite-fault model are used and the effects of soil profile are considered. The emphasis is on treatment of uncertainty and efficiency in application to evaluation of structural performance in both the linear and nonlinear range. The results show that the uniform hazard response spectra calculated from the simulated motions are comparable to those corresponding to USGS hazard maps. The suites of ten ground motions selected to match the uniform hazard response spectra represent events of different magnitudes, distances, and attenuation. The median value of the structural response to the selected ground motions matches closely the uniform hazard linear and nonlinear response spectra based on nine thousand ground motions and has a coefficient of variation of less than 10%. The suites of uniform hazard ground motions therefore can be used in probabilistic performance evaluation with good accuracy and efficiency.

Synthesis of Strong Ground Motions at Two Rock Stations during the Great Wenchuan Earthquake from a Hybrid Source Model

2013 ◽  
Vol 353-356 ◽  
pp. 1923-1929 ◽  
Author(s):  
Xia Xin Tao ◽  
Hai Ming Liu ◽  
Li Yuan Wang ◽  
Jiang Wei
Keyword(s):  
Wenchuan Earthquake ◽  
Response Spectrum ◽  
Ground Motions ◽  
Response Spectra ◽  
Source Model ◽  
Finite Fault ◽  
Time Histories ◽  
Source Models ◽  
Truncated Normal ◽  
Global And Local

In order to study the characteristics of ground motions at the two dam sites damaged during the great Wenchuan earthquake in 2008, the motions at two observation stations nearby are synthesized in this paper. 30 finite fault based hybrid source models of the great Wenchuan earthquake with magnitude 8.0 is built. The global and local parameters are both generated from the truncated Normal distribution with mean and standard deviation values estimated by a set of semi-experiential calibration laws and from the regional seismo-tectonics, structure of the crust, and seismicity. A representative source model is then chosen from the corresponding response spectrum mostly close to the average one. The result motions are presented, and the characteristics of the time histories, response spectra and the peak accelerations are quite close to the recordings.

Seismic Hazard Analysis for an NPP Site

2004 ◽  
Author(s):  
A. K. Ghosh ◽  
H. S. Kushwaha
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Hazard Analysis ◽  
Structural Response ◽  
Response Spectra ◽  
Seismic Fragility ◽  
Material Strength ◽  
Ground Acceleration ◽  
Hazard Response

The various uncertainties and randomness associated with the occurrence of earthquakes and the consequences of their effects on the NPP components and structures call for a probabilistic seismic risk assessment (PSRA). However, traditionally, the seismic design basis ground motion has been specified by normalised response spectral shapes and peak ground acceleration (PGA). The mean recurrence interval (MRI) used to be computed for PGA only. The present work develops uniform hazard response spectra i.e. spectra having the same MRI at all frequencies for Kakrapar Atomic Power Station site. Sensitivity of the results to the changes in various parameters has also been presented. These results determine the seismic hazard at the given site and the associated uncertainties. The paper also presents some results of the seismic fragility for an existing containment structure. The various parameters that could affect the seismic structural response include material strength of concrete, structural damping available within the structure and the normalized ground motion response spectral shape. Based on this limited case study the seismic fragility of the structure is developed. The results are presented as families of conditional probability curves plotted against the peak ground acceleration (PGA). The procedure adopted incorporates the various randomness and uncertainty associated with the parameters under consideration.

Drift Spectrum vs. Modal Analysis of Structural Response to Near-Fault Ground Motions

2001 ◽  
Vol 17 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Anil K. Chopra ◽  
Chatpan Chintanapakdee
Keyword(s):  
Earthquake Engineering ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Engineering Practice ◽  
Drift Spectrum ◽  
Combination Rules ◽  
Near Fault ◽  
Far Fault

A new measure of earthquake demand, the drift spectrum has been developed as an adjunct to the response spectrum, a central concept in earthquake engineering, in calculating the internal deformations of a structure due to near-fault ground motions with pronounced coherent pulses in the velocity and displacement histories. Compared in this paper are certain aspects of the elastic structural response to near-fault and far-fault ground motions. It is demonstrated that (1) the difference between drift and response spectra are not unique to near-fault ground motions; these differences simply reflect higher-mode response, which is larger due to near-fault ground motions; (2) response spectrum analysis (RSA) using existing modal combination rules can provide an estimate of structural response that is accurate to a useful degree; (3) these modal combination rules are similarly accurate for near-fault and far-fault ground motions although the underlying assumptions are not satisfied by near-fault excitations; and (4) RSA is preferable over the drift spectrum in computing structural response because it represents standard engineering practice and is applicable to a wide variety of structures.

