共查询到20条相似文献，搜索用时 469 毫秒
1.
AbstractThe Benzilan-Tangke deep seismic sounding profile in the western Sichuan region passes through the Song-pan-Garze orogenic belt with trend of NNE.Based on the travel times and the related amplitudes of phases in therecord sections,the 2-D P-wave crustal structure was ascertained in this paper. The velocity structure has quitestrong lateral variation along the profile.The crust is divided into 5 layers,where the first,second and third layerbelong to the upper crust,the forth and fifth layer belong to the lower crust.The low velocity anomaly zone gener-ally exists in the central part of the upper crust on the profile,and it integrates into the overlying low velocitybasement in the area to the north of Ma’erkang.The crustal structure in the section can be divided into 4 parts:inthe south of Garze-Litang fault,between Garze-Litang fault and Xiashuihe fault,between Xianshuihe fault andLongriba fault and in the north of Longriba fault,which are basically coincided with the regional tectonics division 相似文献
2.
黎凯武 《地震学报(英文版)》1998,(5)
ＩｎｔｒｏｄｕｃｔｉｏｎＵｎｔｉｌｎｏｗ,ｍａｎｙｏｂｓｅｒｖａｔｉｏｎｓａｎｄｓｔｕｄｉｅｓｓｈｏｗｔｈａｔｉｎａｃｅｒｔａｉｎａｒｅａｓａｎｄｄｕｒｉｎｇａｃｅｒｔａｉｎｐｅｒｉｏｄｍａｊｏｒｅａｒｔｈｑｕａｋｅｓｆｒｅｑｕｅｎｔｌｙｏｃｕｒｅｄ... 相似文献
3.
Sébastien Blaise Benjamin de Brye Anouk de Brauwere Eric Deleersnijder Eric J. M. Delhez Richard Comblen 《Ocean Dynamics》2010,60(3):535-554
At high Peclet number, the residence time exhibits a boundary layer adjacent to incoming open boundaries. In a Eulerian model,
not resolving this boundary layer can generate spurious oscillations that can propagate into the area of interest. However,
resolving this boundary layer would require an unacceptably high spatial resolution. Therefore, alternative methods are needed
in which no grid refinement is required to capture the key aspects of the physics of the residence time boundary layer. An
extended finite element method representation and a boundary layer parameterisation are presented and tested herein. It is
also explained how to preserve local consistency in reversed time simulations so as to avoid the generation of spurious residence
time extrema. Finally, the boundary layer parameterisation is applied to the computation of the residence time in the Scheldt
Estuary (Belgium/The Netherlands). This timescale is simulated by means of a depth-integrated, finite element, unstructured
mesh model, with a high space–time resolution. It is seen that the residence time temporal variations are mainly affected
by the semi-diurnal tides. However, the spring–neap variability also impacts the residence time, particularly in the sandbank
and shallow areas. Seasonal variability is also observed, which is induced by the fluctuations over the year of the upstream
flows. In general, the residence time is an increasing function of the distance to the mouth of the estuary. However, smaller-scale
fluctuations are also present: they are caused by local bathymetric features and their impact on the hydrodynamics. 相似文献
4.
CAO Yonggang LIU Changjian LIU Tongmu FENG Yanqing LIU Yuqiang LIAO Shizhi CHEN Yizhan 《中国地震研究》2019,33(1):97-111
The coupling numerical model between astronomical tide and tsunamis was built based on the data of the COMCOT model, which was verified by the Japan "3·11" tsunami. The tsunami source of the Manila seismic tsunami was designed and computed to analyze the risk of tsunami which will happen in the Guangdong coast. According to the results, the maximum quantity of water increasing and the time of the tsunami arriving at the Guangdong seacoast were calculated. The coupling simulation between astronomical tide and tsunamis has significant meaning for evaluating the risk and early-warning of tsunamis in the Guangdong coastal area. 相似文献
5.
