Field comparison of shallow seismic sources

Geophysics ◽  
1986 ◽  
Vol 51 (11) ◽  
pp. 2067-2092 ◽  
Author(s):  
R. D. Miller ◽  
S. E. Pullan ◽  
J. S. Waldner ◽  
F. P. Haeni
Keyword(s):  
Water Table ◽  
Seismic Source ◽  
Single Site ◽  
Seismic Sources ◽  
Shallow Seismic ◽  
Site Characteristics ◽  
Amplitude Spectra ◽  
Different Characteristics ◽  
Magnitude Difference ◽  
Selection Of

Choosing a seismic source for a shallow reflection survey can be the most pivotal decision for the engineering geophysicist. The intent of this paper is to present data that will assist in selection of a shallow seismic source best meeting the goals within the constraints of specific projects, particularly in areas where the water table is near the surface. The data were collected (and displayed as seismograms and amplitude spectra) for 15 different shallow seismic sources in October, 1985, at a single site in New Jersey; they show the different characteristics of each source. Considering the almost three orders of magnitude difference in total source energy between the largest and smallest source, we chose a display format that presented the data as objectively as possible, while still allowing direct source‐to‐source comparisons. Two strong reflections at about 100 and 130 ms probably mark the top and bottom of a clay unit 80 m below the surface at this site. Our previous work and that of our colleagues suggests that, given a specific set of site characteristics, any source could dominate the comparison categories addressed here.

scholarly journals Field comparison of shallow seismic sources near Chino, California

Geophysics ◽  
1992 ◽  
Vol 57 (5) ◽  
pp. 693-709 ◽  
Author(s):  
Richard D. Miller ◽  
Susan E. Pullan ◽  
Don W. Steeples ◽  
James A. Hunter
Keyword(s):  
Water Table ◽  
Seismic Source ◽  
Test Site ◽  
Single Site ◽  
Seismic Sources ◽  
Near Surface ◽  
Shallow Seismic ◽  
Site Characteristics ◽  
Weight Drop ◽  
Different Sources

Data from a shallow seismic‐source comparison test conducted in an area with a water‐table depth in excess of 30 m and near‐surface velocities less than 330 m/s were acquired from 13 different sources at a single site near Chino, California. The sources included sledgehammer, explosives, weight drop, projectile impacts, and various buffalo guns. A possible reflecting event can be interpreted at about 70 ms. At this particular test site, the lowly sledgehammer is among the best sources to provide data to see the possible reflection. Our previous work and that of our colleagues suggests that any source could dominate the comparison categories addressed here, given the appropriate set of site characteristics.

scholarly journals Field comparison of shallow P‐wave seismic sources near Houston, Texas

Geophysics ◽  
1994 ◽  
Vol 59 (11) ◽  
pp. 1713-1728 ◽  
Author(s):  
Richard D. Miller ◽  
Susan E. Pullan ◽  
Don W. Steeples ◽  
James A. Hunter
Keyword(s):  
Water Table ◽  
Seismic Source ◽  
Dominant Frequency ◽  
P Wave ◽  
Near Surface ◽  
Site Characteristics ◽  
Water Well ◽  
Local Water ◽  
A Site ◽  
Different Sources

A shallow P‐wave seismic source comparison was conducted at a site near Houston, Texas where the depth to the water table was approximately 7 m, and near‐surface materials consisted of clays, sands, and gravels. Data from twelve different sources during this November 1991 comparison are displayed and analyzed. Reflection events are interpretable at about 40 ms on some 220-Hz analog low‐cut filtered field files, and at 60 ms on most 110‐ and 220-Hz analog low‐cut filtered field files. Calculations and local water well information suggest the 40-ms event is from the top of the water table. Subsurface explosive sources seem to possess the highest dominant frequency, broadest bandwidth, and recorded amplitudes and, therefore, have the greatest resolution potential at this site. Our previous work and that of our colleagues suggests that, given a specific set of site characteristics, any source could dominate the comparison categories addressed here.

