Numerical Modeling of Near Fault Seismic Ground Motion for Denali Fault

2021 ◽  
Vol 12 (2) ◽  
pp. 0-0
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Numerical Study ◽  
Ground Motions ◽  
Numerical Results ◽  
Fault Rupture ◽  
Ground Acceleration ◽  
Denali Fault ◽  
Near Fault ◽  
Good Agreement

An effective earthquake (Mw 7.9) struck Alaska on 3 November, 2002. This earthquake ruptured 340 km along Susitna Glacier, Denali and Totschunda faults in central Alaska. The peak ground acceleration (PGA) was recorded about 0.32 g at station PS10, which was located 3 km from the fault rupture. The PGA would have recorded a high value, if more instruments had been installed in the region. A numerical study has been conducted to find out the possible ground motion record that could occur at maximum horizontal slip during the Denali earthquake. The current study overcomes the limitation of number of elements to model the Denali fault. These numerical results are compared with observed ground motions. It is observed that the ground motions obtained through numerical analysis are in good agreement with observed ground motions. From numerical results, it is observed that the possible expected PGA is 0.62 g at maximum horizontal slip of Denali fault.

On strong ground motion estimates based on models of the radiated spectrum

1985 ◽  
Vol 75 (3) ◽  
pp. 641-649
Author(s):  
J. Enrique Luco
Keyword(s):  
Ground Motion ◽  
Stress Drop ◽  
Peak Ground Acceleration ◽  
Strong Ground Motion ◽  
Source Model ◽  
Spectral Model ◽  
Ground Acceleration ◽  
A Value ◽  
Strong Ground ◽  
Good Agreement

Abstract Estimates for peak ground acceleration and velocity were obtained by use of the approach of Hanks and McGuire (1981) and Boore (1983) for a model of the radiated spectrum corresponding to Brune's ω−2 source model modified by an exponentially decreasing function of frequency. This modification was suggested by the work of Anderson and Hough (1984) on spectral amplitudes. For this spectral model, it was found that it is not possible to determine a value for the stress drop parameter such that agreement with data is obtained for both peak accelerations and velocities. This finding contrasts with that of Boore (1983) who found good agreement with data by introducing an artificial cut-off frequency of 15 Hz.

Bayesian Estimations of Peak Ground Acceleration and 5% Damped Spectral Acceleration from Modified Mercalli Intensity Data

2003 ◽  
Vol 19 (3) ◽  
pp. 511-529 ◽  
Author(s):  
John E. Ebel ◽  
David J. Wald
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Ground Motions ◽  
Spectral Acceleration ◽  
Intensity Data ◽  
Ground Acceleration ◽  
Data Set ◽  
Motion Data ◽  
Ground Motion Attenuation ◽  
Quantitative Estimates

We describe a new probabilistic method that uses observations of modified Mercalli intensity (MMI) from past earthquakes to make quantitative estimates of ground shaking parameters (i.e., peak ground acceleration, peak ground velocity, 5% damped spectral acceleration values, etc.). The method uses a Bayesian approach to make quantitative estimates of the probabilities of different levels of ground motions from intensity data given an earthquake of known location and magnitude. The method utilizes probability distributions from an intensity/ground motion data set along with a ground motion attenuation relation to estimate the ground motion from intensity. The ground motions with the highest probabilities are the ones most likely experienced at the site of the MMI observation. We test the method using MMI/ground motion data from California and published ground motion attenuation relations to estimate the ground motions for several earthquakes: 1999 Hector Mine, California (M7.1); 1988 Saguenay, Quebec (M5.9); and 1982 Gaza, New Hampshire (M4.4). In an example where the method is applied to a historic earthquake, we estimate that the peak ground accelerations associated with the 1727 (M∼5.2) earthquake at Newbury, Massachusetts, ranged from 0.23 g at Newbury to 0.06 g at Boston.

