scholarly journals Variations between Foundation-Level and Free-Field Earthquake Ground Motions

2000 ◽  
Vol 16 (2) ◽  
pp. 511-532 ◽  
Author(s):  
Jonathan P. Stewart
Keyword(s):  
Free Field ◽  
Low Frequency ◽  
Strong Motion ◽  
Dimensionless Frequency ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Ground Motion Selection ◽  
Motion Data ◽  
Embedded Foundations

Strong motion data from sites having both an instrumented structure and free-field accelerograph are compiled to evaluate the conditions for which foundation recordings provide a reasonably unbiased estimate of free-field motion with minimal uncertainty. Variations between foundation and free-field spectral acceleration are found to correlate well with dimensionless parameters that strongly influence kinematic and inertial soil-structure interaction phenomena such as embedement ratio, dimensionless frequency (i.e., product of radial frequency and foundation radius normalized by soil shear wave velocity), and ratio of structure-to-soil stiffness. Low frequency components of spectral acceleration recorded on shallowly embedded foundations are found to provide good estimates of free-field motion. In contrast, foundation-level peak ground acceleration (both horizontal and vertical) and maximum horizontal velocity, are found to be de-amplified. Implications for ground motion selection procedures employed in attenuation relations are discussed, and specific recommendations are made as to how these procedures could be improved.

Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 imperial valley, California, earthquake

1981 ◽  
Vol 71 (6) ◽  
pp. 2011-2038 ◽  
Author(s):  
William B. Joyner ◽  
David M. Boore
Keyword(s):  
Strong Motion ◽  
Fault Rupture ◽  
Imperial Valley ◽  
Attenuation Relations ◽  
Motion Data ◽  
Horizontal Acceleration ◽  
Anelastic Attenuation ◽  
Distance Dependence ◽  
Peak Horizontal Acceleration

Abstract We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence. The resulting equations are log A = − 1.02 + 0.249 M − log r − 0.00255 r + 0.26 P r = ( d 2 + 7.3 2 ) 1 / 2 5.0 ≦ M ≦ 7.7 log V = − 0.67 + 0.489 M − log r − 0.00256 r + 0.17 S + 0.22 P r = ( d 2 + 4.0 2 ) 1 / 2 5.3 ≦ M ≦ 7.4 where A is peak horizontal acceleration in g, V is peak horizontal velocity in cm/ sec, M is moment magnitude, d is the closest distance to the surface projection of the fault rupture in km, S takes on the value of zero at rock sites and one at soil sites, and P is zero for 50 percentile values and one for 84 percentile values. We considered a magnitude-dependent shape, but we find no basis for it in the data; we have adopted the magnitude-independent shape because it requires fewer parameters.

Seismic Response of Embankment Dams Based on Recorded Strong-Motion Data in Japan

2019 ◽  
Vol 35 (2) ◽  
pp. 955-976 ◽  
Author(s):  
DongSoon Park ◽  
Tadahiro Kishida
Keyword(s):  
Time Series ◽  
Seismic Response ◽  
Prediction Models ◽  
Strong Motion ◽  
Dynamic Responses ◽  
Design Stage ◽  
Ground Acceleration ◽  
Motion Data ◽  
Embankment Dams ◽  
Strong Motion Database

It is important to investigate strong-motion time series recorded at dams to understand their complex seismic responses. This paper develops a strong-motion database recorded at existing embankment dams and analyzes correlations between dam dynamic responses and ground-motion parameters. The Japan Commission on Large Dams database used here includes 190 recordings at the crests and foundations of 60 dams during 54 earthquakes from 1978 to 2012. Seismic amplifications and fundamental periods from recorded time series were computed and examined by correlation with shaking intensities and dam geometries. The peak ground acceleration (PGA) at the dam crest increases as the PGA at the foundation bedrock increases, but their ratio gradually decreases. The fundamental period broadly increases with the dam height and PGA at the foundation bedrock. The nonlinear dam response becomes more apparent as the PGA at the foundation bedrock becomes >0.2 g. The prediction models of these correlations are proposed for estimating the seismic response of embankment dams, which can inform the preliminary design stage.

