Nonlinear Response Potential of Real versus Simulated Ground Motions for the 11 March 2011 Tohoku-oki Earthquake

2015 ◽  
Vol 31 (3) ◽  
pp. 1711-1734 ◽  
Author(s):  
Katsuichiro Goda ◽  
Susumu Kurahashi ◽  
Hadi Ghofrani ◽  
Gail M. Atkinson ◽  
Kojiro Irikura
Keyword(s):  
Nonlinear Response ◽  
Main Shock ◽  
Strong Motion ◽  
Motion Generation ◽  
Demand Curves ◽  
Finite Fault ◽  
Time Histories ◽  
Ground Motion Records ◽  
Finite Fault Method ◽  
Simulated Ground Motions

This study compares the nonlinear response potential of generic inelastic single-degree-of-freedom systems subjected to three sets of ground motion records for the 2011 Tohoku main shock. The compared record sets, all for the same sites, are: (1) observed accelerograms at 48 KiK-net strong motion stations; (2) time-histories simulated from the empirical Green's function method; and (3) time-histories simulated using the stochastic finite-fault method (with multiple sub-events). The adopted techniques can capture a realistic source rupture process involving multiple strong motion generation areas in simulations. Statistical analysis of computed peak ductility demands for the three record sets is conducted via cloud and stripe analyses. Results indicate that for the 2011 Tohoku main shock, different record sets produce similar average trends of the inelastic seismic demand curves. This conclusion is applicable to both cloud and stripe approaches and to structural systems with degrading and pinching hysteresis.

An Improved Stochastic Finite-Fault Method Based on Energy

2015 ◽  
Vol 744-746 ◽  
pp. 878-883
Author(s):  
Ju Fang Zhong ◽  
Jun Wei Liang ◽  
Zhi Peng Fan ◽  
Luo Long Zhan
Keyword(s):  
Ground Motion ◽  
Amplification Factor ◽  
Response Spectrum ◽  
Near Field ◽  
Energy Accumulation ◽  
Accumulation Curve ◽  
Finite Fault ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Finite Fault Method

Owing to the simulated ground motion energy distribution by stochastic finite-fault method is not reasonable, near-field bedrock strong ground motion acceleration time histories are used to study. Fourier transform is adapted to analysis the variation of the energy accumulation curve with frequency. The results show that the record energy accumulation curve is a steep rise curve, 80% of total energy of the vertical ground motion is concentrated on the 2.5-15Hz, while the horizontal is mainly concentrated on the 2-11Hz. An improved stochastic finite-fault method is proposed by multiplying an amplification factor in some frequency. The results show that multiplying an amplification factor, the simulated acceleration energy accumulation curve matches to the record acceleration energy accumulation curve, and the peak of simulated acceleration response spectrum tends to the record acceleration value.

Earthquake time histories compatible with the 2005 National building code of Canada uniform hazard spectrum

2009 ◽  
Vol 36 (6) ◽  
pp. 991-1000 ◽  
Author(s):  
Gail M. Atkinson
Keyword(s):  
Ground Motions ◽  
Time History ◽  
Building Code ◽  
Site Condition ◽  
Period Range ◽  
Uniform Hazard Spectrum ◽  
Finite Fault ◽  
Time Histories ◽  
Finite Fault Method ◽  
Site Classes

The seismic design provisions of the 2005 National building code of Canada (NBCC) (NRC 2005) describe earthquake ground motions for which structures are to be designed in terms of a uniform hazard spectrum (UHS) having a 2% chance of being exceeded in 50 years. The “target” UHS depends on location and site condition, where site condition is described by a classification scheme based on the time-averaged shear-wave velocity in the top 30 m of the deposit. For some applications, such as dynamic analysis by time history methods, it is useful to have time histories that represent the types of earthquake motions expected and match the target UHS from the NBCC over some prescribed period range. In this study, the stochastic finite-fault method is used to generate earthquake time histories that may be used to match the 2005 NBCC UHS for a range of Canadian sites. Records are provided for site classes A, C, D, and E. They are freely available at www.seismotoolbox.ca .