scholarly journals Analysis of accelerograms—Parkfield earthquake

1967 ◽  
Vol 57 (6) ◽  
pp. 1193-1220 ◽  
Author(s):  
G. W. Housner ◽  
M. D. Trifunac
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Horizontal Displacement ◽  
Ground Acceleration ◽  
Directional Characteristic ◽  
Maximum Acceleration ◽  
Small Magnitude ◽  
Near Fault ◽  
Parkfield Earthquake

Abstract Integrated velocities and displacements show that near the fault at Cholame the surface motion exhibited a transient horizontal displacement pulse of approximately ten inches amplitude and one and one-half seconds duration, normal to the fault. Although 50 per cent of g ground acceleration was recorded at the fault, the ground motion attenuated rapidly with distance and at ten miles from the fault the maximum acceleration was reduced to one-tenth of its near-fault value. The ground motion also changed its character with distance, losing its pulse-like directional characteristic and becoming isotropic. Computed response spectra are presented and the large spectrum ordinates for this shock of relatively small magnitude and moderate destructiveness indicate that in an engineering sense the Parkfield ground motion is in a different class from such large destructive ground motions as El Centro 1940, Tehachapi 1952, and Olympia 1949.

Site effects of the Denis-Perron dam (SM-3): A case study in Eastern North America

2021 ◽  
pp. 875529302110194
Author(s):  
Daniel Verret ◽  
Denis LeBœuf ◽  
Éric Péloquin
Keyword(s):  
North America ◽  
Ground Motion ◽  
Site Effects ◽  
Transfer Functions ◽  
Ground Motions ◽  
Published Data ◽  
Eastern North America ◽  
Ground Acceleration ◽  
Large Dams ◽  
Moderate Seismicity

Eastern North America (ENA) is part of a region with low-to-moderate seismicity; nonetheless, some significant seismic events have occurred in the last few decades. Recent events have reemphasized the need to review ENA seismicity and ground motion models, along with continually reevaluating and updating procedures related to the seismic safety assessment of hydroelectric infrastructures, particularly large dams in Québec. Furthermore, recent researchers have shown that site-specific characteristics, topography, and valley shapes may significantly aggravate the severity of ground motions. To the best of our knowledge, very few instrumental data from actual earthquakes have been published for examining the site effects of hydroelectric dam structures located in eastern Canada. This article presents an analysis of three small earthquakes that occurred in 1999 and 2002 at the Denis-Perron (SM-3) dam. This dam, the highest in Québec, is a rockfill embankment structure with a height of 171 m and a length of 378 m; it is located in a narrow valley. The ground motion datasets of these earthquakes include the bedrock and dam crest three-component accelerometer recordings. Ground motions are analyzed both in the time and frequency domains. The spectral ratios and transfer functions obtained from these small earthquakes provide new insights into the directionality of resonant frequencies, vibration modes, and site effects for the Denis-Perron dam. The crest amplifications observed for this dam are also compared with previously published data for large dams. New statistical relationships are proposed to establish dam crest amplification on the basis of the peak ground acceleration (PGA) at the foundation.

Deterministic 3D Ground-Motion Simulations (0–5 Hz) and Surface Topography Effects of the 30 October 2016 Mw 6.5 Norcia, Italy, Earthquake

2021 ◽  
Author(s):  
Arben Pitarka ◽  
Aybige Akinci ◽  
Pasquale De Gori ◽  
Mauro Buttinelli
Keyword(s):  
Surface Topography ◽  
Ground Motion ◽  
Seismic Station ◽  
Ground Motions ◽  
Peak Ground Velocity ◽  
Earth Model ◽  
Rupture Directivity ◽  
Epicentral Area ◽  
Near Fault ◽  
Local Topography

