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31.
Gyula Gábris 《地学学报》1994,6(5):495-501
The present-day drainage system of the Carpathian Basin originates from the gradual regression of the last marine transgression (brackish Pannonian Sea). The flow directions of the rivers including the Danube, are determined by the varying rates and locations of subsidence within the region. The Danube, which forms the main axis of the drainage network, first filled the depression of the Little Plain Lake and then, further southward, the Slavonian Lake. From the end of the Pliocene, the crustal movements which caused the uplift of the Transdanubian Mountains, forced the Danube to flow in an easterly direction, towards the antecedent Visegrid Gorge, and into the subsiding basins of the Great Plain. Climatic changes during the Pleistocene had the effect of forming up to seven fluvial terraces. The uplift of the mountains is demonstrated by the deformation of the terraces, while the subsidence of the Plains is proven by an accumulation of several hundred metres of sediment. The river only occupied its present position south of Budapest in the latest Pleistocene. 相似文献
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Zsolt Kővári Katalin Oláh János Bartus Klaus G. Strassmeier Michael Weber Albert Washuettl John B. Rice Szilárd Csizmadia 《Astrophysics and Space Science》2006,304(1-4):375-377
Doppler images are presented for the RS CVn-type binary ζ And. Our upgraded Doppler imaging code TempMapε takes into account the distorted geometry of the primary giant component. On the maps several low latitude spots are restored with a temperature contrast of about 1000 K. Some weak polar features are also found. Cross-correlation of the consecutive Doppler-maps suggests solar-like differential surface rotation. 相似文献
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Moonquakes and lunar tectonism 总被引：1，自引：0，他引：1
Gary Latham Maurice Ewing James Dorman David Lammlein Frank Press Naft Toksőz George Sutton Fred Duennebier Yosio Nakamura 《Earth, Moon, and Planets》1972,4(3-4):373-382
With the succesful installation of a geophysical station at Hadley Rille, on July 31, 1971, on the Apollo 15 mission, and the continued operation of stations 12 and 14 approximately 1100 km SW, the Apollo program for the first time achieved a network of seismic stations on the lunar surface. A network of at least three stations is essential for the location of natural events on the Moon. Thus, the establishment of this network was one of the most important milestones in the geophysical exploration of the Moon. The major discoveries that have resulted to date from the analysis of seismic data from this network can be summarized as follows:
- Lunar seismic signals differ greatly from typical terrestrial seismic signals. It now appears that this can be explained almost entirely by the presence of a thin dry, heterogeneous layer which blankets the Moon to a probable depth of few km with a maximum possible depth of about 20 km. Seismic waves are highly scattered in this zone. Seismic wave propagation within the lunar interior, below the scattering zone, is highly efficient. As a result, it is probable that meteoroid impact signals are being received from the entire lunar surface.
- The Moon possesses a crust and a mantle, at least in the region of the Apollo 12 and 14 stations. The thickness of the crust is between 55 and 70 km and may consist of two layers. The contrast in elastic properties of the rocks which comprise these major structural units is at least as great as that which exists between the crust and mantle of the earth. (See Toks?zet al., p. 490, for further discussion of seismic evidence of a lunar crust.)
- Natural lunar events detected by the Apollo seismic network are moonquakes and meteoroid impacts. The average rate of release of seismic energy from moonquakes is far below that of the Earth. Although present data do not permit a completely unambiguous interpretation, the best solution obtainable places the most active moonquake focus at a depth of 800 km; slightly deeper than any known earthquake. These moonquakes occur in monthly cycles; triggered by lunar tides. There are at least 10 zones within which the repeating moonquakes originate.
- In addition to the repeating moonquakes, moonquake ‘swarms’ have been discovered. During periods of swarm activity, events may occur as frequently as one event every two hours over intervals lasting several days. The source of these swarms is unknown at present. The occurrence of moonquake swarms also appears to be related to lunar tides; although, it is too soon to be certain of this point.