ShuaiJun Wang FuYun Wang JianShi Zhang ShiXu Jia ChengKe Zhang JinRen Zhao BaoFeng Liu 《中国科学:地球科学(英文版)》2014,57(9):2053-2063
For the first time on the Chinese mainland, long-range wide-angle seismic reflection/refraction profiling technology has been applied to seismic wave phases from different depths and with different attributes within the various blocks of the North China Craton to characterize the structure of the crust and upper mantle lithosphere. By comparative analysis of the seismic wave phase characteristics in each block across a 1500-km-long east-west profile, we have identified conventional Pg, Pci, PmP and Pn phases in the crust, made a clear contrast between PL1 and PL2 waves belonging to two groups of lithospheric-scale phases, and produced a model of crust-mantle velocity structures and tectonic characteristics after one- and two-dimensional calculations and processing. The results show that the thickness of the crust and lithosphere gradually deepens from east to west along the profile. However, at the reflection/refraction interface, seismic waves in each group show obvious localized changes in each block. Also, the depth to the crystalline basement changes greatly, from as much as 7.8 km in the North China fault basin to only about 2 km beneath the Jiaodong Peninsula and Taihang-Lüliang area. The Moho morphology as a whole ranges from shallow in the east to deep in the west, with the deepest point in the Ordos Block at 47 km; in contrast, the North China Plain Block is uplifting. The L1 interface of the lithosphere is observed only to the west of Taihang Mountains, at a relatively slowly changing depth of about 80 km. The L2 interface varies from 75 to 160 km and shows a sharp deepening to the west of Taihang Mountains, forming a mutation belt. 相似文献
6.
Geochronological studies of mafic-ultramafic intrusions occurrence in the northern Dabie zone (NDZ) suggest that these pyroxenite-gabbro intrusions formed 120—130 Ma ago should be post-collisional magmatic rocks[1—4]. These mafic-ultramafic rocks provid… 相似文献
7.
Geology of the Grove Mountains in East Antarctica——New evidence for the final suture of Gondwana Land 总被引：4，自引：0，他引：4
As the core block of the East Gondwana Land, the East Antarctic Shield was traditionally thought, before 1992, as an amalgamation of a number of Archaean-Paleoproterozoic nuclei, be-ing welded by Grenville aged mobile belts during 1400—900 Ma, while the … 相似文献
8.
DONG Yunpeng ZHANG Guowei ZHAO Xia YAO Anping & LIU Xiaoming The Key Laboratory of Continental Dynamics Ministry of Education Department of Geology Northwest University Xi抋n China 《中国科学D辑(英文版)》2004,(4)
Being a composite collisional orogen between North China and South China blocks, the Qinling orogenic belt is the key to understand the composite combination, prolonged evolutionary history and their continental dynamics. The main suture between north and south Qinling, called Shangdan suture zone (SDSZ), had been studied in detail for about twenty years. Recently, another suture zone, called Mianl黣 suture zone (MLSZ), has been identified in the Qinling Mountains. It is characterized b… 相似文献
9.
Research on the 3—D Seismic Structures in Qinghai—Xizang Plateau 总被引：1，自引：0，他引：1
Based on the recording data from the analogue and broadband digital seismic stations in and around Qinghai-Xizang (Tibet)Platean,the three dimensiomal 3-D) seismic velocity stroctures in Qinghai-Xizang Plateau were obtained by using the regional body wave tomography and surface wave tomography.The results from these two tomography methods have similar characteristics for P-and S-wave velocity structures in crust and upper mantle.They show that there are remarkahle low velocity zones in the upper crust of L hasa block in the southern Qinghai-Xizang Plateau and the lower crust and upper mantle of Qiangtang block in the northern Qinghai-Xizang Plateau.These phenomena may be related to the different steps of collision process in southern and northern Qinghai-Xizang Plateau. 相似文献
10.
CHEN Xi HUANG Yue QIAN Jing LIU HaiLong FENG XianWei LIU Ying BAO AnMing WANG WeiSheng 《中国科学D辑(英文版)》2007,50(Z1):1-8
After analyzing the regulation of overflow ecological water consumption in the Canmrik ecological area of mainstream zone of the Tarim River, in this paper a model of ecological bifurcation is developed, the dynamic overflow process of ecological bifurcation is simulated, and the quantitative relationships between the volume of ecological water consumption and the ecological conservation extent and overflow time are analyzed using GIS, advance of freshet and RS means. The results reveal that the effects of discharge and time of ecological bifurcation on the efficiency of ecological water consump-tion are significant, there is a geometrical exponential relationship between the efficiency of ecological bifurcation and the water supply with different discharges and different times under the same eco-logical water consumption, hypsography plays an important role in ecological water consumption, the regulation of ecological water consumption cannot be equated with the ordinary farming irrigation system, a serious water waste will result and the prospective ecological benefits will not be able to be achieved if an ordinary ecological bifurcation is implemented. The efficiency of ecological water con-sumption can be increased by 30% by selecting the bifurcation schemes in an optimized way, which is of the utmost importance for arid areas with shortage of water resources. 相似文献
11.
