Some Experiments Concerning the Primary Seismic Pulse*

O'Brien, P. N. S.

doi:10.1111/j.1365-2478.1969.tb01992.x

Cited by 17 publications

(14 citation statements)

References 18 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It implies that both the amplitude and period of far field source wavelets will scale as the cube root of the mass or the energy of the charge. O'Brien (1969) found that this law held for both primary compressional (P) and shear (S) waves for charge weights varying from 0.08 to 9.5 kg. However, O'Brien also found that the larger charges were " more efficient generators of seismic energy "-that is, a larger fraction of the initial available energy is converted into elastic radiation by larger charges.…”

Section: Of the Scaling Law For A Buried Point Sourcementioning

confidence: 92%

Wavelet Deconvolution Using a Source Scaling Law*

Ziolkowski

Lerwill

March

et al. 1980

Geophysical Prospecting

View full text Add to dashboard Cite

We present a new method for the extraction and removal of the source wavelet from the reflection seismogram. In contrast to all other methods currently in use, this one does not demand that there be any mathematically convenient relationship between the phase spectrum of the source wavelet and the phase spectrum ofthe earth impulse response. Instead, it requires a fundamental change in the field technique such that two different seismograms are now generated from each source-receiver pair: the source and receiver locations stay the same, but the source used to generate one seismogram is a scaled version of the source used to generate the other. A scaling law provides the relationship between the two source signatures and permits the earth impulse response to be extracted from the seismograms without any of the usual assumptions about phase.. We derive the scaling law for point sources in an homogeneous isotropic medium. Next, we describe a method for the solution of the set of three simultaneous equations and test it rigorously using a variety of synthetic data and two types of synthetic source waveform: damped sine waves and non-minimum-phase air gun waveforms. Finally we demonstrate that this method is stable in the presence of noise.

show abstract

Section: Of the Scaling Law For A Buried Point Sourcementioning

confidence: 92%

Wavelet Deconvolution Using a Source Scaling Law*

Ziolkowski

Lerwill

March

et al. 1980

Geophysical Prospecting

View full text Add to dashboard Cite

show abstract

“…Since rocks are weaker in tension than in compression, the rock fails in tension and radial tension cracks are created in the permanently deformed nonlinear zone (e.g. O'Brien, 1969). Figure 1 shows the cavity, the nonlinear zone and the elastic zone.…”

Section: Theorymentioning

confidence: 99%

“…In the spectral ratio of the seismograms, the spectrum of the earth impulse response cancels, to give the ratio of the source spectra. A well‐known scaling relationship of the source time function and the cube root of the explosive energy (Werth and Herbst, 1963; O’Brien, 1969) allows the two source time functions to be found. This scaling does not take account of realistic differences in physical properties of the rock at the two source locations, however, and is not sufficient to explain all the observed differences in the seismograms.…”

Section: Introductionmentioning

confidence: 99%

“…It is known from close‐in or ‘free‐field’ measurements of dynamite (e.g. O’Brien, 1969) and underground nuclear explosions (Werth and Herbst, 1963; Rodean, 1971) that the nonlinear zone surrounding the source is small compared with a wavelength and behaves as a monopole source. This has guided the study of explosion source modelling (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Inversion of explosive source land seismic data to determine source signature parameters

Ziolkowski

2021

Geophysical Prospecting

View full text Add to dashboard Cite

In seismic land exploration, where terrain conditions limit the use of vibrator sources, explosive sources are the preferred choice, and in situations where low‐frequency energy is essential, explosive is the preferred source, because it contains energy down to DC (0 Hz). I present a new method to estimate the source time functions of explosion source seismic data, using a modified acquisition method, data processing, modelling and inversion. Two shots of different sizes are fired into the same geophone spread with source–receiver geometry arranged such that the Green's functions are essentially the same. The spectral ratio of corresponding seismic traces is then the spectral ratio of the source time functions. A corresponding synthetic ratio filter is calculated from Blake's explosion source model for the sources within each pair. Each modelled source is defined by five parameters: the minimum radius a of the elastic zone, the internal pressure p0 at a, the density of the rock ρ and two elastic constants for an isotropic rock, the P‐wave velocity c and Poisson's ratio σ. A grid search finds the source parameters that minimise the difference between the measured and synthetic filters for each source pair, thus yielding the two source time functions, but not their absolute amplitudes. Deconvolution of the shot records within each pair for the minimum‐phase source time functions recovers the estimated earth impulse response gathers, convolved only with the response of the recording system. The improved knowledge of the source signature is then helpful in subsequent processing, especially for reverse time migration, full waveform inversion and amplitude‐versus‐offset analysis. I consider shots at different depths in the same shot hole and shots at the same depth in different shot holes. The former configuration minimises differences in geophone coupling, and, in operations, quality control procedures must be met. There is considerable variation in recovered source parameters from place to place, caused by variations in charge size, soil or rock properties and source coupling.

show abstract

“…In a homogeneous rock stratum, the wavelet is influenced by the structure and physiomechanical characteristics of the rock; it is also affected by the excitation factors of the seismic source, such as the nature and charge weight of the explosives, the depth of the excitation well, and charging constitution [8][9][10][11][12]. To date, theoretical calculation methods for the relation between explosion parameters and the seismic source wavelet are limited in number [13,14], and studies in this respect have long been heavily relying on field experiments [8,12,[15][16][17]. However, field experiments cost high.…”

Section: Introductionmentioning

confidence: 99%

Influence of Seismic Source Parameters on the Excitation Wavelet in Seismic Explorations Based on Numerical Simulation

Qiu

Zeng

et al. 2020

Advances in Civil Engineering

View full text Add to dashboard Cite

Explosives are the most common seismic source in seismic explorations, whose excitation effect is closely associated with their properties, weight, buried depth, and charging constitution. This study analyzes the influence of seismic source parameters on the features of the explosion wavelet. The explosion process of the seismic source in marine carbonate is numerically simulated with the finite element software LS-DYNA. We consider three parameters, including buried depth, charge weight, and decoupling coefficient. To verify the simulation outcomes, we also carry out field observations. The appropriate buried depth of the explosive should be determined according to stratum lithology. As the charge weight increases, low-frequency energy of the source wavelet increases rapidly. The optimum charge weight is 16–18 kg, and the ideal charging structure is in a concentrated, short-column shape. Compared with the buried depth and charge weight, the decoupling coefficient shows more noticeable influence on the excitation effect of the source wavelet, and the optimum coefficient lies between 2.5 and 3. The results of this study may provide reference data for designing explosion parameters in field seismic explorations.

show abstract

Some Experiments Concerning the Primary Seismic Pulse*

Cited by 17 publications

References 18 publications

Wavelet Deconvolution Using a Source Scaling Law*

Wavelet Deconvolution Using a Source Scaling Law*

Inversion of explosive source land seismic data to determine source signature parameters

Influence of Seismic Source Parameters on the Excitation Wavelet in Seismic Explorations Based on Numerical Simulation

Contact Info

Product

Resources

About