0000000000335467
AUTHOR
Otto Rosenbach
THEORETISGHE UNTERSUCHUNGEN UBER DEN EINFLUSS DER VERWITTERUNGSSCHICHT AUF DAS SPEKTRUM ELASTISCHER WELLEN IN DER REFLEXIONSSEISMIK
The following assumptions are made in the mathematical treatment of the problem. Below a plane earth's surface there is a three-layered elastic medium the interfaces of which are parallel to the earth's surface. The uppermost layer represents the weathered layer in which the velocity of propagation of seismic waves increases linearly with depth. The two lower layers, the so-called intermediate layer and the substratum each have a constant velocity. The surface of the earth is acted on simultaneously by a normal pressure N in the form of a Heaviside pulse. The seismic wave thus generated is propagated through the elastic media. The aim of the investigation is to study the shape of the wave 1…
Bemerkungen über den Einfluss der Verwitterungsschicht auf das Spektrum seismischer Wellen
In Fortfuhung einer fruheren Arbeit der Autoren werden einige weitere theoretische Untersuchungen skizziert, bei denen die elastischen Eigenschaften der Verwitterungschicht geeignet abgeandert sind. Bei Anregung der Schicht durch einen momentanen Impuls (Nadelimpuls) ergibt sich, das die Frequenz der seismischen Welle nicht durch den Gradienten der Geschwindigkeit, sondern durch den Gradienten des Schallwiderstandes bestimmt wird.
PRINZIPIELLE BEMERKUNGEN ZU THEORIE UND PRAXIS DER METHODE DER ZWEITEN ABLEITUNG BEI DER INTERPRETATION GRAVIMETRISCHER MESSERGEBNISSE
The first part of the paper deals with theoretical considerations concerning the arithmetic mean of gravity values and its use with regard to the derivation of approximation formulae for the second derivative. In order to calculate the second derivative in practice the arithmetic mean. ḡ(r) of a continuum of gravity values on a circle of radius r is approximated by a Taylor polynomial and then replaced by the arithmetic mean gn(r) of n discrete gravity values. Because of the invariance of ġ(r) with regard to rotations of the coordinate system in the horizontal datum plane there exists a lower limit for the number n; this lower limit depends on the degree of the Taylor polynomial used in the…
THE QUANTITATIVE RECORDING OF SEISMIC EVENTS WITH EXTREMELY LARGE AMPLITUDE VARIATIONS BY DISCONTINUOUS GAIN CONTROL*
A transistorized combination of multivibrators is described, by which the gain is set according to a time programme. This equipment allows quantitative recording of seismic events with extremely large amplitude variations. Some possible applications of this recording system to seismic research are discussed. ZUSAMMENFASSUNG Es wird eine transistorisierte Zeitschalterkombination beschrieben, die zur Einstellung vorgewahlter Verstarkungsstufen nach Zeitprogramm dient. Mit dieser Anordnung lassen sich seismische Vorgange mit beliebigen Amplituden-Anderungen quantitativ erfassen. Es werden einige Beispiele der seismischen Forschung diskutiert, bei denen diese Regis-triertechnik erfolgreich eing…
COMPARATIVE CONSIDERATIONS ON THE ENERGY CONTENT OF SEISMIC WAVES IN CENTRAL AND LINEAR PATTERN SHOOTING*
In continuation of a publication by Pierau and Mueller (1960), theoretical and experimental comparisons are made about the energy content of seismic waves for central and linear shotpoint arrangements. The following results are obtained: Using shotpoint arrangements as chosen for the investigation, the energy content of deep reflections is greater in linear than in central pattern shooting, provided that the total quantity of charge is the same in both cases. Furthermore the seismograms obtained with linear shotpoint arrays are less disturbed by surface waves than those obtained in central pattern shooting. Both effects are superimposed and improve considerably the signal-to-noise ratio, th…