scholarly journals The Impact of Site Characteristics on the Development of Wind Turbines, as Sources of Recoverable Energy

2013 ◽  
Vol 8-9 ◽  
pp. 157-164
Author(s):  
Dana Madalina Pohrib ◽  
Anghel Stanciu ◽  
Irina Lungu
Keyword(s):  
Slope Stability ◽  
Wind Turbines ◽  
Pile Foundations ◽  
Temperature Variations ◽  
Site Characteristics ◽  
Different Characteristics ◽  
The Impact ◽  
Pile Length ◽  
Recoverable Energy ◽  
Selection Of

For the design of wind turbines it is necessary to consider several conditions such as: wind, turbulence, temperature variations, geology and characteristics of foundation soils on site, earthquake and neighborhood restrictions. The selection of the types and dimensions of the wind turbines foundations are dependent on the geotechnical conditions, the maximum power of turbines and the type of tower. This paper presents various tower structures correlated with the corresponding types of foundations currently used for wind turbines. For this research, the authors performed a variety of analyses and studies involving different characteristics of the locations for the wind turbines. The research shows the solutions obtained for the pile foundations and their impact upon the environment. The paper points out the influence of the pile length on the slope stability as resulted for the soil stratification from the investigated locations.

A noninvasive shallow seismic source comparison on the Oak Ridge Reservation, Tennessee

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1318-1331 ◽  
Author(s):  
William E. Doll ◽  
Richard D. Miller ◽  
Jianghai Xia
Keyword(s):  
Seismic Reflection ◽  
Ground Surface ◽  
Seismic Source ◽  
Seismic Profile ◽  
Seismic Sources ◽  
Waste Site ◽  
Oak Ridge ◽  
Shallow Seismic ◽  
Wave Generator ◽  
Seismic Reflection Profiling

Nine seismic sources were compared in preparation for production seismic reflection profiling to about 500 m depth at a hazardous waste site on the Oak Ridge Reservation, Tennessee. Test data provided a 125-shotpoint common midpoint profile and a walkaway vertical seismic profile for each source. Sources tested included five swept sources and four impulsive sources. Eight of the sources were “noninvasive,” in that they would not penetrate the ground surface. When spectral whitening methods were applied to the data, the IVI Minivib provided the best image of the subsurface on the basis of continuity and clarity of reflections. Without prewhitening, the performance of the IVI Minivib and the Bison elastic wave generator were similar.

A Steganalytic Scheme Based on Classifier Selection Using Joint Image Characteristics

2020 ◽  
pp. 362-376
Author(s):  
Jie Zhu ◽  
Qingxiao Guan ◽  
Xianfeng Zhao ◽  
Yun Cao ◽  
Gong Chen
Keyword(s):  
Image Size ◽  
Size Quantization ◽  
Classification Techniques ◽  
Appreciable Difference ◽  
Classifier Selection ◽  
Image Characteristics ◽  
Improve Accuracy ◽  
Different Characteristics ◽  
Selection Of

Steganalysis relies on steganalytic features and classification techniques. Because of the complexity and different characteristics of cover images, to make steganalysis more applicable toward detecting stego images in real applications, we need to train different classifiers so as to match different images according to their characteristics. Selection of classifiers according to characteristics of images is the key point to improve accuracy of steganalysis. In our work, we study the methods of classifier selection based on characteristics of images including image size, quantization factor, or matrix. Besides, we also discuss other characteristics, such as texture, cover source, which makes an appreciable difference to steganalysis.

scholarly journals Numerical Evaluation on Analysis Methods of Trapping Site Density in Steels Based on Hydrogen Permeation Curve

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3712
Author(s):  
Bangshu Yang ◽  
Li Li ◽  
Lin Cheng
Keyword(s):  
Hydrogen Permeation ◽  
Effective Diffusivity ◽  
Trapping Site ◽  
Hydrogen Trapping ◽  
Site Density ◽  
Site Characteristics ◽  
Inappropriate Utilization ◽  
Magnitude Difference ◽  
Trapping Sites ◽  
Permeation Test