Prediction of Broadband Ground-Motion Time Histories: The Case of Tehran, Iran

2013 ◽  
Vol 29 (2) ◽  
pp. 633-660 ◽  
Author(s):  
Hamid Zafarani ◽  
Hesam Vahidifard ◽  
Anooshirvan Ansari
Keyword(s):  
Ground Motion ◽  
Strong Motion ◽  
Historical Earthquakes ◽  
Response Spectra ◽  
Wave Number ◽  
Corner Frequency ◽  
Earthquake Scenarios ◽  
Motion Time ◽  
Finite Fault ◽  
Time Histories

The northern Tehran fault (NTF) is potentially capable of causing large earth-quakes (Mmax ~ 7.2) in a very densely populated area of northern Tehran, Iran. Due to the lack of recorded strong motion data for earthquakes on the fault, a hybrid simulation method is used to calculate broadband (0.1–20 Hz) ground-motion time histories at bedrock level for deterministic earthquake scenarios on the NTF. Low-frequency components of motion (0.1–1.0 Hz) are calculated using a deterministic approach and the discrete wave number-finite element method in a regional one-dimensional (1-D) velocity model. High frequencies (1.0–20.0 Hz) are calculated by the stochastic finite fault method based on dynamic corner frequency. The results were validated by comparing the simulated peak values and response spectra with the empirical ground motion models available for the area and the Modified Mercalli intensity (MMI) observations from historical earthquakes of the region.

Stochastic Analysis of the Kamishiro Earthquake Considering a Dynamic Fault Rupture

2018 ◽  
Vol 12 (04) ◽  
pp. 1841009
Author(s):  
Yuta Mitsuhashi ◽  
Gaku Hashimoto ◽  
Hiroshi Okuda ◽  
Fujio Uchiyama
Keyword(s):  
Large Scale ◽  
Time History ◽  
Strong Motion ◽  
Bayesian Optimization ◽  
Underground Structures ◽  
Dynamic Rupture ◽  
Motion Generation ◽  
Nonlinear Fem ◽  
Need To Evaluate ◽  
Time Histories

In recent years, a new demand has appeared for evaluations of earthquake fault displacements, to address the need to evaluate the soundness of underground structures. Fault displacements are caused by the rupturing of earthquake source faults, and are investigated through the use of methods such as the finite difference method and the finite element method (FEM). We conducted dynamic rupture simulations on the Kamishiro Fault Earthquake using a nonlinear FEM, focused on time history of fault displacement and response displacement, and demonstrated an ability to simulate observed values to a certain extent. During these simulations, we created models of homogeneous faults using the ground as the solid element and fault planes as joint elements. Although we were able to roughly simulate displacement time histories, obstacles to achieving more precise simulations still exist. In this research, we conducted investigations to model strong motion generation areas (SMGA). We conducted a searching analysis using Bayesian optimization with SMGA distribution within faults as parameters, and estimated the optimal parameters for simulating time histories of displacement. In addition, we compared our results with estimations of SMGA derived from different methods, and demonstrated that our distributions qualitatively matched. In addition, we evaluated the stochasticity of response displacement considering the randomness of the parameter of the fault. To conduct the simulation, we introduced joint elements from Goodman et al. that had been expanded to the FEM code FrontISTR, which makes it possible to analyze large-scale models.

THE EMPIRICAL GREEN’S FUNCTION TECHNIQUE MODIFICATION FOR ACCELEROGRAM SYNTHESIS IN LOWSEISMICITY REGIONS

2018 ◽  
Vol 12 (5-6) ◽  
pp. 72-80
Author(s):  
A. A. Krylov
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Main Shock ◽  
Amplitude Spectrum ◽  
Strong Motion ◽  
Function Technique ◽  
Focal Region ◽  
Empirical Green’S Function ◽  
Epicentral Zone ◽  
Empirical Green's Function

In the absence of strong motion records at the future construction sites, different theoretical and semi-empirical approaches are used to estimate the initial seismic vibrations of the soil. If there are records of weak earthquakes on the site and the parameters of the fault that generates the calculated earthquake are known, then the empirical Green’s function can be used. Initially, the empirical Green’s function method in the formulation of Irikura was applied for main shock record modelling using its aftershocks under the following conditions: the magnitude of the weak event is only 1–2 units smaller than the magnitude of the main shock; the focus of the weak event is localized in the focal region of a strong event, hearth, and it should be the same for both events. However, short-termed local instrumental seismological investigation, especially on seafloor, results usually with weak microearthquakes recordings. The magnitude of the observed micro-earthquakes is much lower than of the modeling event (more than 2). To test whether the method of the empirical Green’s function can be applied under these conditions, the accelerograms of the main shock of the earthquake in L'Aquila (6.04.09) with a magnitude Mw = 6.3 were modelled. The microearthquake with ML = 3,3 (21.05.2011) and unknown origin mechanism located in mainshock’s epicentral zone was used as the empirical Green’s function. It was concluded that the empirical Green’s function is to be preprocessed. The complex Fourier spectrum smoothing by moving average was suggested. After the smoothing the inverses Fourier transform results with new Green’s function. Thus, not only the amplitude spectrum is smoothed out, but also the phase spectrum. After such preliminary processing, the spectra of the calculated accelerograms and recorded correspond to each other much better. The modelling demonstrate good results within frequency range 0,1–10 Hz, considered usually for engineering seismological studies.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Control of rupture by fault geometry during the 1966 parkfield earthquake

