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1.
Doron Nof 《地球物理与天体物理流体动力学》2013,107(1-3):71-87
Abstract The gamma plane approximation introduced in this study corresponds to a nonlinear horizontal shallow flow in a plane where, in addition to the familiar linear variation of f (i.e., β), there is a quadratic variation with latitude. Such a plane may have some application to the mesoscale oceanic flow in the immediate vicinity of the North Pole because at the pole the linear gradient (β) vanishes so that the quadratic variation (γ) is the dominant gradient. It is also applicable to the flow near the center of a rotating (laboratory) tank. Exact analytical solutions analogous to the stationary barotropic mid-latitude modons (Stern, 1975) are constructed. First, it is shown that, for a modon situated slightly off the pole (i.e., both β and γ are present) the condition of stationarity (in a resting ocean) takes the form β ∫∫ Ψ dxdy — 2γ ∫∫ yΨ dxdy = 0, where Ψ is the streamfunction and x and y are Cartesian coordinates pointing eastward and northward, respectively. Secondly, it is shown that due to the presence of γ, the cyclonic cell situated to the north increases in size and engulfs the southern anticyclone which decreases in size. Namely, as the pole is approached the engulfing cyclone grows whereas the anticyclone shrinks. Ultimately, when the center of the modon (whose diameter is R) reaches a critical distance from the pole (0.1227 R) the anticyclone diminishes to merely a point. Modons that are closer than this critical distance to the pole cannot contain an anticyclone. Far away from the pole our solution reduces to the familiar mid-latitude β-plane modon as should be the case. In contrast to these dramatic effects of γ on modons, the migration of monopoles (i.e., isolated cyclones or anticyclones) is almost unaffected by γ even though γ is of the same order of (or larger than) β. This results from the fact that the γ-induced perturbations are symmetrical (with respect to north and south) whereas those due to β are asymmetrical. It is shown that, as in other eddies, self-propulsion is primarily caused by asymmetrical perturbations so that disturbances due to γ have almost no influence on the migration. 相似文献
2.
Based on studies of the super large primary nugget discovered by Sun Zhenzuo (1983) in Linglong gold deposit, the emphasis in this paper is mainly put on geological features of the Su-perlarge-Linglong, nugget effect, independent nugget-visible gold metal… 相似文献
3.
ＯｂｓｅｒｖａｔｉｏｎａｎｄｒｅｓｅａｒｃｈｏｎＵＬＦａｎｄＶＬＦｓｅｉｓｍｏ－ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃｒａｄｉａｔｉｏｎＪＩＡ－ＺＨＩＹＵＡＮ（袁家治）；ＫｏｚｏＴａｋａｈａｓｈｉ；ＳＨＵ－ＱＩＮＧＱＩＡＮ（钱书清），ＹｏｋｉｏＦｕｊｉｎａｗ... 相似文献
4.
ＩＮＴＲＯＤＵＣＴＩＯＮＲｅｓｅａｒｃｈｏｎｅａｒｔｈｑｕａｋｅｆｏｃｕｓｄｅｐｔｈｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｉｔｓｐｈｙｓｉｃａｌｂａｃｋｇｒｏｕｎｄｉｓｏｎｅｏｆｍｏｓｔａｔ ｔｅｎｔｉｖｅｐｒｏｂｌｅｍｓ.Ｐｒｏｆ.ＦｕＺｈｅｎｇｘｉａｎｇ (1 996)ｒｅｓｅａｒｃｈｅｄｔｈｅｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｆｏｃｕｓｄｅｐｔｈｄｉｓｔｒｉｂｕ ｔｉｏｎｏｆａｆｔｅｒｓｈｏｃｋｓ ,ｃｒｕｓｔａｌｖｅｌｏｃｉｔｙｌａｙｅｒｓａｎｄｓｕｒｆａｃｅｔｈｅｒｍａｌｆｌｏｗ .Ｒｅｓｅａｒｃｈｏｎｆｏｃｕ… 相似文献
5.
