Transient waves in visco-elastic media: Norman H. Ricker. Elsevier Scientific Publishing Co., Amsterdam-Oxford-New York,N.Y., 1977, 278 pp., Dfl. 120.00/US $ 48.95     

Markus Båth 《Physics of the Earth and Planetary Interiors》1978,16(2):179-180

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Seismic wave velocities in the lower mantle — Part II     

Markus Båth 《Pure and Applied Geophysics》1967,68(1):19-23

Summary In an earlier paper the author developed mathematical expressions for the longitudinal and transverse wave velocities in the lower mantle in the form of power functions of the radius. In the present paper we shall instead develop the velocities as power series or polynomials of the radius. The two procedures are compared with regard to accuracy and convenience in applications. The power series expansion can permit higher accuracy in the representation of the velocities, but often entails greater complications in applications.  相似文献   

Propagation ofSn andPn to teleseismic distances     

Markus Båth 《Pure and Applied Geophysics》1966,64(1):19-30

Summary Sn andPn waves propagated to teleseismic distances are investigated by means of short-period seismograph records of the Swedish network.Sn is found in the distance range of 2400 to 4600 km andPn in the range 3500 to 3900 km, but only provided the path is exceptionally homogeneous. Almost all paths are restricted to the Russian platform. There are probably very few areas in the world offering similar propagation paths. The velocities just under the Mohorovii discontinuity are found to be 4.72 km/sec and 8.26 km/sec for transverse and longitudinal waves respectively. In addition, other properties of the teleseismicSn andPn are investigated, such as periods, dispersion, amplitudes, particle motions, propagation mechanisms, and comparisons are made withPa, Sa, withLi, Lg1, Lg2 and withP. The fact that teleseismicPn occurs much more seldom than teleseismicSn could be explained by different velocity profiles just under the crust.  相似文献   

Surface-wave magnitude corrections for intermediate and deep earthquakes     

Markus Båth 《Physics of the Earth and Planetary Interiors》1985,37(4):228-234

The small amplitudes of surface waves for intermediate and deep-focus earthquakes lead to too low values of the surface-wave magnitudes. On the basis of available material, average magnitude corrections are deduced, which increase with focal depth and amount to 0.1–0.5 for focal depths of 50 100 km and to 0.5–0.7 for depths of 100–700 km.  相似文献   

Analogy between elastic and electric systems     

Rune Olsson  Markus Båth 《Physics of the Earth and Planetary Interiors》1975,10(1):1-11

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Geochronological and Petrogenetic Studies of High-Grade Metamorphic Rocks and Intrusives in Namaqualand, South Africa     

CLIFFORD  T. N.; GRONOW  J.; REX  D. C.; BURGER  A. J. 《Journal of Petrology》1975,16(1):154-188

The metamorphic sequence in the Nababeep district of Namaqualandis considered in terms of major recumbent folding accompaniedby hornblende granulite subfacies metamorphism. Rb-Sr isotopicdata are presented for thirty-one whole-rock samples of metamorphicrocks and associated intrusives, together with U-Pb isotopicdata for nineteen fractions of the constituent zircon and apatite.The metamorphic suite has yielded a Rb-Sr whole-rock isochronage of 1213?22 m.y., with an initial Sr⁸⁷/Sr⁸⁸ ratio (R_o) of0?7191?0?0021 suggesting reworking of pre-existing crustal rocks;data from certain distinctive rock-types indicate that Sr-isotopichomogenization was incomplete during this event. Cross-cuttinggranites and related rocks give a Rb-Sr isochron age of 1166?26m.y. (R_o, 0?708?0?001). These events were post-dated by theintrusion of largely dioritic bodies of the cupriferous NoritoidSuite; zircon recrystallization 1070 m.y. ago is interpretedas the age of emplacement of these bodies. On Sr-isotopic andchemical grounds, a source-bed model is tentatively suggestedfor the Noritoid Suite, involving derivation from gneisses andgranulites of intermediate-basic composition within the metamorphicsuccession. Isotopic events at 1000 and 900 m.y. ago, recordedby zircon and apatite, are believed to reflect the imprint ofregional pegmatite emplacement.  相似文献   

A method for mapping seismic intensities applied to Sweden     

Markus Båth 《Tectonophysics》1980,66(4):T11-T18

Based on a combination of instrumental and macroseismic data, a method for calculating maximum seismic intensities is developed and applied to Sweden for the period 1951–1976. The method is particularly useful for areas with a low seismicity and a sparse population. Tectonophysical and engineering aspects on the resulting map are discussed.  相似文献   

Development of instrumental seismology in Sweden in 1949–1958     

Dr. Markus Båth 《Pure and Applied Geophysics》1959,43(1):108-130

Summary A review is given of the present (1959) seismological stations in Sweden, i.e. Uppsala, Kiruna, Skalstugan, and Göteborg, as well as of older stations, which are no longer in operation, i.e. Vassijaure, Abisko, and Lund, including all pertinent information. The disturbing effect of the loose ground at Lund in distinction from the four first-mentioned stations is clearly demonstrated. The very good ground at Uppsala, Kiruna, Skalstugan, and Göteborg, together with the use of modern equipment of high magnification has made these stations, especially Uppsala and Kiruna, very sensitive. This is obvious from the number of recorded earthquakes. The method of time measurements, including direct recording of time signals, is described, and means to reach a high time accuracy are outlined, including the recommendation to use quartz clocks. Long-period (0.5–2 min) disturbances on the long-period Benioff combinations were mainly due to air currents in the seismometer room and were eliminated by providing the seismometers with special covers. The method of ground amplitude determinations is outlined, especially for the Benioff instruments, and typical magnification curves are given. Comparisons of ground amplitudes from simultaneous records of BenioffE, N and WiechertE, N and of BenioffZ and GrenetZ have been made. The amplitude comparison between Benioff and Wiechert has given a new estimate of the effect of friction (especially of the recording pen against the paper) in the Wiechert apparatus.

