Preliminary empirical model for scaling fourier amplitude spectra of strong ground acceleration in terms of modified mercalli intensity and recording site conditions

1979 ◽  
Vol 7 (1) ◽  
pp. 63-74 ◽  
Author(s):  
M. D. Trifunac
Keyword(s):  
Empirical Model ◽  
Site Conditions ◽  
Fourier Amplitude ◽  
Recording Site ◽  
Ground Acceleration ◽  
Amplitude Spectra ◽  
Strong Ground

scholarly journals Preliminary empirical model for scaling Fourier Amplitude Spectra of strong ground acceleration in terms of earthquake magnitude, source-to-station distance, and recording site conditions

1976 ◽  
Vol 66 (4) ◽  
pp. 1343-1373 ◽  
Author(s):  
M. D. Trifunac
Keyword(s):  
Empirical Model ◽  
Fourier Spectrum ◽  
Epicentral Distance ◽  
Site Conditions ◽  
Fourier Amplitude ◽  
Recording Site ◽  
Ground Acceleration ◽  
Amplitude Spectra ◽  
Order Of Magnitude ◽  
Strong Ground

abstract An empirical model for scaling Fourier Amplitude Spectra of strong earthquake ground acceleration in terms of magnitude, M, epicentral distance, R, and recording site conditions has been presented. The analysis based on this model implies that: It has been shown that the uncertainties which are associated with the forecasting of Fourier amplitude spectra in terms of magnitude, epicentral distance, site conditions, and component direction are considerable and lead to the range of spectral amplitudes which for an 80 per cent confidence interval exceed one order of magnitude. A model has been presented which empirically approximates the distribution of Fourier spectrum amplitudes and enables one to estimate the spectral shapes which are not exceeded by the presently available data more than 100 (1 - p) per cent of time where p represents the desired confidence level (0 < p <1).

Spectral characteristics of central Nevada microearthquakes

1970 ◽  
Vol 60 (5) ◽  
pp. 1547-1559 ◽  
Author(s):  
Bruce M. Douglas ◽  
Alan Ryall ◽  
Ray Williams
Keyword(s):  
Spectral Characteristics ◽  
Propagation Path ◽  
Seismic Signals ◽  
Fourier Amplitude ◽  
Recording Site ◽  
Focal Distance ◽  
Amplitude Spectra ◽  
Spectral Frequency ◽  
Group Characteristics ◽  
Event Magnitude

Abstract Fourier amplitude spectra were computed for 40 central Nevada microearthquakes, selected to consider, independently, effects of azimuth and distance from known sources. Spectra were averaged for groups of events to eliminate peculiarities of individual records and emphasize group characteristics. Spectral characteristics did not behave systematically as a function of azimuth from the recording site to the source, but peak spectral frequency was found to correlate strongly with event magnitude and to some degree also with focal distance. These preliminary results suggest that recordings of small earthquakes and microearthquakes can be used to provide detailed information on the character of seismic signals related to properties of the source and propagation path.

On the Correlation of Seismic Intensity with Fourier Amplitude Spectra

1998 ◽  
Vol 14 (4) ◽  
pp. 679-694 ◽  
Author(s):  
V. Yu Sokolov ◽  
Yu K. Chernov
Keyword(s):  
Seismic Waves ◽  
Distribution Patterns ◽  
Seismic Intensity ◽  
Earthquake Ground Motion ◽  
Intensity Level ◽  
Fourier Amplitude ◽  
Ground Acceleration ◽  
Amplitude Spectra ◽  
Narrow Frequency Band ◽  
Recent Earthquakes

This paper presents a method for estimating the seismic intensity (MMI or MSK scale) using Fourier amplitude spectra of ground acceleration. The method implies that the severity of earthquake ground motion is determined by spectral amplitudes in a relatively narrow frequency band: so-called “representative frequencies”, at decreasing frequencies (from 7-8 Hz for small intensities to 0.7-1.0 Hz for MMI=VIII-IX) with increasing intensity level. It is examined through estimation of probable intensity at a site using recordings of recent earthquakes in several seismic regions, and prediction of intensity distribution patterns for the Coalinga, California earthquake of May 2, 1983, and the Spitak, Armenia earthquake of December 7, 1988. Seismic hazard maps, in terms of intensity levels based upon the proposed approach, should describe regional features of seismic waves excitation and propagation, as well as local ground conditions.

scholarly journals Response spectra of trains to earthquakes

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Ekaterina Pestriakova ◽  
Evgeny Kurbatskiy ◽  
Trong Tam Nguyen
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Fourier Spectrum ◽  
Response Spectra ◽  
Rolling Stock ◽  
Research Assessment ◽  
Fourier Amplitude ◽  
Ground Acceleration ◽  
Amplitude Spectra ◽  
Fourier Spectra

