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.

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.

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.

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.

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.

scholarly journals Control Spectra for Quito

2016 ◽  
Author(s):  
Roberto Aguiar ◽  
Alicia Rivas-Medina ◽  
Pablo Caiza ◽  
Diego Quizanga
Keyword(s):  
Urban Areas ◽  
Slip Rate ◽  
Response Spectra ◽  
Elastic Response ◽  
Minimum Size ◽  
Physical Parameters ◽  
North Central ◽  
South Central ◽  
Elastic Response Spectra ◽  
Maximum Minimum

Abstract. The Metropolitan District of Quito is divided into five areas: south, south-central, central, north-central and north. It is located on or very close to segments of reverse blind faults: Puengasí, Ilumbisí-La Bota, Carcelen-El Inca, Bellavista-Catequilla and Tangahuilla as indicated in Alvarado et al. (2014), making it one of the most seismically dangerous cities in the world. For each of the urban areas of Quito, elastic response spectra are presented in this paper, which are found using some of the new models of the PEER's NGA-West2 Program, models developed by: Abrahamson et al. (2013), Campbell and Borzognia (2013), and Chiou and Youngs (2013). These spectra are calculated considering the maximum amount that could be generated by the rupture of each fault segments, and taking into account the soil type that exists in each zone according to the Norma Ecuatoriana de la Construcción 2015 (NEC-15). Subsequently, the recurrence period of earthquakes of high magnitude in each fault segment is determined from the physical parameters of the fault segments (size of the fault plane and slip rate), and considering that the fault can break in earthquakes of magnitude less than the expected maximum (minimum size 5.0 Mw). For this, the pattern of recurrence of type GR earthquakes (Gutenberg and Richter, 1944) with double truncation magnitude (Mmin and Mmax) proposed by Cosentino et al. (1977) is used.

Engineering observations on ground motion at the Van Norman Complex after the 1994 Northridge earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S333-S349 ◽  
Author(s):  
J. P. Bardet ◽  
C. Davis
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Low Frequency ◽  
Strong Motion ◽  
Response Spectra ◽  
Vertical Acceleration ◽  
Northridge Earthquake ◽  
Peak Acceleration ◽  
Geotechnical Earthquake Engineering ◽  
1994 Northridge Earthquake

Abstract During the 1994 Northridge earthquake, the Van Norman Complex yielded an unprecedented number of recordings with high acceleration, in the close proximity of the fault rupture. These strong-motion recordings exhibited the pulses of the main event. One station recorded the largest velocity ever instrumentally recorded (177 cm/sec), resulting from a 0.86 g peak acceleration with a low frequency. Throughout the complex, the horizontal accelerations reached peak values ranging from 0.56 to 1.0 g, except for the complex center, where the peak acceleration did not exceed 0.43 g. The vertical acceleration reached maximum peak values comparable with those of the horizontal acceleration. The acceleration response spectra in the longitudinal and transverse directions were significantly different. Such a difference, which is not yet well documented in the field of geotechnical earthquake engineering, indicates that the amplitude and frequency content of the ground motion was directionally dependent in the Van Norman Complex.

Evaluation of Earthquake Response Spectra Directionality Using Stochastic Simulations

2021 ◽  
Author(s):  
Alan Poulos ◽  
Eduardo Miranda ◽  
Jack W. Baker
Keyword(s):  
Stochastic Process ◽  
Ground Motion ◽  
Ground Motions ◽  
Gaussian White Noise ◽  
Response Spectra ◽  
Orientation Dependence ◽  
Stochastic Simulations ◽  
Earthquake Ground Motion ◽  
Significant Duration ◽  
Simulated Ground Motions

ABSTRACT For earthquake-resistant design purposes, ground-motion intensity is usually characterized using response spectra. The amplitude of response spectral ordinates of horizontal components varies significantly with changes in orientation. This change in intensity with orientation is commonly known as ground-motion directionality. Although this directionality has been attributed to several factors, such as topographic irregularities, near-fault effects, and local geologic heterogeneities, the mechanism behind this phenomenon is still not well understood. This work studies the directionality characteristics of earthquake ground-motion intensity using synthetic ground motions and compares their directionality to that of recorded ground motions. The two principal components of horizontal acceleration are sampled independently using a stochastic model based on finite-duration time-modulated filtered Gaussian white-noise processes. By using the same stochastic process to sample both horizontal components of motion, the variance of horizontal ground acceleration has negligible orientation dependence. However, these simulations’ response spectral ordinates present directionality levels comparable to those found in real ground motions. It is shown that the directionality of the simulated ground motions changes for each realization of the stochastic process and is a consequence of the duration being finite. Simulated ground motions also present similar directionality trends to recorded earthquake ground motions, such as the increase of average directionality with increasing period of vibration and decrease with increasing significant duration. These results suggest that most of the orientation dependence of horizontal response spectra is primarily explained by the finite significant duration of earthquake ground motion causing inherent randomness in response spectra, rather than by some physical mechanism causing polarization of shaking.

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