Strong-Motion Data from Structural Response Recorders in Indian Earthquakes

2012 ◽  
Vol 28 (1) ◽  
pp. 77-103 ◽  
Author(s):  
Sudhir K. Jain ◽  
A. D. Roshan ◽  
Siddharth Yadav ◽  
Sonam Srivastava ◽  
Prabir C. Basu
Keyword(s):  
Peak Ground Acceleration ◽  
Structural Response ◽  
Time History ◽  
Strong Motion ◽  
Ground Acceleration ◽  
Motion Data ◽  
The Past ◽  
Simple Instrument ◽  
Low Costs ◽  
The 1960S

In the 1960s several hundred structural response recorders (SRR) were installed all over India. An SRR is a simple instrument consisting of six seismoscopes that provide “maximum response” during an earthquake, without providing the time history. In the past earthquakes, these SRRs have provided several hundred records but they have not been effectively utilized for hazard studies because the measurements from these instruments are considered crude. This paper compares the data obtained from SRRs with that from more modern strong-motion accelerographs (SMAs) for four earthquakes in India. It is shown through statistical analysis that the response obtained from the SRRs is comparable to that from the SMAs. A method has been presented for estimating peak ground acceleration (PGA) from SRR data. Thus, it is shown that SRRs can provide a substantial amount of PGA data for attenuation studies. Many countries may find SRRs useful because of the low costs associated with their manufacture and maintenance.

scholarly journals Uncertainties in attenuation relations for New Zealand seismic hazard analysis

1986 ◽  
Vol 19 (1) ◽  
pp. 28-39 ◽  
Author(s):  
G. H. McVerry
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Response Spectrum ◽  
Strong Motion ◽  
Seismic Hazard Analysis ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Ground Shaking ◽  
Acceleration Data

Probabilistic techniques for seismic hazard analysis have
come into vogue in New Zealand for both the assessment of major projects and the development and review of seismic design codes. However, there are considerable uncertainties in the modelling
 of the strong-motion attenuation, which is necessarily based largely on overseas data. An excellent agreement is obtained between an average 5% damped response spectrum for New Zealand alluvial sites in the 20 to 59 km distance range and 5.4 to 6.0 magnitude class and that given by a Japanese model. Unfortunately, this corresponds to only about half the amplitude levels of 150 year spectra relevant to code design. The much more rapid decay
of ground shaking with distance in New Zealand has led to a considerable modification based on maximum ground acceleration
data from the Inangahua earthquake of the distance-dependence
of the Japanese response spectra model. Less scatter in New Zealand data has resulted in adopting a lower standard deviation for the attenuation model, which is important in reducing the considerable "probabilistic enhancement" of the hazard estimates. Regional differences in attenuation shown by intensities are difficult to resolve from the strong-motion acceleration data, apart from lower accelerations in Fiordland.

scholarly journals Strong motion data centre

1971 ◽  
Vol 4 (1) ◽  
pp. 15-30
Author(s):  
D. Denham ◽  
G. R. Small
Keyword(s):  
Volcanic Ash ◽  
Strong Motion ◽  
Mineral Resources ◽  
Australian Bureau ◽  
Ground Acceleration ◽  
Strong Motion Data ◽  
Motion Data ◽  
Data Centre ◽  
Unconsolidated Material ◽  
Storage Distribution

A Strong Motion Data Centre, for the collection, storage, distribution and preliminary analysis of accelerograms from the Australian and New Guinean regions, has recently been established at Canberra by the Australian Bureau of Mineral Resources. The work undertaken at the Centre is described and examples of the processing facilities available are given. Extensive use is made of computers in the analysis of the accelerograms and the plotting of the results. By December 1970 thirteen accelerographs had been obtained, by several institutions, for installation in the Australian and New Guinea regions and 24 accelerograms had been received at the Centre for analysis. The instruments located on unconsolidated material at Lae, Yonki and Panguna are currently producing about 5 accelerograms per year and the maximum ground acceleration recorded so far, of 0.12g, was obtained at Panguna, where the accelerograph is located on recent unconsolidated volcanic ash.