Petrophysical evaluation and its application to AVO based on conventional and CMR-MDT logs 总被引：1，自引：0，他引：1
常规测井为 AVO 分析提供了基础的资料, 成为联系岩石物理与地震资料的桥梁。然而如果储层存在有复杂的流体系统, 如地层被严重地层流体侵入、电阻率响应低及盐水矿化度复杂等的现象, 则常规测井无法提供高质量的测井资料, 导致得出错误的弹性计算结果, 使 AVO 结果与地震资料不吻合。中国渤海湾地区第三系裂缝性储层复杂, 我们利用常规测井和核磁共振测井与模块地层动态测试相结合的组合仪完成了地层评价和储层描述。研究结果表明岩石物理学家利用上述方法技术可以获得诸如空隙度、渗透率、含水饱和度、束缚流体以及空隙压力等重要的储层参数并进一步综合应用这些结果和以实验室测量数据为基础的岩性分析结果进行在地震域岩石物理研究和 AVO 分析。 相似文献
6.
Wang Yanzhao 《中国地震研究》2007,21(4):355-364
Seismological and geodetic observations indicate that slow slip sometimes occurs in active fault zones beneath the seismogenic depth, and large slow slip can result in transient ground motion. Slow earthquakes, on the other hand, emit tremor-like signals within a narrow frequency band, and usually produce no catastrophic consequences. In general, slow slip and slow earthquakes probably correspond to deformation processes associated with releasing elastic energy in fault zones, and understanding their mechanisms may help improve our understanding of fault zone dynamic processes. This article reviews the research progress on slow slip and slow earthquakes over the last decade. Crustal motion and tremor activities associated with slow slip and slow earthquakes have been investigated extensively, mainly involving locating sources of slow slip and slow earthquakes and numerical modeling of their processes. In the meantime, debates have continued about slow slip and slow earthquakes, such as their origins, relationship, and mechanisms. 相似文献
7.
Introduction Bohai Bay, along with its adjacent areas, is one of the seismically active areas in North China. Understanding its crust/upper-mantle structural characteristics and lateral heterogeneity of the medium in this area is of great significance to the study of seismogenic environment, thus improvimg the level of earthquake prediction. For years, scientists have studied the area by gravity and magnetic methods (FENG, et al, 1989), geothermal field (WU, et al, 1988; TIAN, ZHANG, 19… 相似文献
8.
Bao Xueyang 《中国地震研究》2006,20(2):190-201
INTRODUCTIONThe modulus of rock is one of the basic elastic parameters of the earth’s medium. Under theassumption of linear elastic theory and Poisson medium,other parameters can be calculated fromit .But the real earth mediumis nonlinear elastic and has not a simple linear relationship between stressand strain.This causes relatively big differences betweenthe dynamic andthe static modulus of rock.In nonlinear elastic theory,the Young’s modulusEis replaced bythe nonlinear elastic modul… 相似文献
9.
WangChunyong 《中国地震研究》2002,16(3):283-292
The status of deep geophysical exploration and research in China is summarized in this paper.New achievements in the study of the velocity structure,seismotectonics and geodynamics of the crust and upper mantle are also briefly descibed. 相似文献
10.
Yan Yuding 《中国地震研究》2005,19(4):354-370
Experiment on rock hydraulic fracturing strength under different confining pressures was conducted on a series of test specimens with various pre-cracks prepared from 7 types of rock, Combining the data of an actual reservoir-induced earthquake with the experimental results of the contemporary tectonic stress field according to the theory of rock strength and the principle and method of rock fracture mechanics, the authors tentatively investigated the earthquakes induced by pore-water pressure in rock and obtained the initial results as follows： （1） One type of induced earthquake may occur in the case of larger tectonic stress on such weak planes that strike in similar orientation of principle tectonic compressional stress in the shallows of the rock mass; the pore-water pressure σp may generate tensile fracture on them and induce small earthquakes; （2） Two types of induced earthquake may occur in the case of larger tectonic stress, i, e,, ①on such weakness planes that strike in similar orientation of principle tectonic compressional stress, σ1, in the shallows of the rockmass, the pore-water pressure, σp, may generate tensile fracture on them and induce small earthquakes; ②When the tectonic stress approximates the shear strength of the fracture, the pore-water pressure σp may reduce the normal stress, σn, on the fracture face causing failure of the originally stable fracture, producing gliding fracture and thus inducing an earthquake. σp may also increase the fracture depth, leading to an induced earthquake with the magnitude larger than the previous potential magnitude; （3） There is a depth limit for each type of rock mass, and no induced earthquake will occur beyond this limit. 相似文献
11.
