Damping Scaling Factors for Elastic Response Spectra for Shallow Crustal Earthquakes in Active Tectonic Regions: “Average” Horizontal Component

2014 ◽  
Vol 30 (2) ◽  
pp. 939-963 ◽  
Author(s):  
Sanaz Rezaeian ◽  
Yousef Bozorgnia ◽  
I. M. Idriss ◽  
Norman Abrahamson ◽  
Kenneth Campbell ◽  
...  
Keyword(s):  
Ground Motion ◽  
Damping Ratio ◽  
Response Spectra ◽  
Elastic Response ◽  
Site Conditions ◽  
Crustal Earthquakes ◽  
Nonstructural Systems ◽  
Elastic Response Spectra ◽  
Active Tectonic ◽  
Functional Forms

Ground motion prediction equations (GMPEs) for elastic response spectra are typically developed at a 5% viscous damping ratio. In reality, however, structural and nonstructural systems can have other damping ratios. This paper develops a new model for a damping scaling factor ( DSF) that can be used to adjust the 5% damped spectral ordinates predicted by a GMPE for damping ratios between 0.5% to 30%. The model is developed based on empirical data from worldwide shallow crustal earthquakes in active tectonic regions. Dependencies of the DSF on potential predictor variables, such as the damping ratio, spectral period, ground motion duration, moment magnitude, source-to-site distance, and site conditions, are examined. The strong influence of duration is captured by the inclusion of both magnitude and distance in the DSF model. Site conditions show weak influence on the DSF. The proposed damping scaling model provides functional forms for the median and logarithmic standard deviation of DSF, and is developed for both RotD50 and GMRotI50 horizontal components. A follow-up paper develops a DSF model for vertical ground motion.

Damping Scaling Factors for Vertical Elastic Response Spectra for Shallow Crustal Earthquakes in Active Tectonic Regions

2014 ◽  
Vol 30 (3) ◽  
pp. 1335-1358 ◽  
Author(s):  
Sanaz Rezaeian ◽  
Yousef Bozorgnia ◽  
I. M. Idriss ◽  
Norman A. Abrahamson ◽  
Kenneth W. Campbell ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Damping Ratio ◽  
Vertical Component ◽  
Vertical Motion ◽  
Horizontal Component ◽  
Elastic Response ◽  
Earthquake Ground Motion ◽  
Crustal Earthquakes ◽  
Elastic Response Spectra ◽  
Active Tectonic

This paper develops a new model for a damping scaling factor (DSF) that can be used to adjust elastic response spectral ordinates for the vertical component of earthquake ground motion at a 5% viscous damping ratio to ordinates at damping ratios between 0.5% and 30%. Using the extensive NGA-West2 database of recorded ground motions from worldwide shallow crustal earthquakes in active tectonic regions, a functional form for the median DSF is proposed that depends on the damping ratio, spectral period, earthquake magnitude, and distance. Standard deviation is a function of the damping ratio and spectral period. The proposed model is compared to the DSF for the “average” horizontal component. In general, the peak in DSF is shifted toward shorter periods and is farther from unity for the vertical component. Also, the standard deviation of DSF for vertical motion is slightly higher than that observed for the “average” horizontal component.

Update of the Chiou and Youngs NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra

2014 ◽  
Vol 30 (3) ◽  
pp. 1117-1153 ◽  
Author(s):  
Brian S.-J. Chiou ◽  
Robert R. Youngs
Keyword(s):  
Ground Motion ◽  
Hanging Wall ◽  
Response Spectra ◽  
Rupture Directivity ◽  
Crustal Earthquakes ◽  
Aleatory Variability ◽  
Source Distance ◽  
Active Tectonic ◽  
Peak Ground Motion ◽  
Horizontal Ground Motion

We present an update to our 2008 NGA model for predicting horizontal ground motion amplitudes caused by shallow crustal earthquakes occurring in active tectonic environments. The update is based on analysis of the greatly expanded NGA-West2 ground motion database and numerical simulations. The updated model contains minor adjustments to our 2008 functional form related to style of faulting effects, hanging wall effects, scaling with the depth to top of rupture, scaling with sediment thickness, and the inclusion of additional terms for the effects of fault dip and rupture directivity. In addition, we incorporate regional differences in far-source distance attenuation and site effects between California and other active tectonic regions. Compared to our 2008 NGA model, the predicted medians by the updated model are similar for M > 7 and are lower for M < 5. The aleatory variability is larger than that obtained in our 2008 model.

NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10 s

2008 ◽  
Vol 24 (1) ◽  
pp. 139-171 ◽  
Author(s):  
Kenneth W. Campbell ◽  
Yousef Bozorgnia
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Geometric Mean ◽  
Response Spectra ◽  
Horizontal Component ◽  
Elastic Response ◽  
Motion Model ◽  
Linear Elastic ◽  
Ground Motion Model ◽  
Elastic Response Spectra

We present a new empirical ground motion model for PGA, PGV, PGD and 5% damped linear elastic response spectra for periods ranging from 0.01–10 s. The model was developed as part of the PEER Next Generation Attenuation (NGA) project. We used a subset of the PEER NGA database for which we excluded recordings and earthquakes that were believed to be inappropriate for estimating free-field ground motions from shallow earthquake mainshocks in active tectonic regimes. We developed relations for both the median and standard deviation of the geometric mean horizontal component of ground motion that we consider to be valid for magnitudes ranging from 4.0 up to 7.5–8.5 (depending on fault mechanism) and distances ranging from 0–200 km. The model explicitly includes the effects of magnitude saturation, magnitude-dependent attenuation, style of faulting, rupture depth, hanging-wall geometry, linear and nonlinear site response, 3-D basin response, and inter-event and intra-event variability. Soil nonlinearity causes the intra-event standard deviation to depend on the amplitude of PGA on reference rock rather than on magnitude, which leads to a decrease in aleatory uncertainty at high levels of ground shaking for sites located on soil.

Vertical Ground Motion Model for PGA, PGV, and Linear Response Spectra Using the NGA-West2 Database

2016 ◽  
Vol 32 (2) ◽  
pp. 979-1004 ◽  
Author(s):  
Yousef Bozorgnia ◽  
Kenneth W. Campbell
Keyword(s):  
Ground Motion ◽  
Response Spectra ◽  
Peak Ground Velocity ◽  
Motion Model ◽  
Acceleration Response ◽  
Ground Acceleration ◽  
Ground Motion Model ◽  
Crustal Earthquakes ◽  
Active Tectonic ◽  
Vertical Ground

We summarize the development of the NGA-West2 Bozorgnia-Campbell empirical ground motion model (GMM) for the vertical components of peak ground acceleration (PGA), peak ground velocity (PGV), and 5%-damped elastic pseudo-absolute acceleration response spectra (PSA) at vertical periods ranging from 0.01 s to 10 s. In the development of the vertical GMM, similar to our 2014 horizontal GMM, we used the extensive PEER NGA-West2 worldwide database. We consider our new vertical GMM to be valid for shallow crustal earthquakes in active tectonic regions for magnitudes ranging from 3.3 to 7.5–8.5, depending on the style of faulting, and for distances as far as 300 km from the fault.

Probabilities and Fallacies: Why Hazard Maps Cannot be Validated by Individual Earthquakes

2013 ◽  
Vol 29 (3) ◽  
pp. 1125-1136 ◽  
Author(s):  
Iunio Iervolino
Keyword(s):  
Ground Motion ◽  
Best Practice ◽  
Short Note ◽  
Response Spectra ◽  
Current Approach ◽  
Elastic Response ◽  
Hazard Maps ◽  
Intensity Measures ◽  
Elastic Response Spectra ◽  
Type Of Exercise

In countries with an advanced seismic technical culture, where best-practice hazard studies (which are therefore necessarily probabilistic) are available, the occurrence of a damaging event often triggers a debate, which is as understandable as it is delicate, aimed toward the verification and/or validation of the ground motion intensity estimates provided by the official hazard maps. Evaluations such as these are typically based either on the comparison of elastic response spectra derived from records of the event in question with uniform hazard (design) spectra, or on superimposing ground motion intensity measures on available hazard curves to retrieve the return period to which they correspond. This short note, using the recent 2012 Mw 6.0 Emilia (Italy) earthquake, discusses a few arguments, according to which this type of exercise should take into account the implications inherent in the probabilistic nature of hazard analyses, in order to avoid the risk of drawing conclusions that may be misleading or that may be likely to cause misconceptions about rationality of the current approach to seismic hazard.

scholarly journals NORMALIZED ACCELERATION RESPONSE SPECTRA FOR TBILISI CITY WITH SEISMOLOGICAL PARAMETERS AND SITE EFFECTS

2014 ◽  
Author(s):  
П.А. Реквава ◽  
К. Мдивани
Keyword(s):  
Ground Motion ◽  
Direct Method ◽  
Response Spectra ◽  
Elastic Response ◽  
Earthquake Ground Motion ◽  
Soil Conditions ◽  
Vertical Acceleration ◽  
Acceleration Time Histories ◽  
Elastic Response Spectra ◽  
Wide Range