ABSTRACT The Mw 6.5 Norcia, Italy, earthquake occurred on 30 October 2016 and caused extensive damage to buildings in the epicentral area. The earthquake was recorded by a network of strong-motion stations, including 14 stations located within a 5 km distance from the two causative faults. We used a numerical approach for generating seismic waves from two hybrid deterministic and stochastic kinematic fault rupture models propagating through a 3D Earth model derived from seismic tomography and local geology. The broadband simulations were performed in the 0–5 Hz frequency range using a physics-based deterministic approach modeling the earthquake rupture and elastic wave propagation. We used SW4, a finite-difference code that uses a conforming curvilinear mesh, designed to model surface topography with high numerical accuracy. The simulations reproduce the amplitude and duration of observed near-fault ground motions. Our results also suggest that due to the local fault-slip pattern and upward rupture directivity, the spatial pattern of the horizontal near-fault ground motion generated during the earthquake was complex and characterized by several local minima and maxima. Some of these local ground-motion maxima in the near-fault region were not observed because of the sparse station coverage. The simulated peak ground velocity (PGV) is higher than both the recorded PGV and predicted PGV based on empirical models for several areas located above the fault planes. Ground motions calculated with and without surface topography indicate that, on average, the local topography amplifies the ground-motion velocity by 30%. There is correlation between the PGV and local topography, with the PGV being higher at hilltops. In contrast, spatial variations of simulated PGA do not correlate with the surface topography. Simulated ground motions are important for seismic hazard and engineering assessments for areas that lack seismic station coverage and historical recordings from large damaging earthquakes.

scholarly journals Analysis of the Seismic Demand of High-Performance Buckling-Restrained Braces under a Strong Earthquake and Its Aftershocks

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Luqi Xie ◽  
Jing Wu ◽  
Qing Huang ◽  
Chao Tong
Keyword(s):  
Plastic Deformation ◽  
Ground Motion ◽  
Strong Earthquake ◽  
High Performance ◽  
Hazard Analysis ◽  
Ground Motions ◽  
Threshold Value ◽  
Seismic Demand ◽  
Near Fault ◽  
Probabilistic Seismic Demand

The analysis of the ductility and cumulative plastic deformation (CPD) demand of a high-performance buckling-restrained brace (HPBRB) under a strong earthquake and its aftershocks is conducted in this paper. A combination of three continuous excitations with the same ground motion is used to simulate the affection of a strong earthquake and its aftershocks. A six-story HPBRB frame (HPBRBF) is taken as an example to conduct the incremental dynamic analysis (IDA). The seismic responses of the HPBRBF under one, two, and three constant continuous ground motions are compared. The IDA result indicates that the ductility and CPD demand of the BRBs under the three constant continuous ground motions are significantly larger than that excited by only one. Probabilistic seismic demand analysis (PSDA) is performed using seven near-fault ground motions and seven far-fault ground motions to consider the indeterminacy of ground motion. The probabilistic seismic demand curves (PSDCs) for the ductility and CPD demand for the HPBRB under the strong earthquake and its aftershocks are obtained in combining the probabilistic seismic hazard analysis. The results indicate that the AISC threshold value of the CPD with 200 is excessively low for a HPBRBF which suffers the continuous strong aftershocks with near-fault excitations, and a stricter threshold value should be suggested to ensure the ductility and plastic deformation capacity demand of the HPBRB.

scholarly journals Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders

2020 ◽  
Vol 10 (13) ◽  
pp. 4505 ◽  
Author(s):  
Anna Banas ◽  
Robert Jankowski
Keyword(s):  
Natural Vibration ◽  
Numerical Study ◽  
Numerical Results ◽  
Vibration Exciter ◽  
Structural Vibrations ◽  
Impulse Load ◽  
Different Shapes ◽  
Comfort Criteria ◽  
Good Agreement

