Oxidation kinetics of Cu(I) in seawater: implications for its existence in the marine environment     

James W Moffett  Rod G Zika 《Marine Chemistry》1983,13(3):239-251

A variety of photochemical and thermochemical processes may lead to the formation of Cu(I) in the upper water column. A thermodynamic model based on measured steady state levels of H₂O₂ in the photic zone indicates that a significant proportion of total dissolved Cu is present as Cu(I).The oxidation kinetics of Cu(I) in seawater have been studied to assess the potential for Cu(I) to accumulate at significant steady state levels when it is generated by non-equilibrium processes.  相似文献   

Rayleigh-Wave Dispersion Along the Hawaiian Swell: A Test of Lithospheric Thinning By Thermal Rejuvenation At A Hotspot   总被引：2，自引：0，他引：2  

Mark T. Woods  Emile A. Okal 《Geophysical Journal International》1996,125(2):325-339

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The alpine Swiss-French airborne gravity survey   总被引：3，自引：0，他引：3  

Jérôme Verdun  Emile E. Klingelé  Roger Bayer  Marc Cocard  Alain Geiger  Hans-Gert Kahle 《Geophysical Journal International》2003,152(1):8-19

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Single-station estimates of the seismic moment of the 1960 Chilean and 1964 Alaskan earthquakes,using the mantle magnitudeM m     

Emile A. Okal  Jacques Talandier 《Pure and Applied Geophysics》1991,136(1):103-126

Measurements are taken of the mantle magnitudeM _m , developed and introduced in previous papers, in the case of the 1960 Chilean and 1964 Alaskan earthquakes, by far the largest events ever recorded instrumentally. We show that theM _m algorithm recovers the seismic moment of these gigantic earthquakes with an accuracy (typically 0.2 to 0.3 units of magnitude, or a factor of 1.5 to 2 on the seismic moment) comparable to that achieved on modern, digital, datasets. In particular, this study proves that the mantle magnitudeM _m does not saturate for large events, as do standard magnitude scales, but rather keeps growing with seismic moment, even for the very largest earthquakes. We further prove that the algorithm can be applied in unfavorable experimental conditions, such as instruments with poor response at mantle periods, seismograms clipped due to limited recording dynamics, or even on microbarograph records of air coupled Rayleigh waves.In addition, we show that it is feasible to use acoustic-gravity air waves generated by those very largest earthquakes, to obtain an estimate of the seismic moment of the event along the general philosophy of the magnitude concept: a single-station measurement ignoring the details of the earthquake's focal mechanism and exact depth.  相似文献   

Intraplate seismicity of antarctica and tectonic implications     

Emile A. Okal 《Earth and Planetary Science Letters》1981,52(2):397-409

We present a comprehensive study of the seismicity of the Antarctic plate for the period 1925–1980. The total seismic energy released during this period in the interior of the plate, 3.2 × 10²² ergs, is compared to figures for the African plate, of similar kinematics and size, and to the neighboring Nazca plate. We conclude that Antarctic seismicity is comparable to that of other plates, thus refuting the claim that a surrounding ring of spreading ridges hampers transmission of tectonic stress and leaves it stress-free, and clearly showing the importance of ridge-push as a driving mechanism for the plates. In the souteastern Pacific Basin, it is shown that the line of maximum age in the plate, which is the locus of previous positions of the triple junction, is a line of preferential stress release, along with more conventional features, e.g. fracture zones. In the Indian Ocean, we study a 1973 earthquake northeast of Kerguelen (M_s = 5.5): its depth (45 km), tensional mechanism, and low stress suggest that it represents a magmatic process related to the nearby hotspot, and possibly involving the pipeline structure proposed by Morgan.  相似文献   

The Bellingshausen Sea earthquake of February 5, 1977: Evidence for ridge-generated compression in the Antarctic plate     

Emile A. Okal 《Earth and Planetary Science Letters》1980,46(2):306-310

Body- and surface-wave data from a magnitude M_s = 6.4 event in the Bellingshausen Sea are used to infer a thrust fault mechanism, with compressional stress directed parallel to the vector of relative motion between Antarctica and the Pacific plate at the nearby ridge. The solution would not, on the other hand, be compatible with stress fields involving absolute plate motion, such as asthenospheric drag.  相似文献   

A surface-wave investigation of the rupture mechanism of the Gobi-Altai (December 4, 1957) earthquake     

