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901.
Between 1 January 1980 and 28 July 1981, a series of large earthquakes with body-wave magnitudes around 7, took place along the western segment of the Alpide belt. The sequence started in the Azores and migrated eastward along the belt at a rate of about 4400 km/yr with consecutive large events in northern Algeria, southern Italy, southern Greece and Iran. Two different methods are employed to identify similar series and corresponding migration velocities during earlier time periods of this century. The data set used contains all earthquakes with body-wave magnitudes larger than 6.3 and covers the time interval 1901–81. The concept of linear migration is tested for eastward and/or westward propagation, considering high migration velocities from 1600 to 11 000 km/yr. Results obtained are not homogeneous with respect to the two opposite migration directions, west-east and east-west, and we interpret this as a net drift of earthquake activity from the west to the east. Our efforts here are concentrated on analysis of observational data and on estabilishing the uniqueness of migration patterns. Because of the complexity of the tectonic system in question, we did not attempt to establish a mechanism explaining the migration of the observed earthquake sequences. 相似文献
902.
Dr. Klaus Rother 《GeoJournal》1986,13(1):27-35
In the Mediterranean area modern economic development is concentrating more and more on the favourably situated coastal plains. The coastal plains of Calabria, which are examined on the basis of land utilization mapping, form, in this backward S Italian region, individually characteristic areas of different levels of agrarian development. Areas with insufficient aid and stagnating development and those with a strong initial developmental impulse and hesitant further development, stand face-to-face with areas with a continuous upward trend. The latter fit into the ranks of those consolidated agricultural regions of S Italy in which government aid and private initiative are multifariously intertwined and together support the process of development. Up to now, however, the different non-agricultural interests have impeded the continuing progress of the process more and more and given rise to awkward land utilization conflicts. Through settlement expansion, the building of transport facilities and ports for industrial zones as well as tourism, the use of land for agriculture is, to an increasing extent, being taken away so that regional planning seems imperative. 相似文献
903.
904.
Summary Vertical temperature traces in the north-western Mediteranean show remarkably leafy structures at depths between 100 m and 300 m. The individual layers are stable over several days. Their horizontal extension is larger than 20 nm. The thickness amounts to 25–50 m. It is suggested that these interleavings of slightly different water masses are due to lateral mixing processes in the vicinity of the working area.
Inversionen unterhalb der Sprungschicht im nordwestlichen Mittelmeer
Zusammenfassung Temperaturprofile im nordwestlichen Mittelmeer weisen eine auffällig blättrige Struktur in Tiefen von 100–300 m auf. Die einzelnen Schichten sind über mehrere TAge stabil. Ihre horizontale Ausdehnung ist größer als 20 sm. Die vertikale Mächtigkeit beträgt 25–50 m. Es wird angenommen, daß die schichtförmigen Einschübe schwach unterschiedlicher Wassermassen durch Vermischung in der Umgebung des Arbeitsgebietes entstanden sind.
Inversions du gradient de température au-dessous de la thermocline dans le Nord Ouest de la Méditerranée
Résumé Les tracés verticaux de la température, dans le Nord Ouest de la Méditerranée ont des structures remarquablement superposées en minces feuillets, à des profondeurs comprises entre 100 et 300 mètres. Les couches individuelles sont stables pendant plusieurs jours. Elles s'étendent horizontalement sur plus de 20 milles nautiques. Leur épaisseur atteint 25 à 50 mètres. On suppose que ces superpositions de masses d'eau légèrement différentes sont dues à des processus de mélange latéral au voisinage de la région d'opération.相似文献
905.
906.
907.
908.
A total of 95 surface water samples (6 m depth) was collected during a transect from the Bothnian Bay to Kiel between 28 August and 5 September 1982. This report presents the dissolved trace metal (<0.4 μm) and the associated hydrographic and nutrient data. Except for aluminium, all other metals determined (Zn, Cd, Cu, Ni, Fe, Mn) showed a rather homogeneous distribution within the subregions, with highest values in the Bothnian Bay (except for Mn) and net variations of the individual samples of about 20%. Cadmium, copper and nickel reveal conservative behaviour when values from this study and literature data from the Kattegat and North Sea area are plotted against salinity. 相似文献
909.
910.