scholarly journals Stochastic Simulation of Ground Motions Generated by Vrancea Intermediate-Depth Seismic Source

2018 ◽  
Vol 1 (2) ◽  
pp. 27-32 ◽  
Author(s):  
Anabella Coțovanu ◽  
Keyword(s):  
Stochastic Simulation ◽  
Ground Motions ◽  
Seismic Source ◽  
Intermediate Depth

Estimation of Ground Motions in the Valley of Mexico from Normal-Faulting, Intermediate-Depth Earthquakes in the Subducted Cocos Plate

1995 ◽  
Vol 11 (2) ◽  
pp. 233-247 ◽  
Author(s):  
Javier F. Pacheco ◽  
Shri Krishna Singh
Keyword(s):  
Seismic Waves ◽  
Ground Motions ◽  
Seismic Source ◽  
Source Model ◽  
Normal Faulting ◽  
Cocos Plate ◽  
Intermediate Depth ◽  
S Waves ◽  
Local Site ◽  
Seismic Source Model

The Valley of Mexico is exposed to seismic risk from normal-faulting, large intermediate-depth earthquakes. We explore two approaches to estimate future ground motions from such events at CU, a hill-zone site in the valley. In the first we obtain parameters of an ω2 seismic source model and determine amplification of seismic waves due to local site effects at CU. This permits estimation of Fourier spectrum of expected ground motion at CU from postulated earthquakes. We find that the S-waves suffer an amplification of 2.5 between 0.2 to 3.0 Hz. This amplification is similar to that observed from deep teleseismic events but differs from that obtained from shallow coastal events. In the second approach the available recordings at CU are used as empirical Green's functions (EGF) to synthesize motions from future large earthquakes. This approach is very powerful if the smaller event is truly an empirical Green's function for the postulated earthquake.

Proposed methodology for estimating the magnitude at which subduction megathrust ground motions and source dimensions exhibit a break in magnitude scaling: Example for 79 global subduction zones

2020 ◽  
Vol 36 (3) ◽  
pp. 1271-1297
Author(s):  
Kenneth W. Campbell
Keyword(s):  
Ground Motion ◽  
Subduction Zones ◽  
Ground Motions ◽  
Seismic Source ◽  
Scaling Relations ◽  
Megathrust Earthquakes ◽  
Source Dimensions ◽  
Magnitude Scaling ◽  
Aspect Ratios ◽  
Source Scaling

In this article, I propose a method for estimating the magnitude [Formula: see text] at which subduction megathrust earthquakes are expected to exhibit a break in magnitude scaling of both seismic source dimensions and earthquake ground motions. The methodology is demonstrated by applying it to 79 global subduction zones defined in the literature, including Cascadia. Breakpoint magnitude is estimated from seismogenic interface widths, empirical source scaling relations, and aspect ratios of physically unbounded earthquake ruptures and their uncertainties. The concept stems from the well-established observation that source-dimension and ground motion scaling decreases for shallow continental (primarily strike-slip) earthquakes when rupture exceeds the seismogenic width of the fault. Although a scaling break for megathrust earthquakes is difficult to observe empirically, all of the instrumentally recorded historical [Formula: see text] mega-earthquakes have occurred on subduction zones with [Formula: see text] (8.1–8.9), consistent with an observed break in source scaling relations derived from these same events. The breakpoint magnitudes derived in this study can be used to constrain the magnitude at which the scaling of ground motion is expected to decrease in subduction ground motion prediction equations.

Estimating the accuracy of source “parameters”

1967 ◽  
Vol 57 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Helen W. Freedman
Keyword(s):  
Standard Error ◽  
Source Parameters ◽  
Seismic Source ◽  
Origin Time ◽  
Intermediate Depth ◽  
Seismic Source Parameters ◽  
Space And Time

abstract This paper suggests a method for estimating the errors accompanying estimates of seismic source parameters. While the method is a general one, the data here are from 1962 and 1963 and special attention is given to a few regions, such as the Kuriles. The overall standard error of about one-half a degree in each coordinate and four seconds in origin time are broken down and analyzed in terms of magnitude, depth, and location in space and time. The most accurately located earthquakes appear to be those of intermediate depth and magnitude in highly seismic areas. There is some indication that these errors are decreasing with time.

A Stochastic Semi-Physical Model of Seismic Ground Motions in Time Domain

2018 ◽  
Vol 12 (03) ◽  
pp. 1850006 ◽  
Author(s):  
Yanqiong Ding ◽  
Yongbo Peng ◽  
Jie Li
Keyword(s):  
Probability Density ◽  
Ground Motions ◽  
Seismic Source ◽  
Response Spectra ◽  
Propagation Path ◽  
Superposition Method ◽  
Probability Density Evolution Method ◽  
Proposed Model ◽  
Time Histories ◽  
Seismic Accelerations

A stochastic function model of seismic ground motions is presented in this paper. It is derived from the consideration of physical mechanisms of seismic ground motions. The model includes the randomness inherent in the seismic source, propagation path and local site. For logical selection of the seismic acceleration records, a cluster analysis method is employed. Statistical distributions of the random parameters associated with the proposed model are identified using the selected data. Superposition method of narrow-band wave groups is then adopted to simulate non-stationary seismic ground motions. In order to verify the feasibility of the proposed model, comparative studies of time histories and response spectra of the simulated seismic accelerations against those of the recorded seismic accelerations are carried out. Their probability density functions, moreover, are readily investigated by virtue of the probability density evolution method.

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