Hydrogen permeation techniques have been widely utilized to extract hydrogen effective diffusivity, as well as hydrogen trapping site characteristics in steels. Several methods have been proposed to examine reversible and irreversible trapping site characteristics. However, the inappropriate utilization of these simplified models, as well as incorrect value assignment to the key parameters, can result in several orders of magnitude difference in hydrogen trapping site density. Therefore, in order to evaluate these models and verify their application prerequisites, a serial of hydrogen permeation tests were numerically simulated and examined, separately considering reversible and irreversible hydrogen trapping sites. In the meantime, suggestions were given to conduct hydrogen permeation test more effectively, and evaluate hydrogen trapping site characteristics more precisely.

Pounce site characteristics of the Western Yellow Robin Eopsaltria griseogularis: the importance of assessing foraging microhabitat

2004 ◽  
Vol 10 (1) ◽  
pp. 21 ◽  
Author(s):  
Jarrad a. Cousin
Keyword(s):  
Leaf Litter ◽  
Substrate Composition ◽  
Habitat Features ◽  
Invertebrate Prey ◽  
Conservation Implications ◽  
Site Characteristics ◽  
Australian Birds ◽  
Close Proximity ◽  
Selection Of

The ground ecosystem represents an important foraging substrate for a large number of Australian birds, including the ground-pouncing Western Yellow Robin Eopsaltria griseogulari. The present study examined the foraging locations of E. griseogularis at the "extreme" microhabitat scale, by measuring ground substrate composition in a 300 mm by 300 mm area surrounding pounce sites, as well as habitat features surrounding pounce sites. Ground substrate composition of pounce sites remained relatively unchanged between seasons, and was characterized by a higher mean percentage of leaf litter and logs when compared to random points. The importance of logs was further emphasized by the closer proximity of logs to pounce sites than to random points. Selection of pounce sites in close proximity to logs and with abundant leaf litter reflects the higher abundance of invertebrate prey associated with these microhabitat attributes, although it may also represent a pounce in close proximity to a log utilized as a perch. During the warmer months of autumn, logs and their associated accumulations of leaf litter, provide sufficient moisture to maintain invertebrate prey, a resource diminished in the surrounding desiccated leaf litter. The conservation implications of these findings are discussed, as is the importance of examining foraging microhabitat in ground-foraging birds.

A Time–Frequency Representation Model for Seismic Ground Motions

2020 ◽  
Author(s):  
Xi Zhong Cui ◽  
Han Ping Hong
Keyword(s):  
Ground Motions ◽  
Seismic Source ◽  
Model Parameters ◽  
Time Frequency ◽  
Motion Models ◽  
Power Spectral ◽  
Frequency Representation ◽  
Site Characteristics ◽  
S Transform ◽  
Proposed Model

ABSTRACT A probabilistic model of the time–frequency power spectral density (TFPSD) is presented. The model is developed, based on the time–frequency representation of records from strike-slip earthquakes, in which the time–frequency representation is obtained by applying the S-transform (ST). The model for the TFPSD implicitly considers the amplitude modulation and frequency modulation for the nonstationary ground motions; this differs from the commonly used evolutionary PSD model. Predicting models for the model parameters, based on seismic source and site characteristics, are developed. The use of the model to simulate ground motions for scenario seismic events is illustrated, in which the simulation is carried out using a recently developed model that is based on the discrete orthonormal ST and ST. The illustrative example highlights the simplicity of using the proposed model and the physical meaning of some of the model parameters. A model validation analysis is carried out by comparing the statistics of the pseudospectral acceleration obtained from the simulated records to those obtained using a few ground-motion models available in the literature and considered actual records. The comparison indicates the adequacy of the proposed model.

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