Из-за отсутствия реальных записей сильных движений целью данного исследования является разработка методологии для быстрой генерации горизонтальных и вертикальных составляющих грунтовых движений землетрясения на любом участке для города Тбилиси. Модель, разработанная в результате исследования, обеспечивает имитацию движений грунта в широком диапазоне магнитуд и расстояний при 8 очагах землетрясений в регионе Тбилиси (в пределах 50 км). Исследование включает в себя три основные темы: 1) стохастическое моделирования грунтовых движений при землетрясении для данного участка города Тбилиси 2) оценка записей ускорения в данном участке, используя прямой метод инженерной сейсмологии, рассматривая грунтовые условия, основываясь на теории отраженных волн 3) расчет горизонтального и вертикального спектров упругой реакции ускорения для основных участков территории Тбилиси. Due to lack of the real strong ground motion records the objective of this research is to develop a methodology for rapid generation of horizontal and vertical components of earthquake ground motion at any site for Tbilisi city. The model developed in this study provides simulation of ground motion over a wide range of magnitudes and distances at 8 earthquake sources zones of Tbilisi region (within 50 km). The research includes three main topics: 1) the stochastic simulation of earthquake ground motion at a given site of the city of Tbilisi 2) the estimation of acceleration time histories at a given site using the direct method of engineering seismology considering soil conditions based on the theory of the reflected waves and 3) calculation of horizontal and vertical acceleration elastic response spectra for main sites of Tbilisi territory.

Extrapolating strong ground motion of the Silakhor earthquake (ML 6.1), Iran, using the empirical Green's function (EGF) approach based on a genetic algorithm

2009 ◽  
Vol 46 (11) ◽  
pp. 801-810 ◽  
Author(s):  
Ahmad Nicknam ◽  
Reza Abbasnia ◽  
Yasser Eslamian ◽  
Mohsen Bozorgnasab
Keyword(s):  
Genetic Algorithm ◽  
Ground Motion ◽  
Green's Function ◽  
Strong Ground Motion ◽  
Strong Motion ◽  
Response Spectra ◽  
Elastic Response ◽  
Elastic Response Spectra ◽  
Input Parameters ◽  
Strong Ground

The main objectives of this article are to develop a technique to find source models that allow one to replicate observed strong ground motion records and to extrapolate strong ground motion synthesis to locations where strong motion was not recorded. A technique including the well known empirical Green’s function (EGF) approach along with a genetic algorithm is used, which allows the optimization of differences between the synthesized and observed ground shakings. The technique used is performed by comparing the elastic response spectra of observed seismograms at two stations with those of simulated data using the EGF method incorporating recorded aftershocks taken at each station. Moreover, a genetic algorithm approach is used to reduce differences between the simulated and recorded data in the form of elastic response spectra by changing the input parameters in the admissible ranges. To validate the proposed approach the three components of strong motion recorded at other stations were synthesized incorporating the input parameters obtained at previous stations. A comparatively good match of the simulated and recorded response spectra confirms the ability of the proposed technique to generate synthetic seismograms with suitable elastic response spectra.

scholarly journals NGA-West2 Empirical Fourier and Duration Models to Generate Adjustable Response Spectra

2019 ◽  
Vol 35 (1) ◽  
pp. 61-93 ◽  
Author(s):  
Sanjay Singh Bora ◽  
Fabrice Cotton ◽  
Frank Scherbaum
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Amplitude Spectrum ◽  
Response Spectra ◽  
Duration Model ◽  
Fourier Amplitude ◽  
Crustal Earthquakes ◽  
Active Tectonic ◽  
Random Vibration Theory ◽  
Fourier Amplitude Spectrum

Adjustment of median ground motion prediction equations (GMPEs) from one region to another region is one of the major challenges within the current practice of seismic hazard analysis. In our approach of generating response spectra, we derive two separate empirical models for a) Fourier amplitude spectrum (FAS) and b) duration of ground motion. To calculate response spectra, the two models are combined within the random vibration theory (RVT) framework. The models are calibrated on recordings obtained from shallow crustal earthquakes in active tectonic regions. We use a subset of NGA-West2 database with M3.2–7.9 earthquakes at distances 0–300 km. The NGA-West2 database expanded over a wide magnitude and distance range facilitates a better constraint over derived models. A frequency-dependent duration model is derived to obtain adjustable response spectral ordinates. Excellent comparison of our approach with other NGA-West2 models implies that it can also be used as a stand-alone model.

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