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961.
962.
963.
B. A. Hobbs 《Geophysical Journal International》1982,68(1):253-264
Summary. A method is described for finding a resistivity model that fits given magnetotelluric data in the one-dimensional case. The procedure is automatic and objective in that no a priori model structure is imposed. Starting with a uniform half space derived directly from the data, the procedure gradually transforms the half space to one with a continuous and smooth resistivity distribution whose response fits the measured data. The method is illustrated by application to two magnetotelluric data sets. 相似文献
964.
965.
966.
Giuliano F. Panza Fabio Romanelli & Tatiana B. Yanovskaya 《Geophysical Journal International》2000,141(2):498-508
We study how the tsunami mode is generated by a scaled double-couple seismic source, and how it propagates in realistic oceanic models. The method developed and used is the direct extension to tsunami waves propagating in multilayered oceanic media of the well-known Haskell method. The most intensive tsunamis may be expected from sources located within the crust in the deep-water parts of the ocean. The extension to laterally heterogeneous structures shows that, if the thickness of the ocean liquid layer diminishes, the maximum amplitude of the tsunami wave train increases. 相似文献
967.
G.H. Denton T.V. Lowell C.J. Heusser C. Schlüchter B.G. Andersen Linda E. Heusser P.I. Moreno & D.R. Marchant 《Geografiska Annaler: Series A, Physical Geography》1999,81(2):167-229
Glacial geomorphologic features composed of (or cut into) Llanquihue drift delineate former Andean piedmont glaciers in the region of the southern Chilean Lake District, Seno Reloncav', Golfo de Ancud, and northern Golfo Corcovado during the last glaciation. These landforms include extensive moraine belts, main and subsidiary outwash plains, kame terraces, and meltwater spillways. Numerous radiocarbon dates document Andean ice advances into the moraine belts during the last glacial maximum (LGM) at 29,363–29,385 14C yr BP , 26,797 14C yr BP , 22,295–22,570 14C yr BP , and 14,805–14,869 14C yr BP . Advances may also have culminated at close to 21,000 14C yr BP , shortly before 17,800 14C yr BP , and shortly before 15,730 14C yr BP . The maximum at 22,295–22,567 14C yr BP was probably the most extensive of the LGM in the northern part of the field area, whereas that at 14,805–14,869 14C yr BP was the most extensive in the southern part. Snowline depression during these maxima was about 1000 m. Andean piedmont glaciers did not advance into the outer Llanquihue moraine belts during the portion of middle Llanquihue time between 29,385 14C yr BP and more than 39,660 14C yr BP . In the southern part of the field area, the Golfo de Ancud lobe, as well as the Golfo Corcovado lobe, achieved a maximum at the outermost Llanquihue moraine prior to 49,892 14C yr BP . Pollen analysis of the Taiquemmire, which is located on this moraine, suggests that the old Llanquihue advance probably corresponds to the time of marine isotope stage 4. The implication is that the Andean snowline was then depressed as much as during the LGM. A Llanquihue-age glacier expansion into the outer moraine belts also occurred more than about 40,000 14C yr BP for the Lago Llanquihue piedmont glacier. 相似文献
968.
We explore the possibility of determining the actual fault plane of an earthquake from the inversion of near-source displacement seismograms of one station when a finite-dimension source is used instead of a point source model and when the complete displacement is taken into account, including near-field waves. Tests on synthetic seismograms and real data recorded at local distances show that this is possible even with a single, three-component station. A single accelerogram available for the Erzincan, Turkey, 1992 March 13, M s = 6.8 earthquake is inverted and the solution found is compatible with other seismological studies and with the mechanism expected for the North Anatolian Fault. 相似文献
969.
Carlsberg Ridge, northern Indian Ocean: gravity and isostasy 总被引:1,自引:0,他引:1
970.
Ikuho Yamada Barbara B. Brown Ken R. Smith Cathleen D. Zick Lori Kowaleski-Jones Jessie X. Fan 《The Professional geographer》2013,65(2):157-177
Obesity is a growing epidemic in the United States. Walkable neighborhoods, characterized as having the three Ds of walkability (population Density, land use Diversity, and pedestrian-friendly Design), have been identified as a potentially promising factor to prevent obesity for residents. Past studies examining the relationship between obesity and walkability vary in geographic scales of neighborhood definitions and methods of measuring the three Ds. To better understand potential influences of these sometimes arbitrary choices, we test how four types of alternative measures of land use diversity measured at three geographic scales relate to body mass index for 4,960 Salt Lake County adults. Generalized estimation equation models demonstrate that optimal diversity measures differed by gender and geographic scale and that integrating walkability measures at different scales improved the overall performance of models. 相似文献