Introduction The characteristics of ground motions recorded near the fault of an earthquake are quite dif- ferent from the usual far-field ground motions. After the original recognition of their differences in the Port Hueneme earthquake in 1957, a great lot of inhabited structures and lifeline systems were damaged in the major earthquakes happened in the following years. The damages were beyond minds of seismologists and engineers. A quite rational reason is the lack of enough knowledge of t… 相似文献
12.
Study on NDVI-T_s space by combining LAI and evapotranspiration 总被引：1，自引：1，他引：1
Vegetation index and land surface temperature (Ts) are important parameters for land surface process modeling. The remotely sensed data in visible/near infrared and thermal infrared wavelengths have proven to be well suited to monitoring vegetation status, soil surface moisture conditions, drought and crop yield. More useful information can be created by integrated analyses of these two kinds of data, which will help us to study main principles of the temporal and spatial variations of land su… 相似文献
13.
Surveys in Geophysics - 相似文献
14.
Research on preservation and enrichment mechanisms of organic matter in muddy sediment and mudstone 总被引：4，自引：0，他引：4
CAI JinGong BAO YuJin YANG ShouYe WANG XingXin FAN DaiDu XU JinLi & WANG AiPing State Key Laboratory of Marine Geology Tongji University Shanghai China Institute of Earth Sciences Shengli Oil Company Dongying China 《中国科学D辑(英文版)》2007,50(5):765-775
Using multidiscipline methodologies, the differences in preservation and enrichment mechanisms of organic matter (OM) in muddy sediment and mudstone are investigated. In clay fractions, concentra- tions of TOC and chloroform bitumen “A” are significantly higher than those in coarser fractions. This indicates that clay minerals (CM) play an important role in enriching OM. The content of chloroform bitumen “A” increases obviously in the clay fraction, which reveals that dissolvable OM is the main composition of coalesce with clay minerals. Furthermore, TG and DTA data show that OM enrichment mechanisms and preservation forms have multiplicity. Several exothermic peaks in the DTA curves demonstrate that muddy sediment and mudstone contain a number of bioclasts and amorphous OM besides dissolvable OM. Through analyzing with XRD and DTA after mudstone samples were pretreated, the conclusions can be arrived at. Firstly, CM interlayer space of XRD curves and exothermic peaks of DTA curves both change as temperature increases. Secondly, the changes of CM interlayer space and exothermic peaks are concordant and stable around 350℃. All these are the features that OM enters CM interlayers to form stable organo-clay complexes. Therefore, the combination format of OM with CM is not only surface adsorption, partial OM enters CM interlayers to form stable organo-clay complexes. Finally, through the research on OM preservation forms and enrichment mechanisms in muddy sedi- ment and mudstone, the hydrocarbon-generation processes and the global carbon cycle and budget can be explained. 相似文献
15.
Zhang Xuemin 《中国地震研究》2004,18(3):242-252
Using pure S wave fitting method, we studied the shear wave velocity structures under the Ordos block and its eastern and southern marginal areas. The results show that the velocity structure beneath Yulin station in the interior of Ordos block is relatively stable, where no apparent change between high and low velocity layers exists and the shear wave velocity increases steadily with the depth. There is a 12km thick layer at the depth of 25km under this station, with an S wave velocity (Vs=3.90km/s) lower than that at the same depth in its eastern and southern areas (Vs≥4.00km/s). The crust under the eastern margin of Ordos block is thicker than that of the Yulin station, and the velocity structures alternate between the high and low velocity layers, with more low velocity layers. It has the same characteristic as having a 10km-thick low velocity layer (Vs=3.80km/s) in the lower crust but buried at a depth of aout 35km. Moreover, we studied the Vp/Vs ratio under each station in combination with the result of P wave velocity inversion. The results show that, the average velocity ratio of the Yulin station at the interior of Ordos block is only 1.68, with a very low ratio (about 1.60) in the upper crust and a stable ratio of about 1.73 in the mid and lower crust, which indicates the media under this station is homogenous and stable, being in a state of rigidity. But at the stations in the eastern and southern margins of the Ordos block, several layers of high velocity ratio (about 1.80) have been found, in which the average velocity ratio under Kelan and Lishi stations at the eastern margin is systemically higher than that of the general elastical body waves (1.732). This reflects that the crust under the marginal areas is more active relatively, and other materials may exist in these layers. Finally, we discussed the relationship among earthquakes, velocity structures beneath stations and faults. 相似文献
16.
