A NOTE ON MULTIPLE REFLECTIONS

Geophysics ◽  
1949 ◽  
Vol 14 (3) ◽  
pp. 357-360
Author(s):  
G. E. Higgins
Keyword(s):  
Multiple Reflections ◽  
Geophysical Investigation ◽  
Seismic Prospecting ◽  
Reflection Seismic ◽  
Near Shore ◽  
Seismic Investigation

It was most interesting to read the January 1948 issue of Geophysics which was devoted to articles on multiple reflections and I would endorse the plea of Mr. Robert H. Mansfield for an issue of Geophysics to be devoted to the troublesome problems of offside energy in seismic prospecting. Trinidad has recently been the scene of intensive geophysical investigation, both gravimeter and reflection on seismic, and while neither method gives unambiguous answers to the local geologic problems, it is about the reflection seismic results which I should like to discuss. The first period of intensive seismic investigation in Trinidad was during 1938–1939 and certain anomalies observed then received further investigation during 1946–1947. During both periods of investigation, two particular phenomena were observed which may be called: 1. Near‐shore effect. 2. Coning.

scholarly journals 3D reflection seismic investigation for mine planning and exploration in the Kevitsa Ni‐Cu‐PGE deposit, northern Finland

2011 ◽  
Author(s):  
Alireza Malehmir ◽  
Christopher Juhlin ◽  
Chris Wijns ◽  
Milovan Urosevic ◽  
Petri Valasti ◽  
...  
Keyword(s):  
Mine Planning ◽  
Reflection Seismic ◽  
Seismic Investigation

3D reflection seismic investigation over a quick-clay landslide scar in Lilla Edet, south-western Sweden

2012 ◽  
Author(s):  
Emil Lundberg ◽  
Alireza Malehmir ◽  
Christopher Juhlin ◽  
Mehrdad Bastani
Keyword(s):  
Reflection Seismic ◽  
Quick Clay ◽  
Seismic Investigation

COMPOSITE REFLECTIONS

Geophysics ◽  
1950 ◽  
Vol 15 (1) ◽  
pp. 30-49 ◽  
Author(s):  
Norman Ricker ◽  
R. D. Lynn
Keyword(s):  
Free Surface ◽  
Shear Wave ◽  
Horizontal Component ◽  
Seismic Prospecting ◽  
Reflection Seismic ◽  
Quiet Region ◽  
Dilatational Wave ◽  
Cotton Valley ◽  
Ground Roll

This paper discusses the development of a method of reflection seismic prospecting based on the use of the seismic PS phase—a disturbance which has traveled from the shot to the reflecting bed as a dilatational wave and from the reflecting bed to the earth’s free surface as a shear wave, where it is picked up by horizontal component geophones. The reflection occurs on the seismogram in the otherwise quiet region between the dilatational waves and the ground roll and thus is never obscured by the ground roll. The reflection is quite clear and capable of spot correlation from spread to spread. The use of the method in delineating the Homer and Cotton Valley structures, near Minden, Louisiana, is described in detail. The method appears to be applicable to regions where an unconsolidated subsurface extends downwards from the earth’s surface to a single hard bed serving as a reflector. Criteria for identifying the disturbance as a composite reflection are given and the advantages and limitations of the method are discussed.

Reflection seismic investigation of the Dalasandstone area, Central Sweden

1989 ◽  
Vol 26 (1) ◽  
pp. 60
Author(s):  
Jonas Lindgren ◽  
Trine Dahl-Jensen
Keyword(s):  
Reflection Seismic ◽  
Seismic Investigation

scholarly journals Landslide tsunamis in lakes

2015 ◽  
Vol 772 ◽  
pp. 784-804 ◽  
Author(s):  
Louis-Alexandre Couston ◽  
Chiang C. Mei ◽  
Mohammad-Reza Alam
Keyword(s):  
Near Field ◽  
Finite Size ◽  
Wave Runup ◽  
Multiple Reflections ◽  
Time Period ◽  
Near Shore ◽  
Lakes And Reservoirs ◽  
Landslide Tsunami ◽  
Tsunami Energy ◽  
Landslide Tsunamis

Landslides plunging into lakes and reservoirs can result in extreme wave runup at the shores. This phenomenon has claimed lives and caused damage to near-shore properties. Landslide tsunamis in lakes are different from typical earthquake tsunamis in the open ocean in that (i) the affected areas are usually within the near field of the source, (ii) the highest runup occurs within the time period of the geophysical event, and (iii) the enclosed geometry of a lake does not let the tsunami energy escape. To address the problem of transient landslide tsunami runup and to predict the resulting inundation, we utilize a nonlinear model equation in the Lagrangian frame of reference. The motivation for using such a scheme lies in the fact that the runup on an inclined boundary is directly and readily computed in the Lagrangian framework without the need to resort to approximations. In this work, we investigate the inundation patterns due to landslide tsunamis in a lake. We show by numerical computations that Airy’s approximation of an irrotational theory using Lagrangian coordinates can legitimately predict runup of large amplitude. We also demonstrate that in a lake of finite size the highest runup may be magnified by constructive interference between edge waves that are trapped along the shore and multiple reflections of outgoing waves from opposite shores, and may occur somewhat after the first inundation.

DYNAMIC CORRELATION ANALYSIS

Geophysics ◽  
1968 ◽  
Vol 33 (1) ◽  
pp. 105-126 ◽  
Author(s):  
William A. Schneider ◽  
Milo M. Backus
Keyword(s):  
Space Time ◽  
Reliable Estimate ◽  
Analysis Tool ◽  
Multiple Reflections ◽  
Correlation Peak ◽  
Dynamic Correlation ◽  
Reflection Seismic ◽  
Relative Contribution ◽  
Analysis Technique ◽  
Energy Relationships

A computer analysis technique is described for use in conjunction with reflection seismic data shot for conventional common‐depth‐point (CDP) stacking, with the objective of providing a space‐time variant measure of the energy relationships among CDP traces. This energy analysis may be interpreted to yield an estimate of the relative contribution of primary and multiple reflections versus record time, their velocity functions, and the fraction of uncorrelated energy which is present. These data, in addition to their interpretive value, provide a space‐time variant model of the signal and noise fields for use in the design of optimum CDP stacking filters. The heart of the method is based upon crosscorrelations computed between CDP traces from numerous sequential short data gates along the trace. These are averaged over an ensemble of like members obtained along the line of profiles and manipulated to yield a reliable estimate of the cross correlation peak amplitude and delay upon which the primary and multiple velocity and energy assignments are based. The technique is illustrated with six‐fold marine data from the Gulf of Mexico to demonstrate how it can be used in practice as a valuable analysis tool for the exploration geophysicist.

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