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131.
Tectono-thermal modeling of the Yinggehai Basin,South China Sea 总被引:1,自引:0,他引:1
Lijuan?HeEmail author Liangping?Xiong Jiyang?Wang Jihai?Yang Weiliang?Dong 《中国科学D辑(英文版)》2001,44(1):7-13
Based on the observed data, the average value of surface heat flow in the Yinggehai Basin is calculated and it turns out to
be 84.1 mW/m2. The thermal evolution of the basin since the Cenozoic era has been attempted by tectono-thermal modeling. Three-phase extension
made the basin become hotter and hotter, reaching its climax in paleo-temperature history since 5.2 Ma. And nowadays, the
basin is in the heat flow decreasing period. During the Cenozoic era, the basement heat flow remained at 50–70 mW/m2 all the time. This is related to the degree of each extension phase, stretching rate mode and also the limited basin scale.
Modeling results also show that, the surface heat flow is controlled mainly by the basement heat flow, and less than 20% comes
from radiogenic heat production in the sediments of the basin 相似文献
132.
Coseismic and post-seismic signatures of the Sumatra 2004 December and 2005 March earthquakes in GRACE satellite gravity 总被引:2,自引:0,他引:2
Isabelle Panet Valentin Mikhailov Michel Diament Fred Pollitz Geoffrey King Olivier de Viron Matthias Holschneider Richard Biancale Jean-Michel Lemoine 《Geophysical Journal International》2007,171(1):177-190
The GRACE satellite mission has been measuring the Earth's gravity field and its temporal variations since 2002 April. Although these variations are mainly due to mass transfer within the geofluid envelops, they also result from mass displacements associated with phenomena including glacial isostatic adjustment and earthquakes. However, these last contributions are difficult to isolate because of the presence of noise and of geofluid signals, and because of GRACE's coarse spatial resolution (>400 km half-wavelength). In this paper, we show that a wavelet analysis on the sphere helps to retrieve earthquake signatures from GRACE geoid products. Using a wavelet analysis of GRACE geoids products, we show that the geoid variations caused by the 2004 December ( M w = 9.2) and 2005 March ( M w = 8.7) Sumatra earthquakes can be detected. At GRACE resolution, the 2004 December earthquake produced a strong coseismic decrease of the gravity field in the Andaman Sea, followed by relaxation in the area affected by both the Andaman 2004 and the Nias 2005 earthquakes. We find two characteristic timescales for the relaxation, with a fast variation occurring in the vicinity of the Central Andaman ridge. We discuss our coseismic observations in terms of density changes of crustal and upper-mantle rocks, and of the vertical displacements in the Andaman Sea. We interpret the post-seismic signal in terms of the viscoelastic response of the Earth's mantle. The transient component of the relaxation may indicate the presence of hot, viscous material beneath the active Central Andaman Basin. 相似文献
133.
Iodine contents of soils developed over the major rock formations of the northern zone of the Eastern Pontide Tectonic Belt
(Northeastern Turkey) have been investigated with respect to soil-parent rock relationship, effect of topography, elevation,
and climate to construe its effect on the health of the local population. Samples were collected from the A and B horizons
of the soils developed over the major stratigraphic units constituting the eastern Pontides, including the Lower Basic Complex
of Jurassic-Lower Cretaceous age, the Berdiga limestone (Jurassic-lower Cretaceous), the Dagbasi granitoid (Upper Cretaceous),
volcano-sedimentary sequence of Upper Cretaceous age, ore-bearing and barren dacites of Upper Cretaceous age, and Neogene
alkaline basalts. Chemical analyses of soil samples indicate significantly lower iodine abundances for all the soils studied
(5–28 ppm) in comparison to the average abundance of iodine in analogous soils of other parts of the world (22–93 ppm). The
concentration of iodine in soils developed over the same geologic formation decrease with increasing elevation. In certain
cases, this decrease may reach up to 70%. Goiter is highly common throughout this region in Turkey. The results of this study
suggest that the iodine deficiency of region’s soils may be a principal underlying cause for this area of Turkey being an
endemic goiter region. 相似文献
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1985年在甘肃文县屯寨乡洋汤寨的天池庙的大樑上发现了一条新的关于1879年7月1日武都8级地震的新的历史记载。该记载表明武都8级地震在这里的地震烈度至少达到了Ⅹ度。 相似文献
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140.
BP神经网络识别塔北低阻油气层 总被引:10,自引:1,他引:10
简要介绍了塔北低阻油气层岩性剖面、低阻油气层地球物理测井曲线特征,分析了塔北地区低阻油气储层成因,重点论述BP人工神经网络识别油气层、油水同层、水层和干层的方法原理。识别实例表明,BP人工神经网络识别低阻油(气)、水层的结果与实际相符,明显地提高了测井的解释精度。 相似文献