Currently, the construction of railways for high-speed traffic is developing intensively. Overcoming water obstacles is carried out by the construction of artificial structures such as bridges and tunnels. It often becomes necessary to cross areas with increased seismic activity by rail lines. Which, in turn, increases the likelihood of crews on bridges and in tunnels during earthquakes. With adverse combinations of dynamic parameters during earthquakes, fluctuations may occur that threaten the safety of movement. In this regard, it is necessary to evaluate the response of rolling stock to the effects of this kind. Vertical and horizontal oscillations of rolling stock during earthquakes can reach large quantities, which is fraught with serious consequences. Dynamic characteristics of locomotives and cars have significant differences. Locomotives and wagons can be of different brands, in addition, wagons can be empty and loaded. The parameters of earthquakes that can occur in a given area can also be diverse. To solve such a complex task, the authors of the article use the widely used abroad concept of response spectra, which allows to evaluate the response of objects with different natural frequencies to all possible earthquakes. The amplitude Fourier spectra and the spectra of the maximum reactions at speeds have the same dimensions. There is a relationship between these functions, which is used to construct response spectra if the amplitude Fourier spectrum of the ground acceleration function is known. Therefore, to construct the response spectra of the crews for earthquakes, the Fourier amplitude spectra of the base oscillations were used as the initial data. The results presented in the article are part of the dissertation research «Assessment of the dynamic effects of railway and natural origin on underwater tunnels» Pestryakova E.A.

A frequency-dependent ground-motion spatial correlation model of within-event residuals for Fourier amplitude spectra

2021 ◽  
pp. 875529302098199
Author(s):  
Nan Wang ◽  
Kim B Olsen ◽  
Steven M Day
Keyword(s):  
Time Series ◽  
Spatial Correlation ◽  
Ground Motion ◽  
Empirical Model ◽  
Correlation Model ◽  
Motion Generation ◽  
Fourier Amplitude ◽  
Frequency Dependent ◽  
Spatial Correlation Structure ◽  
Amplitude Spectra

Ground motion time series recorded at stations separated by up to about 50 km show a frequency-dependent spatial coherency structure, and the corresponding ground motion intensity measures are found to be correlated. As omitting this correlation can result in underestimation of seismic losses in risk analysis, it is critical to quantify the spatial correlation structure for ground motion Fourier spectra estimated at different sites during a single event within a region. Toward this goal, we have developed an empirical frequency-dependent spatial correlation model for the within-event residuals of effective Fourier amplitude spectra from the Pacific Earthquake Engineering Research Center (PEER) Next Generation Attenuation (NGA) West2 database. The correlation model shows slower decrease of the spatial correlation with distance at lower frequencies compared with higher frequencies, in agreement with the underlying ground motion data, and no significant dependence on the magnitude of the earthquakes is observed. We use this empirical model to incorporate frequency-dependent spatial correlation into a hybrid deterministic-stochastic broadband ground motion generation module, which successfully generates synthetic time series for seven western US earthquakes with frequency-dependent spatial correlation that closely mimics that of the empirical model. Furthermore, the method also significantly improves the correlation for spectral accelerations, cumulative absolute velocities, and Arias intensities, compared with that derived from the original broadband module.

scholarly journals Modelling of speleothems failure in the Hotton cave (Belgium). Is the failure earthquake induced?

2001 ◽  
Vol 80 (3-4) ◽  
pp. 315-321 ◽  
Author(s):  
J.F. Cadorin ◽  
D. Jongmans ◽  
A. Plumier ◽  
T. Camelbeeck ◽  
S. Delaby ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Quantitative Information ◽  
Rigid Bodies ◽  
Tensile Failure ◽  
Future Research ◽  
Geometrical Parameters ◽  
Laboratory Measurements ◽  
Ground Acceleration ◽  
Strong Ground

AbstractTo provide quantitative information on the ground acceleration necessary to break speleothems, laboratory measurements on samples of stalagmite have been performed to study their failure in bending. Due to their high natural frequencies, speleothems can be considered as rigid bodies to seismic strong ground motion. Using this simple hypothesis and the determined mechanical properties (a minimum value of 0.4 MPa for the tensile failure stress has been considered), modelling indicates that horizontal acceleration ranging from 0.3 m/s2 to 100 m/s2 (0.03 to 10g) are necessary to break 35 broken speleothems of the Hotton cave for which the geometrical parameters have been determined. Thus, at the present time, a strong discrepancy exists between the peak accelerations observed during earthquakes and most of the calculated values necessary to break speleothems. One of the future research efforts will be to understand the reasons of the defined behaviour. It appears fundamental to perform measurements on in situ speleothems.

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