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131.
2-D crustal Poisson’s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region 总被引:1,自引:0,他引:1
Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave
along the profile L
1 are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson’s
ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method,
and it is also very effective to determine Poisson’s ratio distribution of deep seismic sounding profile, especially useful
for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson’s ratio
body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson’s ratio
is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature.
There is a high Poisson’s ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot
substance. The lower part with high Poisson’s ratio, which stretches downward to Moho, is possibly the extrusion way of hot
substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination
of 3D crustal structure and magnetotelluric survey in this region.
Foundation item: Key Project from China Earthquake Administration and the Project (95-11-02-01) from Ministry of Science and Technology (2001DIA10003).
Contribution No. RCEG200401, Geophysical Exploration Center, China Earthquake Administration. 相似文献
132.
The central difference method (CDM) that is explicit for pseudo‐dynamic testing is also believed to be explicit for real‐time substructure testing (RST). However, to obtain the correct velocity dependent restoring force of the physical substructure being tested, the target velocity is required to be calculated as well as the displacement. The standard CDM provides only explicit target displacement but not explicit target velocity. This paper investigates the required modification of the standard central difference method when applied to RST and analyzes the stability and accuracy of the modified CDM for RST. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
133.
Naohiro Nakamura 《地震工程与结构动力学》2005,34(11):1391-1406
It is important to estimate the influence of layered soil in soil–structure interaction analyses. Although a great number of investigations have been carried out on this subject, there are very few practical methods that do not require complex calculations. In this paper, a simple and practical method for estimating the horizontal dynamic stiffness of a rigid foundation on the surface of multi‐layered soil is proposed. In this method, waves propagating in the soil are traced using the conception of the cone model, and the impulse response function can be calculated directly and easily in the time domain with a good degree of accuracy. The characteristics of the impedance, that is the transformed value to the frequency domain of the obtained impulse response, are studied using two‐ to four‐layered soil models. The cause of the fluctuation of impedance is expressed clearly from its relation to reflected waves from the lower layer boundary in the model. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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D. Shankar S. S. C. Shenoi R. K. Nayak P. N. Vinayachandran G. Nampoothiri A. M. Almeida G. S. Michael M. R. Ramesh Kumar D. Sundar O. P. Sreejith 《Journal of Earth System Science》2005,114(5):459-474
Hydrographic observations in the eastern Arabian Sea (EAS) during summer monsoon 2002 (during the first phase of the Arabian
Sea Monsoon Experiment (ARMEX)) include two approximately fortnight-long CTD time series. A barrier layer was observed occasionally
during the two time series. These ephemeral barrier layers were caused byin situ rainfall, and by advection of low-salinity (high-salinity) waters at the surface (below the surface mixed layer). These barrier
layers were advected away from the source region by the West India Coastal Current and had no discernible effect on the sea
surface temperature. The three high-salinity water masses, the Arabian Sea High Salinity Water (ASHSW), Persian Gulf Water
(PGW), and Red Sea Water (RSW), and the Arabian Sea Salinity Minimum also exhibited intermittency: they appeared and disappeared
during the time series. The concentration of the ASHSW, PGW, and RSW decreased equatorward, and that of the RSW also decreased
offshore. The observations suggest that the RSW is advected equatorward along the continental slope off the Indian west coast. 相似文献
138.
139.
为适应鄂尔多斯塔巴庙区块勘探开发需要,利用区域测井资料进行钻头选型,并结合现场实践优化钻头类型和钻井参数,提高钻井效率。通过新型PDC钻头推广应用,单口井所需钻头数量减少3~4只,减少起下钻3回次以上,缩短钻井周期3~5天。 相似文献
140.
随着县级城镇社会经济的迅速发展,城镇居民的休闲时间日渐增多,休闲时间的利用成为人们关注的焦点。以蒙自为案例地的中国经济欠发达地区县级城镇居民的休闲时间利用结构已经日趋多样化,但主要还是集中于看电视、散步、书报业务学习、家庭娱乐、做家务等几项传统休闲方式,家庭内休闲在城镇居民的休闲活动中占了很大比重,这反映出休闲时间利用低水平的问题。县级城镇休闲设施和休闲产业都比较落后,影响了城镇居民休闲质量的提高和休闲消费、休闲经济的发展。因此,政府及有关部门应努力改善城镇的休闲设施,大力发展休闲产业,从多方面引导居民科学、有效、合理地利用休闲时间,最终促进休闲经济的发展,提高城镇居民的生活质量。 相似文献