Seismic Hazard Assessment in the Southeastern United States

1995 ◽  
Vol 11 (1) ◽  
pp. 129-160 ◽  
Author(s):  
Paul C. Rizzo ◽  
N. R. Vaidya ◽  
E. Bazan ◽  
C. F. Heberling
Keyword(s):  
North American ◽  
Peak Ground Acceleration ◽  
Ground Motions ◽  
Near Field ◽  
Southeastern United States ◽  
Seismic Hazard Assessment ◽  
Response Spectra ◽  
Seismic Hazards ◽  
Far Field ◽  
Ground Acceleration

Comparisons of response spectra from near and far-field records to those estimated by attenuation functions commonly used in evaluating seismic hazards show that these functions provide reasonable results for near-field western North American sites. However, they estimate relatively small motions for far-field eastern North American sites, which is contrary to the empirical evidence of the 1886 Charleston and 1988 Saguenay Earthquakes. Using the 1988 Saguenay records scaled for magnitude, and several western North American records scaled to account for the slower attenuation in the east, we have developed deterministic median and 84th percentile, 5 percent damped response spectra to represent ground motions from a recurrence of the 1886 Charleston Earthquake at a distance between 85 to 120 km. The resulting 84th percentile spectrum has a shape similar to, but is less severe than, the USNRC Regulatory Guide 1.60 5 percent damped spectrum tied to a peak ground acceleration of 0.2g.

scholarly journals Evaluation of Seismic Fragility of Weir Structures in South Korea

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bu Seog Ju ◽  
WooYoung Jung
Keyword(s):  
Tensile Stress ◽  
Seismic Vulnerability ◽  
Linear Time ◽  
Ground Motions ◽  
Near Field ◽  
Time History ◽  
Fe Model ◽  
Mass Concrete ◽  
Far Field ◽  
Ground Acceleration

In order to reduce earthquake damage of multifunctional weir systems similar to a dam structure, this study focused on probabilistic seismic risk assessment of the weir structure using the fragility methodology based on Monte Carlo simulation (MCS), with emphasis on the uncertainties of the seismic ground motions in terms of near field induced pulse-like motions and far field faults. The 2D simple linear elastic plain strain finite element (FE) model including soil structure foundations using tie connection method in ABAQUS was developed to incorporate the uncertainty. In addition, five different limit states as safety criteria were defined for the seismic vulnerability of the weir system. As a consequence, the results obtained from multiple linear time history analyses revealed that the weir structure was more vulnerable to the tensile stress of the mass concrete in both near and far field ground motions specified earthquake hazard levels. In addition, the system subjected to near field motions was primarily more fragile than that under far field ground motions. On the other hand, the probability of failure due to the tensile stress at weir sill and stilling basin showed the similar trend in the overall peak ground acceleration levels.

Seismic Response Characteristics of Deep Soft Site with Depth under Far-Field Ground Motion of Great Earthquake

2011 ◽  
Vol 378-379 ◽  
pp. 477-483
Author(s):  
Ji Yan Zhan ◽  
Guo Xing Chen ◽  
Dan Dan Jin
Keyword(s):  
Peak Ground Acceleration ◽  
Response Spectrum ◽  
Ground Motions ◽  
Great Earthquake ◽  
Far Field ◽  
Acceleration Response ◽  
Ground Acceleration ◽  
Long Period ◽  
Reduction Coefficient ◽  
Acceleration Response Spectrum

Considering the dynamic nonlinear characteristics of soil by equivalent linear method, one-dimensional wave models were established to study the seismic effects along depth of deep soft sites under far-field ground motions of great earthquake. The results show that the magnified effect of acceleration response spectrum of each layer present more outstanding under far-field ground motions than under Suzhou artificial waves, with the increasing of bedrock peak ground acceleration, there is probability that the peak of long-period component of acceleration response spectrum appears higher than that of the short-period within 15m depth, which may adversely affect the long-period building structures. However, the reduction coefficient of peak ground acceleration (PGA) along depth according to the three levels of earthquake fortification standard was relatively higher when inputting far-field ground motions of great earthquake. As the curve fitted by Longjun Xu et al. based on records collected California Strong Motion Instrumentation Program geotechnical arrays of the United States and Hosokura Mine arrays of Japan, is not suitable for Suzhou area, suited quantitative formula about reduction coefficient curve of PGA with depth in deep soft site is given. Besides, maximum shear strain at the depth of approximately 15m and 40m present to be greatly changed when inputting far-field ground motions of great earthquake, with the growth of inputting bedrock peak ground acceleration, the layer in the depth of about 15m comes to be the most unfavorable position of shear deformation.

scholarly journals Seismic Fragility Analysis of Mid-Story Isolation Buildings

2021 ◽  
Keyword(s):  
Fragility Curves ◽  
Ground Motions ◽  
Near Field ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Plastic State ◽  
Far Field ◽  
Analysis Method ◽  
Isolation System ◽  
Isolation Layer