《震灾防御技术》2022,17(4):775-783
为真实了解和深入研究居民地震保险购买意愿与行为的背离现象及其形成机制,以全国不同省份居民作为研究对象,开展专项问卷调查,并采用Logit模型进行回归分析,提出提升居民购买地震保险意愿并付诸行动的相关建议。研究结果表明,居民对地震断裂带的判断属于地震风险感知变量,对投保意愿和购买行为均产生显著的正向影响;是否购买其他保险和是否通过网络捐款属于普通风险感知变量,对投保意愿产生显著的正向影响,对购买行为产生正向影响但不显著;地震风险感知变量既可增强居民的投保意愿,又可促使居民付诸实际购买行动;普通风险感知变量虽能增强居民的投保意愿,但对购买行为无效力,使投保意愿和购买行为表现出一定程度的背离。 相似文献
17.
SUN Fu GAO Shan WANG Wei & QIAN Chengchun Physical Oceanography Laboratory Ocean University of China Qingdao China 《中国科学D辑(英文版)》2004,47(12):1147-1154
Since the 1940s, the significant progress has beenmade both in theory and in numeric study for oceanwaves. Beginning from the theory of generalized windwave spectra proposed by Wen[1], some distinctiveachievements have been obtained in China. A numberof original academic papers, for instance, were pub-lished in the late decades[2-10]. However, the study oflarge-scale effect of ocean waves has not been noticed,except for the introduction of information entropy ofocean wave height field to desc… 相似文献
18.
《地震学报(英文版)》1998,(4)
ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎＨ_２ｒｅｌｅａｓｅａｎｄｓｅｉｓ－ｍｉｃｉｔｙｏｎＸｉａｄｉａｎＦａｕｌｔＱＩＮＧ－ＷＵＧＡＯ（高清武）,ＮＩＬＩ（李霓）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｌｏｇｙ,ＣｈｉｎａＳｅｉｓｍｏｌｏｇｉｃａｌＢｕｒｅａｕ,... 相似文献
19.
This paper briefly reviewed the research progresses of earthquake prediction and/or forecasting in China during 1999～2002, especially focused on mid-short term prediction methods with approaches of seismicity, crustal de-formation, electromagnetism, ground water and the analysis by synthesis, and the application of the methods to the practice of earthquake prediction. 相似文献
20.
Zheng Rongzhang 《中国地震研究》2004,18(4):385-395
The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin fault of Altun, and in combination with the paleoclimatic data,the tectonic uplift since late Epipleistocene as revealed by stream terraces at the two places is discussed. At Yandantu, three levels of stream terraces( T1, T2 and T3 )have developed since 16ka BP, where T1, T3 and T2 are fill terraces and the buried major straths are exposed. The ages of three treads are dated to be about 16.1ka BP, 12 .Ska BP and 6.2ka BP, respectively. The three terraces reflect three tectonic uplift events, while the ages of the treads represent the occurrence time of these events. The stream is still beveling the bedrock and widening the channel at present, and the modern strath is being generated. The uplift rate is 4.8～4.5mm/a since 16.1 ka BP in this area. From 12.8ka B .P to 6.2ka BP, The uplift rate was 6.4mm/a.The uplift rate is 3. lmm/a since 6.2ka BP.At Changcaogou, four levels Of stream terraces(T1, T2, T3 and T1)have developed since 7ka BP. All of them are fill terraces. There are buried straths under the deposits. The buried major strath is exposed on T3 and T2 and the minor strath on T1‘and T1. The ages of treads of the three terraces (T3, T2 and T1’) are 7 ka BP, 3 ka BP and 2.5 ka BP, respectively. The four terraces reflect two uplift events induced by tectonic activities. One occurred in about 7 ka BP, and the other in 3ka BP. The uplift rate is 5.gmm/a since 7.0 ka BP at Changcaogou.From 7ka BP to 3ka BP, the uplift rate was 7.0mm/a, and since 3ka BP till now, the uplift rate is 4.7 mm/a. 相似文献