scholarly journals Surface Level Synthetic Ground Motions for M7.6 2001 Gujarat Earthquake

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 429 ◽  
Author(s):  
Jayaprakash Vemuri ◽  
Subramaniam Kolluru ◽  
Sumer Chopra
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Peak Ground Velocity ◽  
Seismic Zone ◽  
Spectral Acceleration ◽  
Surface Level ◽  
Seismic Code ◽  
Code Of Practice ◽  
Finite Fault

The 2001 Gujarat earthquake was one of the most destructive intraplate earthquakes ever recorded. It had a moment magnitude of M w 7.6 and had a maximum felt intensity of X on the Modified Mercalli Intensity scale. No strong ground motion records are available for this earthquake, barring PGA values recorded on structural response recorders at thirteen sites. In this paper, synthetic ground motions are generated at surface level using the stochastic finite-fault method. Available PGA data from thirteen stations are used to validate the synthetic ground motions. The validated methodology is extended to various sites in Gujarat. Response spectra of synthetic ground motions are compared with the prescribed spectra based on the seismic zonation given in the Indian seismic code of practice. Ground motion characteristics such as peak ground acceleration, peak ground velocity, frequency content, significant duration, and energy content of the ground motions are analyzed. Response spectra of ground motions for towns situated in the highest zone, seismic zone 5, exceeded the prescribed spectral acceleration of 0.9 g for the maximum considered earthquake. The response spectra for towns in seismic zone 5 exhibit peaks in the low period ranges, indicating high vulnerability of low rise structures designed as per the provisions of the Indian seismic code of practice. The response spectra for towns situated in seismic zone 3 were considerably lower than the prescribed maximum spectral acceleration of 0.4 g. The substantial damage reported in towns situated in seismic zone 3 is due to poor construction practices and non-compliance with provisions of seismic design standards.

scholarly journals Characteristics of strong ground motion attenuation in the 2019 Mw 5.8 Changning earthquake, Sichuan, China

2021 ◽  
Author(s):  
J. J. Hu ◽  
H. Zhang ◽  
J. B. Zhu ◽  
G. H. Liu
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Peak Ground Velocity ◽  
Arias Intensity ◽  
Ground Acceleration ◽  
Motion Models ◽  
Ground Motion Attenuation ◽  
Short Period ◽  
Strong Ground

AbstractA moderate magnitude earthquake with Mw 5.8 occurred on June 17, 2019, in Changning County, Sichuan Province, China, causing 13 deaths, 226 injuries, and serious engineering damage. This earthquake induced heavier damage than earthquakes of similar magnitude. To explain this phenomenon in terms of ground motion characteristics, based on 58 sets of strong ground motions in this earthquake, the peak ground acceleration (PGA), peak ground velocity (PGV), acceleration response spectra (Sa), duration, and Arias intensity are analyzed. The results show that the PGA, PGV, and Sa are larger than the predicted values from some global ground motion models. The between-event residuals reveal that the source effects on the intermediate-period and long-period ground motions are stronger than those on short-period ground motions. Comparison of Arias intensity attenuation with the global models indicates that the energy of ground motions of the Changning earthquake is larger than those of earthquakes with the same magnitude.

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.

scholarly journals Normal Faulting in the 2020 Mw 6.2 Yutian Event: Implications for Ongoing E–W Thinning in Northern Tibet

2020 ◽  
Vol 12 (18) ◽  
pp. 3012
Author(s):  
Ping He ◽  
Yangmao Wen ◽  
Kaihua Ding ◽  
Caijun Xu
Keyword(s):  
Normal Fault ◽  
Source Model ◽  
Coseismic Deformation ◽  
The Tibetan Plateau ◽  
Interferometric Synthetic Aperture Radar ◽  
Local Seismicity ◽  
Northern Tibet ◽  
Finite Fault ◽  
Maximum Subsidence ◽  
Finite Fault Model

Extensional earthquakes in the Tibetan Plateau play an important role in the plateau’s orogenic evolution and cause heavy seismic hazard, yet their mechanisms remain poorly known, in particular in harsh northern Tibet. On 25 June 2020, a Mw 6.2 earthquake struck Yutian, Xinjiang, offering us a rare chance to gain insights into its mechanism and implications in the Tibetan extension. We used both descending and ascending Sentinel-1 images to generate coseismic deformation associated with this event, which indicates a typical extensional mechanism with a maximum subsidence displacement of 25 cm and minor uplift. The causative fault constrained with interferometric synthetic aperture radar (InSAR) data based on a finite fault model suggests that the fault plane has a strike of 186.4° and westward dip of 64.8°, and the main rupture is concentrated at a depth of 3.6–10.8 km with a peak slip of 0.85 m. Our source model indicates that the 2020 Yutian event ruptured an unknown high-angle blind normal fault with N–S striking. The total released geodetic moment yields 2.69 × 1018 N·m, equivalent to Mw 6.23. We used dense interseismic global positioning system (GPS) measurements to reveal an approximate 7 mm/yr extensional motion in the Yutian region, but it still does not seem large enough to support high local seismicity for normal events within 12 years, i.e., Mw 7.1 in 2008, Mw 6.2 in 2012, and this event in 2020. Combined with Coulomb stress change modeling, we speculate that the seismicity in Yutian is related to the lower lithospheric dynamics.

