Energy spectra for underground explosions and earthquakes

1963 ◽  
Vol 53 (5) ◽  
pp. 997-1005
Author(s):  
G. E. Frantti
Keyword(s):  
Energy Density ◽  
Frequency Dependence ◽  
Discrimination Problem ◽  
Seismic Source ◽  
Energy Spectra ◽  
Time Duration ◽  
Source Discrimination ◽  
Earthquake Energy

Abstract Energy density for the entire seismogram is examined as a function of frequency for underground explosions and earthquakes. Anomalous differences in the spectra appear to correlate with the time duration of the source. Ratios of aftershock to earthquake energy show a relatively flat frequency dependence. In contrast, corresponding ratios for nuclear shot-collapse events change rapidly with increasing frequency. Analysis of these data suggests that measurements of total seismogram energy might be usefully applied in the seismic source discrimination problem.

scholarly journals A quasi-monoenergetic short time duration compact proton source for probing high energy density states of matter

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. I. Apiñaniz ◽  
S. Malko ◽  
R. Fedosejevs ◽  
W. Cayzac ◽  
X. Vaisseau ◽  
...  
Keyword(s):  
Energy Density ◽  
Proton Beam ◽  
Dense Matter ◽  
High Energy ◽  
High Repetition Rate ◽  
High Energy Density ◽  
Time Duration ◽  
Ultrashort Pulse Laser ◽  
Proton Source ◽  
Short Time

AbstractWe report on the development of a highly directional, narrow energy band, short time duration proton beam operating at high repetition rate. The protons are generated with an ultrashort-pulse laser interacting with a solid target and converted to a pencil-like narrow-band beam using a compact magnet-based energy selector. We experimentally demonstrate the production of a proton beam with an energy of 500 keV and energy spread well below 10$$\% $$ % , and a pulse duration of 260 ps. The energy loss of this beam is measured in a 2 $$\upmu $$ μ m thick solid Mylar target and found to be in good agreement with the theoretical predictions. The short time duration of the proton pulse makes it particularly well suited for applications involving the probing of highly transient plasma states produced in laser-matter interaction experiments. This proton source is particularly relevant for measurements of the proton stopping power in high energy density plasmas and warm dense matter.

Investigation of turbulent flow field in a Kenics static mixer by Laser Doppler Anemometry

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Halina Murasiewicz ◽  
Zdzislaw Jaworski
Keyword(s):  
Reynolds Number ◽  
Energy Density ◽  
Laser Doppler Anemometry ◽  
Strong Dependence ◽  
Angular Position ◽  
Laser Doppler ◽  
Energy Spectra ◽  
Static Mixer ◽  
Measurement Point ◽  
Velocity Fluctuations

AbstractThe main purpose of the present paper was to apply the Laser Doppler Anemometry (LDA) technique to measure turbulent liquid flow in a Kenics static mixer. The LDA set-up was a one-channel backscatter system with argon-ion laser. Measurements in the static mixer were carried out for three values of the Reynolds number: 5000, 10000, and 18000. Water was used as the process liquid. Values of the axial and tangential components of the local, mean, and root mean square velocities were measured inside the static mixer. It was observed that the shape of the velocity profile depends strongly on the Reynolds number, Re, as well as on the axial, h, and radial, α, position of the measurement point. Strong dependence of the velocity fluctuations on the Reynolds number was found in the investigated range of Re and the measurement point position. Furthermore, one-dimensional energy spectra of the velocity fluctuations were also obtained by means of the Fast Fourier Transform. Fluctuation spectra of the axial and tangential velocities provided information about the energy density of velocity fluctuations in the observed range of Reynolds numbers. A study of the energy spectra led to the conclusion that the energy density increases with the increasing radial distance from the mixer walls at constant values of h, Re, and α. Minor variations in the mean value of the energy density, E, were observed together with variations of the measurement point angular position, α. In addition, it was observed that an increase of the Reynolds number causes significant increase of the power spectral density.

Spectral energy density for quarry explosions

1963 ◽  
Vol 53 (5) ◽  
pp. 989-996 ◽  
Author(s):  
G. E. Frantti
Keyword(s):  
Energy Density ◽  
Seismic Waves ◽  
Energy Levels ◽  
Total Duration ◽  
Seismic Energy ◽  
Body Waves ◽  
Propagation Path ◽  
Spectral Energy ◽  
Time Duration ◽  
Duration Time

Abstract Several explosions of varying time duration have been recorded at 156 km along a constant propagation path from a central Michigan limestone quarry. Energy density for body waves and surface waves is examined as a function of frequency and observed to peak between 1 and 10 cps. A correlation between spectral amplitudes and source duration time is revealed and is emphasized at shot durations which approximate the dominant period of seismic waves. A study of the data suggests that seismic energy levels may be controlled, in part, by regulating the time duration of delayed quarry blasts. This parameter (total duration time) has been generally neglected in published studies involving commercial blasts.