The paper presents the experimental and numerical results of the dynamic system identification and verification of the behavior of two footbridges in Poland. The experimental part of the study involved vibration testing under different scenarios of human-induced load, impulse load, and excitations induced by vibration exciter. Based on the results obtained, the identification of dynamic parameters of the footbridges was performed using the peak-picking method. With the impulse load applied to both structures, determination of their natural vibration frequencies was possible. Then, based on the design drawings, detailed finite element method (FEM) models were developed, and the numerical analyses were carried out. The comparison between experimental and numerical results obtained from the modal analysis showed a good agreement. The results also indicated that both structures under investigation have the first natural bending frequency of the deck in the range of human-induced excitation. Therefore, the risk of excessive structural vibrations caused by pedestrian loading was then analysed for both structures. The vibration comfort criteria for both footbridges were checked according to Sétra guidelines. In the case of the first footbridge, the results showed that the comfort criteria are fulfilled, regardless of the type of load. For the second footbridge, it was emphasized that the structure meets the assumptions of the guidelines for vibration severability in normal use; nevertheless, it is susceptible to excitations induced by synchronized users, even in the case of a small group of pedestrians.

Conditional Ground-Motion Model for Damaging Characteristics of Near-Fault Ground Motions Based on Instantaneous Power

2020 ◽  
Vol 110 (6) ◽  
pp. 2828-2842
Author(s):  
Esra Zengin ◽  
Norman Abrahamson
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Accurate Estimation ◽  
Spectral Acceleration ◽  
Motion Model ◽  
Velocity Pulse ◽  
Near Fault ◽  
Instantaneous Power ◽  
Ground Motion Model ◽  
Short Time

ABSTRACT The velocity pulse in near-fault ground motions has been used as a key characteristic of damaging ground motions. Characterization of the velocity pulse involves three parameters: presence of the pulse, period of the pulse, and amplitude of the pulse. The basic concept behind the velocity pulse is that a large amount of seismic energy is packed into a short time, leading to larger demands on the structure. An intensity measure for near-fault ground motions, which is a direct measure of the amount of energy arriving in short time, called instantaneous power (IP (T1)), is defined as the maximum power of the bandpass-filtered velocity time series measured over a time interval of 0.5T1, in which T1 is the fundamental period of the structure. The records are bandpass filtered in the period band (0.2T1−3T1) to remove the frequencies that are not expected to excite the structure. Zengin and Abrahamson (2020) showed that the drift is better correlated with the IP (T1) than with the velocity pulse parameters for records scaled to the same spectral acceleration at T1. A conditional ground-motion model (GMM) for the IP is developed based on the 5%-damped spectral acceleration at T1, the earthquake magnitude, and the rupture distance. This conditional GMM can be used for record selection for near-fault ground motions that captures the key features of velocity pulses and can lead to a better representation of the median and variability of the maximum interstory drift. The conditional GMM can also be used in a vector hazard analysis for spectral acceleration (T1) and IP (T1) that can be used for more accurate estimation of drift hazard and seismic risk.

Characterization of Ground Response and Liquefaction for Kathmandu City Based on 2015 Earthquake Using Total Stress and Effective Stress Approach

2020 ◽  
Vol 11 (2) ◽  
pp. 1-25
Author(s):  
Shiv Shankar Kumar ◽  
Pradeep Acharya ◽  
Pradeep Kumar Dammala ◽  
Murali Krishna Adapa
Keyword(s):  
Peak Ground Acceleration ◽  
Seismic Vulnerability ◽  
Ground Motions ◽  
Total Stress ◽  
Ground Response ◽  
Ground Acceleration ◽  
Liquefaction Potential ◽  
Potential Index ◽  
Semi Empirical

This chapter presents the seismic vulnerability of Kathmandu City (Nepal), based on Nepal 2015 earthquake, in terms of the ground response and liquefaction potential. The spatially well-distributed 10-boreholes and ground motions of Mw 7.8 Nepal 2015 earthquake recorded at five different stations were adopted for the analysis. The range of peak ground acceleration and peak spectral acceleration were in the order of 0.21g-0.42g and 0.74g-1.50g, respectively. Liquefaction potential of the sites were computed using both semi-empirical approach and liquefaction potential index (LPI). LPI shows that the 6 sites out of 10 sites are at high risk of liquefaction.

Sign in / Sign up

Export Citation Format

Share Document