1981 ◽  
Vol 71 (1) ◽  
pp. 95-116 ◽  
Author(s):  
Allan G. Lindh ◽  
David M. Boore
Keyword(s):  
Main Shock ◽  
Fault Plane ◽  
San Andreas Fault ◽  
Strong Motion ◽  
P Wave ◽  
Fault Geometry ◽  
Dynamic Rupture ◽  
San Andreas ◽  
Hill Station ◽  
Parkfield Earthquake

abstract A reanalysis of the available data for the 1966 Parkfield, California, earthquake (ML=512) suggests that although the ground breakage and aftershocks extended about 40 km along the San Andreas Fault, the initial dynamic rupture was only 20 to 25 km in length. The foreshocks and the point of initiation of the main event locate at a small bend in the mapped trace of the fault. Detailed analysis of the P-wave first motions from these events at the Gold Hill station, 20 km southeast, indicates that the bend in the fault extends to depth and apparently represents a physical discontinuity on the fault plane. Other evidence suggests that this discontinuity plays an important part in the recurrence of similar magnitude 5 to 6 earthquakes at Parkfield. Analysis of the strong-motion records suggests that the rupture stopped at another discontinuity in the fault plane, an en-echelon offset near Gold Hill that lies at the boundary on the San Andreas Fault between the zone of aseismic slip and the locked zone on which the great 1857 earthquake occurred. Foreshocks to the 1857 earthquake occurred in this area (Sieh, 1978), and the epicenter of the main shock may have coincided with the offset zone. If it did, a detailed study of the geological and geophysical character of the region might be rewarding in terms of understanding how and why great earthquakes initiate where they do.

i1-net: The Iran Strong Motion Network

2021 ◽  
Author(s):  
Mohammad Pourmohammad Shahvar ◽  
Esmaeil Farzanegan ◽  
Attiyeh Eshaghi ◽  
Hossein Mirzaei
Keyword(s):  
Earthquake Engineering ◽  
Strong Motion ◽  
Current Status ◽  
Primary Input ◽  
The Road ◽  
Leading Position ◽  
Hazard And Risk ◽  
Ground Motion Records ◽  
Strong Motion Network ◽  
Strong Ground

Abstract Strong ground-motion records are the primary input data in earthquake engineering studies to improve understanding of seismic hazard and risk. As the overseer of the Iran Strong Motion Network (i1-net), the Road, Housing, and Urban Development Research Center occupies the leading position in this field in the country. With more than 1260 active accelerometers and a collection of over 14,129 earthquake recordings since 1973, the Iran Strong Motion Network is the major Iranian source of information for engineering seismology and earthquake engineering. The present article describes the current status and developments of the i1-net in the last 46 yr.

Are Near-Fault Fling Effects Captured in the New NGA West2 Ground Motion Models?

2015 ◽  
Vol 31 (3) ◽  
pp. 1629-1645 ◽  
Author(s):  
Ronnie Kamai ◽  
Norman Abrahamson
Keyword(s):  
Ground Motion ◽  
Vertical Component ◽  
Strong Motion ◽  
Motion Processing ◽  
Large Set ◽  
Pass Filter ◽  
Motion Models ◽  
Finite Fault ◽  
Maximum Period ◽  
Ground Motion Models

We evaluate how much of the fling effect is removed from the NGA database and accompanying GMPEs due to standard strong motion processing. The analysis uses a large set of finite-fault simulations, processed with four different high-pass filter corners, representing the distribution within the PEER ground motion database. The effects of processing on the average horizontal component, the vertical component, and peak ground motion values are evaluated by taking the ratio between unprocessed and processed values. The results show that PGA, PGV, and other spectral values are not significantly affected by processing, partly thanks to the maximum period constraint used when developing the NGA GMPEs, but that the bias in peak ground displacement should not be ignored.

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