Estimation of attenuation relations for strong-motion data allowing for individual earthquake magnitude uncertainties

1997 ◽  
Vol 87 (6) ◽  
pp. 1674-1678
Author(s):  
David A. Rhoades
Keyword(s):  
Ground Motion ◽  
Regression Models ◽  
Strong Ground Motion ◽  
Strong Motion ◽  
Error Variance ◽  
Attenuation Relations ◽  
Motion Data ◽  
Different Levels ◽  
Magnitude Determination ◽  
Strong Ground

Abstract Standard errors of earthquake magnitudes are routinely calculated and vary appreciably between earthquakes. However, the uncertainties of magnitude determination are usually ignored in regression models of strong ground motion as a function of magnitude and distance from the earthquake source. This practice has the potential to bias estimates of strong ground motion. A method is given for taking account of the uncertainty of each magnitude determination in fitting such models. It extends previous methods in which the error variance is partitioned into between-earthquake and within-earthquake components. It allows for further decomposition of the between-earthquake component into a part attributable to magnitude uncertainties and a part attributable to other causes. The method has been applied to the well-known attenuation data of Joyner and Boore (1981). The Mw determinations in this dataset fall into two subsets with distinctly different levels of precision, namely, those determined directly and those inferred from values of ML. It is shown that most of the between-earthquake component of variance can be attributed to the relatively low precision of the magnitudes in the latter subset.

scholarly journals Implications of the Observed Seismic Performance of a Pile-Supported Wharf for Numerical Modeling

2005 ◽  
Vol 21 (3) ◽  
pp. 617-634 ◽  
Author(s):  
Matthew J. Donahue ◽  
Stephen E. Dickenson ◽  
Thomas H. Miller ◽  
Solomon C. Yim
Keyword(s):  
Structural Model ◽  
Seismic Analysis ◽  
Free Field ◽  
Strong Motion ◽  
Sloping Ground ◽  
Loma Prieta Earthquake ◽  
Structure Interaction ◽  
Motion Data ◽  
And Performance ◽  
Recent Earthquakes

The seismic response and performance of pile-supported wharves on sloping ground is not well documented due to an historical lack of instrumentation on port structures. Although general surface observations have been made at numerous ports following recent earthquakes, much more specific soil foundation-structure-interaction data could have been obtained with the more widespread employment of instrumentation. This paper presents the results of empirical and numerical analyses of recorded strong-motion data (SMD) from an array of instruments located on a pile-supported wharf and in the adjacent free field. Data were recorded with an instrumentation array at Berth 24/25 at the Port of Oakland, California, during the M7.0 Loma Prieta earthquake. The primary objectives of this project were to evaluate the SMD and identify the limitations inherent in capturing the complete dynamic character, including soil structure interaction, of a pier or wharf with a structural model. The project is expected to serve the professional engineering community by providing guidance in selecting appropriate techniques for seismic analysis and subsequent upgrade of existing port facilities.

Maximum Likelihood Estimation of Strong-Motion Attenuation Relationships

1991 ◽  
Vol 7 (2) ◽  
pp. 267-279 ◽  
Author(s):  
K. L. McLaughlin
Keyword(s):  
Maximum Likelihood ◽  
Strong Motion ◽  
Likelihood Estimation ◽  
Earthquake Ground Motion ◽  
Attenuation Relation ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Attenuation Relationships ◽  
The Mean ◽  
Data Censoring

Strong-motion attenuation relations are commonly derived from earthquake ground motion collected on triggered recorders. Parametric attenuation relations are estimated from these data using standard least squares methods. The variance of ground acceleration is relatively large and for any given earthquake, there is a distance range for which only stations with larger than average amplitudes will trigger recording. Consequently observed accelerations at these distances are higher than the mean ground acceleration and a bias may be introduced into an attenuation relation regression by non-detection data censoring.

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