Abstract. Seismic fragility analysis is essential for seismic risk assessment of structures. This study focuses on the damage probability assessment of the mid-story isolation buildings with different locations of the isolation system. To this end, the performance-based fragility analysis method of the mid-story isolation system is proposed, adopting the maximum story drifts of structures above and below the isolation layer and displacement of the isolation layer as performance indicators. Then, the entire process of the mid-story isolation system, from the initial elastic state to the elastic-plastic state, then to the limit state, is simulated on the basis of the incremental dynamic analysis method. Seismic fragility curves are obtained for mid-story isolation buildings with different locations of the isolation layer, each with fragility curves for near-field and far-field ground motions, respectively. The results indicate that the seismic fragility probability subjected to the near-field ground motions is much greater than those subjected to the far-field ground motions. In addition, with the increase of the location of the isolation layer, the dominant components for the failure of mid-story isolated structures change from superstructure and isolation system to substructure and isolation system.

scholarly journals Seismic hazard assessment of Iran

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
B. Tavakoli ◽  
M. Ghafory-Ashtiany
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Grid Point ◽  
Seismic Hazard Assessment ◽  
Earthquake Hazard ◽  
Seismic Source ◽  
Historical Earthquakes ◽  
Earthquake Insurance ◽  
Ground Acceleration ◽  
Seismic Source Models

The development of the new seismic hazard map of Iran is based on probabilistic seismic hazard computation using the historical earthquakes data, geology, tectonics, fault activity and seismic source models in Iran. These maps have been prepared to indicate the earthquake hazard of Iran in the form of iso-acceleration contour lines, and seismic hazard zoning, by using current probabilistic procedures. They display the probabilistic estimates of Peak Ground Acceleration (PGA) for the return periods of 75 and 475 years. The maps have been divided into intervals of 0.25 degrees in both latitudinal and longitudinal directions to calculate the peak ground acceleration values at each grid point and draw the seismic hazard curves. The results presented in this study will provide the basis for the preparation of seismic risk maps, the estimation of earthquake insurance premiums, and the preliminary site evaluation of critical facilities.

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.

Evaluation of Peak Ground Acceleration and Response Spectra Considering the Local Site Effects

2010 ◽  
Vol 1 (1) ◽  
pp. 25-41 ◽  
Author(s):  
T. G. Sitharam ◽  
K. S. Vipin
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Site Effects ◽  
Response Spectra ◽  
Probabilistic Logic ◽  
Site Classification ◽  
Ground Acceleration ◽  
Entire Study ◽  
Local Site Effects ◽  
Local Site

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluated for the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work.

Attenuation Function Relationship for Far Field Earthquake Considered by Strike Slip Mechanism

2015 ◽  
Vol 754-755 ◽  
pp. 897-901
Author(s):  
Saffuan Wan Ahmad ◽  
Azlan Adnan ◽  
Rozaimi Mohd Noor ◽  
Khairunisa Muthusamy ◽  
Sk Muiz Sk Razak ◽  
...  
Keyword(s):  
Peak Ground Acceleration ◽  
Strike Slip ◽  
Far Field ◽  
Attenuation Relationship ◽  
Ground Acceleration ◽  
Slip Mechanism ◽  
Earthquake Sources ◽  
Peak Ground Accelerations ◽  
Function Relationship ◽  
The Relationship

An attenuation relationship for far field earthquakes considered by strike slip has been developed. The attenuation relationship function was develop using regression analysis. The database consisting of more than 130 peak ground accelerations from seven earthquake sources recorded by Seismology Station in Malaysia have been used to develop the relationship. This study aims to investigate the new relationship attenuation to gain exact peak ground acceleration at the location on site. Based on this study, the location is a structure located at Terengganu seaside.

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.

Estimation of Peak Ground Acceleration and Its Uncertainty for Northern Indian Region

2011 ◽  
Vol 2 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Girish Chandra Joshi ◽  
Mukat Lal Sharma
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Indian Region ◽  
Branch Points ◽  
Logic Tree ◽  
Ground Acceleration ◽  
Source Models ◽  
Hazard Parameters

In the present study the authors evaluate uncertainties in the seismic hazard assessment for the Northern Indian region, based on the probabilistic seismic hazard analysis (PSHA). The newly compiled earthquake data has been treated for the quality, consistency, and homogeneity in a systematic manner to find out the uncertainties in every step of calculations. Based on the geological and tectonic setup, seismicity and other geophysical anomalies, a seismotectonic model of the region has been developed. The seismic hazard parameters are calculated based on giving proper weight to specific region. The peak ground acceleration (PGA) is estimated for various return periods for the Northern Indian region using a logic tree approach. The variation at the input level in terms of the source models and different Ground Motion Prediction Equations (GMPEs) is used. To examine into the effect of source modelling and GMPEs, the Coefficient of Variation (COV) maps have been generated. To encompass the region and for better resolution, the peak ground acceleration (PGA) is estimated at 15 minute intervals. The COV values due to all branch points in the logic tree decrease with distance from the source and conspicuous increase toward fault boundaries are observed.

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