Engineering Characteristics of Ground Motions Recorded in the 2019 Ridgecrest Earthquake Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1474-1494 ◽  
Author(s):  
Sean Kamran Ahdi ◽  
Silvia Mazzoni ◽  
Tadahiro Kishida ◽  
Pengfei Wang ◽  
Chukwuebuka C. Nweke ◽  
...  
Keyword(s):  
Ground Motion ◽  
Fault Zone ◽  
Ground Motions ◽  
Response Spectra ◽  
Earthquake Sequence ◽  
Damage Potential ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Inelastic Response ◽  
Motion Models

ABSTRACT We present a database and analyze ground motions recorded during three events that occurred as part of the July 2019 Ridgecrest earthquake sequence: a moment magnitude (M) 6.5 foreshock on a left-lateral cross fault in the Salt Wells Valley fault zone, an M 5.5 foreshock in the Paxton Ranch fault zone, and the M 7.1 mainshock, also occurring in the Paxton Ranch fault zone. We collected and uniformly processed 1483 three-component recordings from an array of 824 sensors spanning 10 seismographic networks. We developed site metadata using available data and multiple models for the time-averaged shear-wave velocity in the upper 30 m (VS30) and for basin depth terms. We processed ground motions using Next Generation Attenuation (NGA) procedures and computed intensity measures including spectral acceleration at a number of oscillator periods and inelastic response spectra. We compared elastic and inelastic response spectra to seismic design spectra in building codes to evaluate the damage potential of the ground motions at spatially distributed sites. Residuals of the observed spectral accelerations relative to the NGA-West2 ground-motion models (GMMs) show good average agreement between observations and model predictions (event terms between about −0.3 and 0.5 for peak ground acceleration to 5 s). The average attenuation with distance is also well captured by the empirical NGA-West2 GMMs, although azimuthal variations in attenuation were observed that are not captured by the GMMs. An analysis considering directivity and fault-slip heterogeneity for the M 7.1 event demonstrates that the dispersion in the near-source ground-motion residuals can be reduced.

Simulation of Pulse-Like Ground Motions during the 2015 Mw 8.3 Illapel Earthquake with a New Source Model Using Corrected Empirical Green’s Functions

2021 ◽  
Author(s):  
Claudio Fernández ◽  
Atsushi Nozu ◽  
Jorge G. F. Crempien ◽  
Juan Carlos de la Llera
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Source Model ◽  
Primary Objective ◽  
Pulse Generation ◽  
Local Network ◽  
Generalized Inversion Technique ◽  
Wide Range ◽  
Illapel Earthquake

Abstract Pulse-like near-source ground motions were observed by the local network during the 2015 Mw 8.3 Illapel, Chile earthquake. Such ground motions can be quite damaging to a wide range of infrastructures. The primary objective of this study is to provide a source model that can explain such ground motions. The isolated nature of the pulses indicated that the rupture of some small isolated region on the fault contributed to the generation of the pulse. Therefore, we considered such regions and termed them as Strong Motion Pulse Generation Areas (SPGAs). We used the corrected empirical Green's function (EGF) method because this method has been successfully applied to near-source pulse-like ground motions in previous studies. We simulated synthetic waveforms using the frequency dependent quality factor Q=239f0.71 and empirical site amplification factors, which we obtained by applying a generalized inversion technique to local weak-motion data. The result indicated that the observed ground motions from the Mw 8.3 Illapel earthquake can readily be explained with a source model that involves two SPGAs with dimensions of several kilometers in spite of the huge rupture zone of the earthquake. The source model can reproduce velocity waveforms, acceleration Fourier amplitude spectra (FAS) and pseudoacceleration response spectra. It also reproduces the duration of strong ground motions quite accurately. No significant bias was found with respect to distance and frequency. In conclusion, the corrected EGF method is a very efficient tool to simulate near-source ground motions of a subduction earthquake when it is combined with higher stress-drop subevents whose sizes are adjusted to the observed pulse widths.

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