Floods at the northern foothills of the Tatra Mountains — A Polish-Swiss research project 总被引：1，自引：1，他引：0
Zbigniew W. Kundzewicz Markus Stoffel Ryszard J. Kaczka Bartłomiej Wyżga Tadeusz Niedźwiedź Iwona Pińskwar Virginia Ruiz-Villanueva Ewa Łupikasza Barbara Czajka Juan Antonio Ballesteros-Canovas Łukasz Małarzewski Adam Choryński Karolina Janecka Paweł Mikuś 《Acta Geophysica》2014,62(3):620-641
The present paper introduces the topical area of the Polish-Swiss research project FLORIST (Flood risk on the northern foothills of the Tatra Mountains), informs on its objectives, and reports on initial results. The Tatra Mountains are the area of the highest precipitation in Poland and largely contribute to flood generation. The project is focused around four competence clusters: observation-based climatology, model-based climate change projections and impact assessment, dendrogeomorphology, and impact of large wood debris on fluvial processes. The knowledge generated in the FLORIST project is likely to have impact on understanding and interpretation of flood risk on the northern foothills of the Tatra Mountains, in the past, present, and future. It can help solving important practical problems related to flood risk reduction strategies and flood preparedness. 相似文献
12.
Xiang Hongf Wang Xuechao Hao Shujian Zhang Hui Guo Shunmin Li Jinzhao Li Hongwu Lin Yuanwu Zhang Wanxia 《中国地震研究》2001,15(2):124-133
On the basis of locating by the geochemical prospecting,shallow seismic sounding,drilling,geological profiling,and neogeochronological dating,we first found out the dislocation amount along the Liaocheng-Lankao buried fault since the Quaternary and the age of its latest activity phase and determined that the upper break point by the fault dislocation reaches 20m below the surface,The latest activity phase was in the early Holocene and the Fault is a shallow-buried active fault.An average dislocation rate along the fault is 0.12mm/a since the Quaternary.Thus,it is a buried active fault with intermediate to strong movement strength in the eastern china. 相似文献
13.
Crustal structure beneath the Songpan—Garze orogenic belt 总被引：2，自引：0，他引：2
The Benzilan-Tangke deepseismic sounding profile in the western Sichuan region passes through the Song-pan-Garze orogenic belt with trend of NNE.Based on the travel times and the related amplitudes of phases in the record sections,the 2-D P-wave crustal structure was ascertained in this paper.The velocity structure has quite strong lateral variation along the profile.The crust is divided into 5layers,where the first,second and third layer belong to the upper crust,the forth and fifth layer belong to the lower crust.The low velocity anomaly zone gener-ally exists in the central part of the upper crust on the profile,and it integrates into the overlying low velocity basement in the area to the north of Ma‘erkang.The crustal structure in the section can be divided into 4parts:in the south of Garze-litang fault,between Garze-Litang fault and Xianshuihe fault,between Xianshuihe fault and Longriba fault and in the north of Longriba fault,which are basically coincided with the regional tectonics division.The crustal thickness decreases from southwest to northeast along the profile,that is ,from62km in the region of the Jinshajiang River to 52km in the region of the Yellow River.The Moho discontinuity does not obviously change across the Xianshuihe fault basesd on the PmP phase analysis.The crustal average velocity along the profile is lower,about 6.30 km/s.The Benzilan-Tangke profile reveals that the crust in the study area is orogenic.The Xianshuihe fault belt is located in the central part of the profile,and the velocity is positive anomaly on the upper crust,and negative anomaly on the lower crust and upper mantle.It is considered as a deep tectonhic setting in favor of strong earthquake‘s accumulation and occurrence. 相似文献
14.