Emile A. Okal 《Physics of the Earth and Planetary Interiors》1976,12(4):319-328

Long-period records of multiple Love waves from the 1957 earthquake in Mongolia (M_S = 8.0) at Pasadena are analysed and compared to synthetic seismograms, generated by the method of Kanamori. A fit in the time domain shows that the records are not consistent with the previous solution, achieved through a frequency-domain analysis of directivity by Ben-Menahem and Toksöz. The solution asks for a shorter rupture of 270 km at a velocity of 3.5 km/s. The focal parameters are constrained by updating all the reported first motion and are found to be: strike = 103°, dip = 53°, slip = 32°. A seismic moment of 1.8 · 10²⁸ dyn · cm is obtained. These figures are also consistent with a time-domain analysis of Love waves at Palisades and Strasbourg, and of Rayleigh waves at Pasadena, with a directivity study of Love waves at Pasadena, and with static deformation and isoseismal data. A discussion is given of the relation between moment, magnitude and rupture area, and a comparison is made with other events in the same region: it is concluded that this earthquake does not exhibit an “intra-plate” behavior, but rather compares better with “inter-plate” events, such as the great Assam earthquake.  相似文献   

De la vitesse de sédimentation des microbes dans l'eau du Léman prélevée dans le Petit-lac     

Emile Novel 《Aquatic Sciences - Research Across Boundaries》1969,31(1):150-156

Résumé L'auteur a étudié, dans des conditions expérimentales définies, la vitesse de sédimentation des bactéries appartenant à l'espèceEscherichia coli dans l'eau du Léman, puisée dans le Petit-lac. Théoriquement la durée de chute est de 16 heures et 40 minutes pour un mètre. L'on voit ainsi que pour atteindre le fond du Léman en sa plus grande profondeur un colibacille mettrait 256 jours et 18 heures si rien ne venait entraver sa descente.

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Zusammenfassung Unter definierten Versuchsbedingungen wurde die Sedimentationsgeschwindigkeit von Bakterien der ArtEscherichia coli aus dem Genfersee (Lac Léman) studiert, und zwar mit Material aus dem Petit Lac. Theoretisch betr?gt die Sinkzeit pro Meter 16 h 40 min. Daraus geht hervor, dass ein Colibazillus, sofern er unbehindert absinken kann, 256 h 18 min ben?tigt, um den Grund des Genfersees an seiner tiefsten Stelle zu erreichen.

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Etudes bactériologiques des eux du Léman,prélevées dans le Petit-Lac pendant les années 1960, 1961 et 1962     

Emile Novel 《Aquatic Sciences - Research Across Boundaries》1965,27(2):238-249

Conclusions Si l'on examine les chiffres, aussi bien du point de vue qualitatif (recherche des coliformes) que du point de vue quantitatif (nombre total des germes) de la période 1957 à 1962¹), on remarque une aggravation sensible de la situation bactériologique ces dernières années et, notamment surtout, en 1961 et 1962.

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Summary The examination of the figures with regard to the qualitative point of view (coliforms) as well as to the quantitative one (total number of germs) for the period of 1957 to 1962¹) reveals an aggravation of the bacterial situation in the last years and, especially, in 1961 and 1962.

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Zusammenfassung Bei der Prüfung der Zahlen, sowohl in qualitativer (Colibakterien) als auch in quantitativer Hinsicht (Total der vorhandenen Keime) wird für die Zeit von 1957 bis 1962¹) eine merkliche Verschlechterung der bakteriologischen Verh?ltnisse festgestellt. Dies gilt besonders für die letzten Jahre, vor allem aber für 1961 und 1962.

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GIS goes nano: Vegetation studies in Victoria Land, Antarctica   总被引：1，自引：0，他引：1  

Lars Brabyn  Allan Green  Catherine Beard  Rod Seppelt 《New Zealand geographer》2005,61(2):139-147

Abstract: Vegetation in Antarctica consists mainly of algae, moss and lichen and is interesting to research because of the isolation and extreme growing conditions. An understanding of this vegetation is important for both the management of tourism in Antarctica, and because it provides a potential barometer of global climate and environmental change. This paper demonstrates two applications of GIS to mapping vegetation in Victoria Land, Antarctica. The first application computes the changes that have occurred to the vegetation within a 120 m by 28 m plot between 1962 and 2004. The second application maps and analyses the growth of a lichen specimen (Buellia frigida) during the same period. These applications demonstrate that GIS is a multiscale technology that can be used to detect detailed change in vegetation growth.  相似文献