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Zusammenfassung Eine Übersicht sowohl von den gegenwärtigen (1959) seismologischen Stationen in Schweden, d.h. Uppsala, Kiruna, Skalstugan und Göteborg, als auch von früheren Stationen, die nicht mehr im Betrieb sind, d.h. Vassijaure, Abisko und Lund, wird gegeben. Die störende Wirkung des lockeren Bodens in Lund zum Unterschied gegen die vier erstgenannten Stationen wird deutlich hervorgehoben. Der sehr gute Untergrund in Uppsala, Kiruna, Skalstugan und Göteborg und die Verwendung moderner Apparate hoher Vergrösserung haben diese Stationen, besonders Uppsala und Kiruna, sehr empfindlich gemacht. Dieser Umstand geht aus der Anzahl registrierter Beben hervor. Die Methode der Zeitmessungen (direkte Registrierung der Zeitsignale einbegriffen) wird beschrieben, und Massnahmen eine hohe Zeitgenauigkeit zu erreichen werden erwähnt, die auch die Verwendung von Quarz-Uhren umfassen. Langperiodische Störungen (Perioden 0.5–2 Min) auf den langperiodischen Benioff-Registrierungen waren hauptsächlich durch Luftströmungen im Seismometerraum verursacht und wurden durch spezielle Kappen über den Seismometern eliminiert. Die Methode der Bestimmung von Boden-Amplituden wird beschrieben, hauptsächlich für die Benioff-Instrumente, und typische Vergrösserungskurven sind gegeben. Vergleichungen der Bodenamplituden von parallelen Registrierungen von BenioffE, N und WiechertE, N und von BenioffZ und GrenetZ sind ausgeführt worden. Die Amplitudenvergleichung zwischen Benioff und Wiechert hat eine neue Schätzung des Einflusses der Reibung (speziell vom Schreibfeder gegen das Papier) im Wiechert-Seismographen gegeben.

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Continental dispersion of seismic surface waves     

Markus Bath  Andreas Vogel 《Pure and Applied Geophysics》1957,38(1):10-18

Summary Continental dispersion curves for Love and Rayleigh waves have been determined by means of the Uppsala seismograph records for three earthquakes near the south coast of Turkey in April, 1957. To the authors' knowledge this is the first time dispersion curves have been determined for a relatively homogenous path across the whole of continental Europe and covering a good range of periods, namely from 3 to 86 sec for Love waves and from 5 to 61 sec for Rayleigh waves. The dispersion curves obtained are relevant to determinations of the average structure along the path traversed in particular, and to determinations of crustal structure of the European continent in general.

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Zusammenfassung Kontinentale Dispersionskurven für Love-und Rayleigh-Wellen wurden vermittels Registrierungen an der Station Uppsala von drei Erdbeben in der Nähe der Südküste der Türkei im April 1957 bestimmt. Soweit es den Autoren bekannt ist, wurden damit erstmalig Dispersionskurven für einen relativ homogenen Weg über das gesamte kontinentale Europa mit einem beträchtlichen Periodenbereich, der 3 bis 86 Sek für Love-Wellen und 5 bis 61 Sek für Rayleigh-Wellen umfasst, ausgearbeitet. Die erhaltenen Dispersionskurven haben ihre Bedeutung in der Festlegung der mittleren Krustenstruktur entlang dem durchlaufenen Wellenweg und überhaupt in der Festlegung der Krustenstruktur im Bereich des europäischen Kontinents.

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Postglacial midge community change and Holocene palaeotemperaturereconstructions near treeline, southern British Columbia (Canada)     

Samantha Palmer  Ian Walker  Markus Heinrichs  Geoffrey Scudder 《Journal of Paleolimnology》2002,28(4):469-490

Stratigraphic analysis of fossil chironomid head capsules wasperformed at North Crater Lake and Lake of the Woods, located at treeline (2250m) in the Ashnola region of southernmost British Columbia. Priorto 10,000 yr BP, cold conditions were indicated by the lack oftemperate taxa and the presence of cold-stenotherms. The abundance anddiversity of warm-adapted taxa (e.g., Dicrotendipes,Microtendipes, Polypedilum and Cladopelma)increased rapidly after 9500 yr BP, whereas taxa indicative ofcold conditions disappeared. Beginning prior to deposition of the Mazama ash(6730 ± 40 yr BP), several warm-adapted taxa decreasedin abundance. Mid- to late-Holocene assemblages (ca. 4500yr BP to present) indicated continued cooling as revealed by afurther reduction in diversity and abundance of warm-adapted taxa atboth lakes, and the reappearance of cold-stenotherms in Lake of theWoods. Diversity changes in the cores paralleled the inferred climatic changes.Diversity was low during the late-glacial, increased in theearly-Holocene, and declined after 5400 yr BP.To quantitatively infer past climatic changes, a newweighted yphen;averaging partial-least-squares (WA-PLS)model was developed and applied to the fossil midge data. The quantitativereconstructions revealed late-glacial mean July air temperatures rangingfrom about 8 to 10°C. Summer air temperatures were highest inthe early Holocene (13 to 17°C), gradually decreasing by about3°C through the mid- to late-Holocene.  相似文献