Artificial earthquake catalogue simulation is one of the ways to effectively improve the incompleteness of the existing earthquake catalogue,the scarcity of large earthquake records and the improvement of seismological research.Based on the Poisson distribution model of seismic activity and the Gutenberg-Richter magnitude-frequency relationship, the Monte Carlo method which can describe the characteristics of the stochastic nature and the physical experiment process is used.This paper simulates the future seismic catalogues of the Fenhe-Weihe seismic belt of different durations and conducts statistical tests on them. The analysis shows that the simulation catalogue meets the set seismic activity parameters and meets the Poisson distribution hypothesis,which can obtain a better simulated earthquake catalogues that meets the seismic activity characteristics.According to the simulated earthquake catalogues,future earthquake trends in this region are analyzed to provide reference for seismic hazard analysis. 相似文献
15.
INTRODUCTIONSeismicintensity measurestheintensityof anearthquake exerts onthe groundina certainarea .Itrepresents the averaged measurement of intensity of ground shakingin a certain scope and reflects theperception of peopleinearthquakes as well asthe areal andzonal distributions of earthquakeimpact onground buildings . The“Chinese Earthquake Intensity Scale”(Institute of Engineering Mechanics ,Chinese Academy of Sciences , 1980) describes one by one the correlative relations of huma… 相似文献
16.
The intensity of an earthquake is an important criterion and index for earthquake resistance, and disaster relief and for antiseismic engineering in large and medium sized cities. The earthquake data in Xinjiang are abundant and have been widely applied to the statistic relationship of seismic intensity of western China. However, there exists some unreasonable and man_made factors in them. We put forward the idea of area A_ 0-1 to express the effect of seismic intensity, studied the questions and influencing factors arising from uncertainty of intensity zoning and finally, proposed some solutions. 相似文献
17.
Some Thoughts on the Earthquake Science Experimental Site——The Underground Cloud Map 总被引：1，自引：0，他引：1
The Western Yunnan Earthquake Predication Test Site set up jointly by the China Earthquake Administration, the National Science Foundation Commission of America, and United States Geological Survey has played an important role in development of early earthquake research work in China. Due to various objective reasons, most of the predicted targets in the earthquake prediction test site have not been achieved, and the development has been hindered. In recent years, the experiment site has been reconsidered, and renamed the “Earthquake Science Experimental Site”. Combined with the current development of seismology and the practical needs of disaster prevention and mitigation, we propose adding the “Underground Cloud Map” as the new direction of the experimental site. Using highly repeatable, environmentally friendly and safe airgun sources, we could send constant seismic signals, which realizes continuous monitoring of subsurface velocity changes. Utilizing the high-resolution 3-D crustal structure from ambient noise tomography, we could obtain 4-D (3-D space + 1-D time) images of subsurface structures, which we termed the “Underground Cloud Map”. The “Underground Cloud Map” can reflect underground velocity and stress changes, providing new means for the earthquake monitoring forecast nationwide, which promotes the conversion of experience-based earthquake prediction to physics-based prediction. 相似文献
18.
19.
Most ecological and environmental issues faced by human society can only be solved at the ecosystem, watershed,regional and even global scale. Thus, ecological research is developing rapidly towards macro-scale studies. With the rapid development of observational networks and information technology, the spaceborne-aircraft-ground based observation system is becoming an important feature of ecosystem monitoring in the new era. With the gradual formation of the global new-generation observational systems and the rapid expansion of massive multi-source heterogeneous data, ecology has entered the era of big data, big science, and big theory. How to integrate ecological big data, discover valuable ecological laws and mechanisms, and further expand them to solve eco-environmental issues that closely relate to human development are the major opportunities and challenges in this field. In this paper, we systematically summarized the research progresses in ecological big data, reviewed the opportunity and demand of integrative ecology, and further discussed the main approaches of ecological big data integration by using meta-analysis, data mining, and data-model fusion. Finally, we proposed the prospects and research directions of integrative ecology and suggested that future researches need to integrate big data into land models so as to improve the accuracy of ecological forecasting. It can be foreseen that under the background of global change and the rapid development of big data in the future, integrative ecology will be extensively applied and developed to serve the sustainable development of human society. 相似文献
20.
Jarle Berntsen Lie-Yauw Oey Tal Ezer Richard Greatbatch Huijie Xue Yasumasa Miyazawa 《Ocean Dynamics》2014,64(10):1531-1534