Third Generation Wind Wave Model Frequency Dependence of the White-Capping Dissipation Source Function

2002 ◽  
Author(s):  
Eustorgio Meza ◽  
Jun Zhang ◽  
Alejandro Olivares ◽  
Jorge Brambila
Keyword(s):  
Energy Dissipation ◽  
Energy Density ◽  
Frequency Dependence ◽  
Source Function ◽  
Wind Wave ◽  
Wave Model ◽  
Peak Frequency ◽  
Third Generation ◽  
Empirical Formulas ◽  
Transient Wave

This paper proposes new frequency dependence for the empirical formulas presently used to determine wave energy dissipation in ocean wave models. Using an energy focusing technique, several unidirectional transient wave trains were generated. Each of the transient wave train contained an isolated plunging or spilling breaker. By comparing the energy spectra of free-wave components before and after breaker it was found that: 1)the energy loss as function of frequency is almost exclusively from wave components at frequencies higher than the spectral peak frequency; 2)although the energy density of the wave components near the peak frequency are the largest, they do not significantly gain or lose energy after breaking; and 3)wave components of frequencies significantly below or near the peak frequency gain a small portion (about 12%) of energy lost by the high-frequency waves. The empirical formulas presently used to determine white-capping dissipation (Komen et al. 1994; Tolman and Chalikov 1996; Booij 1999) do not agree with the above spectral distribution of energy dissipation. Analysis of the dissipation distribution obtained by Meza et al. (2000), suggest that the dependence of the dissipation rate on the frequency should be described by, (ωωp)(1−(ωωp)E(ω), where ω is the wave frequency, ωp is the spectral peak frequency and E(ω) is the energy density spectrum. An energy dissipation source function with such a frequency dependence is being implemented and tested in a third generation wind wave model.

scholarly journals WAVE FORCES ON PILES IN RELATION TO WAVE ENERGY SPECTRA

1968 ◽  
Vol 1 (11) ◽  
pp. 61
Author(s):  
A. Paape
Keyword(s):  
Energy Density ◽  
Probability Distribution ◽  
Wave Energy ◽  
Wave Motion ◽  
Irregular Waves ◽  
Energy Spectra ◽  
Wave Forces ◽  
Density Spectrum ◽  
The Waves

The determination of wave forces on piles is for an important part based upon data obtained with regular laboratory waves. Nonlmearities m the mechanism that underlies these forces may lead to deviations when applying the data to predict forces exerted by irregular waves. Experiments have been performed with irregular waves to investigate wave forces, more particularly to study the influence of the energy density spectrum of the waves. Within the range of conditions m the experiments, the wave motion is sufficiently characterized by its energy and the frequency (or wave period) at which the energy density is maximum to determine the probability distribution of wave forces.

VIBROSEIS DOWN THE HOLE

1983 ◽  
Vol 23 (1) ◽  
pp. 203
Author(s):  
J. T. Frazer
Keyword(s):  
Seismic Data ◽  
Seismic Source ◽  
Seismic Signal ◽  
Structure Mapping ◽  
Time Duration ◽  
Seismic Section ◽  
Reflection Seismic ◽  
The Past ◽  
Field Estimation ◽  
Seismic Reflections

A variety of problems associated with the Vibroseis® source have been encountered over the past few years which have presented difficulties in tieing surveys using different control systems and in depth mapping.Accurate depth structure mapping and field estimation from seismic data requires good correlation of seismic reflections with stratigraphic boundaries. The information required, a known seismic signal and vertical rock velocities can only be obtained from measurements down the hole.Seismic time to depth correlation can be obtained from an integrated sonic velocity curve tied to conventional well shoot data only if the source is the same as that used for the reflection seismic data or the relation between the well shoot and seismic source is known. It has been apparent for some time that the signal from the Vibroseis source has not been adequately defined from surface measurements.A number of parameters must be monitored to ensure that the signal transmitted during a Vibroseis sweep is properly calibrated. The synchronisation of phase, time duration of the sweep, sweep bandwidth, vibrator drive levels and the phase relation of the pilot sweep to the signal transmitted from the baseplate, contribute to determine the character of the signal seen on a seismic section.®Trademark of Conoco, Inc.

Attenuation of Pn from offshore Maine explosions

1965 ◽  
Vol 55 (2) ◽  
pp. 417-423
Author(s):  
G. E. Frantti
Keyword(s):  
Energy Spectrum ◽  
Energy Density ◽  
Gulf Of Maine ◽  
Time Window ◽  
Seismic Energy ◽  
Seismic Source ◽  
P Wave ◽  
Frequency Interval ◽  
Underwater Explosions ◽  
Approximate Frequency

Abstract The attenuation of Pn based on seismic energy density in a three-second time window was examined as a function of frequency in the distance range 204.0 ≦ Δ ≦ 346.4 km for underwater explosions in the Gulf of Maine. The diffracted P wave contained energy in the approximate frequency interval 1.25 to 20 cps and attenuation over this portion of the spectrum exhibited an unusual frequency-dependence with little scatter in the data. Dissipation constants are estimated from these observations. Integration of the extrapolated energy spectrum suggests empirically that the seismic source efficiency is about 8 per cent.

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