Geostatistical inversion of coupled problems: dealing with computational burden and different types of data     

《Journal of Hydrology》2003,281(4):251-264

Practical application of geostatistical inversion to coupled problems is hampered by a number of difficulties. In this paper, we address two of them: first, the computational cost of sensitivity (Jacobian) matrices and, second, the evaluation of the relative weights of different types of data. Regarding the first, we revise the adjoint state equations to propose a form whose cost is independent of the number of unknown parameters and only grows with the number of observation wells. Regarding the second, we derive expressions for the relative weights of different types of data. These expressions are based on minimizing the expected likelihood, rather than the likelihood itself. The efficiency of both improvements is tested on a synthetic example. The example analyzes a wide range of groundwater flow and solute transport conditions. Yet, the expected likelihood consistently yields the optimal weights. The proposed form of the adjoint state equations leads to one order of magnitude reduction in CPU time with respect to the conventional sensitivity equations.  相似文献   

吐哈盆地中央构造带正反转演化特征   总被引：5，自引：3，他引：5  

朱文斌  马瑞士  郭令智  孙岩  徐鸣洁  胡德昭  王锋 《大地构造与成矿学》2003,27(2):125-131

吐哈盆地中央构造带由火焰山构造和七克台构造组成。中央构造带形成于三叠纪晚期至侏罗纪早期,表现为伸展构造特征,生长断层上盘地层厚度明显大于下盘,并于断层上盘所在的台北凹陷形成沉降中心。晚侏罗世,由于拉萨陆块与欧亚大陆的碰撞作用导致吐哈盆地由伸展盆地转变为挤压盆地,中央构造带也于此时发生构造反转,由早期的伸展正断层转变为挤压逆断层。发生于55Ma的喜山构造事件对天山地区产生了深刻的影响,但影响时间略有滞后,大致发生在晚渐新世至早中新世,中央构造带即在此次构造事件中强烈变形,逆冲出露于地表。  相似文献   

利用GPS位移和主应力方向观测资料进行川滇地区边界力的联合反演研究     

独知行  刘经南 《武汉大学学报(信息科学版)》2003,28(2):162-166,176

在简要介绍了川滇地区的构造格局和构造运动特征的基础上，讨论了不同观测数据同时用于反演的合理性和物理意义，利用1998～2000年观测的9个测点位移数据和1986年以前所测的10个主应力方向数据，将边界力和相对权比λ作为待反演参数，并考虑了主要活动断裂运动特性，进行了弹性有限元数值反演计算。计算结果表明，现今川滇地区的构造活动主要力源仍来源于印度板块与欧亚大陆的碰撞，菲律宾海板块的挤压作用也不可忽略，这一结论说明了该地区现今构造运动的继承性活动特征。  相似文献   

基于小波变换的GPS周跳探测   总被引：5，自引：0，他引：5  

岳建平  席广永 《测绘工程》2003,12(4):33-35

概述了GPS周跳产生的原因及其探测周跳的重要性，总结了用来进行检测的常用方法，重点讨论了用小波分析来检查周跳的基本思想。并用实际的工程算例验证了该方法的可行性和有效性。  相似文献   

POSITIVE INVERSION STRUCTURE OF THE CENTRAL STRUCTURE BELT IN TURPAN-HAMI BASIN   总被引：2，自引：0，他引：2  

ZHUWenbin MARuishi GUOLingzhi SUNYan XUMingjie HUDezhao 《大地构造与成矿学(英文版)》2003,27(1):179-190

The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall, and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.  相似文献   

Surface effects of triggered fault slip on Reykjanes Peninsula, SW Iceland     

Amy E. Clifton  Carolina Pagli  Jna Finndís Jnsdttir  Kristjana Eythorsdttir  Kristin Vogfjr 《Tectonophysics》2003,369(3-4):145-154

Three large earthquakes (M_w>4.5) were triggered within 5 min, 85 km west of a M_w 6.5 earthquake in the South Iceland Seismic Zone (SISZ). We report on surface effects of these triggered earthquakes, which include fresh rupture, widespread rockfall, disrupted rockslides and block slides. Field data confirm that the earthquakes occurred along N-striking right-lateral strike-slip faults. Field data also support the conclusion from modeling of InSAR data that deformation from the second triggered event was more significant than for the other two. A major hydrological effect was the draining of water through an open fissure on a lake bed, lowering the lake level by greater than 4 m. Field relationships suggest that a component of aseismic slip could have been facilitated by water draining into the fault zone.  相似文献   

Geomechanical model for the post-Variscan evolution of the Permocarboniferous–Mesozoic basins in Northeast Germany     

Christian A. Hecht  Christof Lempp  Magdalena Scheck 《Tectonophysics》2003,373(1-4):125

The Permocarboniferous basins in Northeast Germany formed on the heterogeneous and eroded parts of the Variscan orogene and its deformed northern foreland. Transtensional tectonic movements and thermal re-equilibration lead to medium-scale crustal fragmentation, fast subsidence rates and regional emplacement of large amounts of mostly acidic volcanics. The later basin formation and differentiation was triggered by reversals of the large-scale stress field and reactivation of prominent zones of weakness like the Elbe Fault System and the Rhenohercynian/Saxothuringian boundary that separate different Variscan basement domains in the area. The geomechanical behaviour of the latter plays an important role for the geodynamic evolution of the medium to large-scale structural units, which we can observe today in three dimensions on structural maps, geophysical recordings and digital models. This study concentrates on an area that comprises the southern Northeast German Basin, the Saale Basin, the Flechtingen High, the Harz Mountains High and the Subhercynian Basin. The presented data include re-evaluations of special geological and structural maps, the most recent interpretation of the DEKORP BASIN 9601 seismic profile and observations of exposed rock sections in Northeast Germany. On the basis of different structural inventories and different basement properties, we distinguish two structural units to the south and one structural unit to the north of the Elbe Fault System. For each unit, we propose a geomechanical model of basin formation and basin inversion, and show that the Rhenohercynian Fold and Thrust Belt domain is deformed in a thin-skinned manner, while the Mid-German Crystalline Rise Domain, which is the western part of the Saxothuringian Zone, rather shows a thick-skinned deformation pattern. The geomechanical model for the unit north to the Elbe Fault System takes account to the fact that the base of the Zechstein beneath the present Northeast German basin shows hardly any evidence for brittle deformation, which indicates a relative stable basement. Our geomechanical model suggests that the Permocarboniferous deposits may have contributed to the structural stiffness by covering small to medium scale structures of the upper parts of the brittle basement. It is further suggested that the pre-Zechstein successions underneath the present Northeast German basin were possibly strengthening during the Cretaceous basin inversion, which resulted in stress transfer to the long-lived master faults, as indicated for example by the shape of the salt domes in the vicinity of the latter faults. Contrary to this, post-Zechstein successions deformed in a different and rather complex way that was strongly biased by intensive salt tectonic movements.  相似文献   

Numerical models of tectonic deformation at the Baltica–Avalonia transition zone during the Paleocene phase of inversion     

Anna Maria Marotta  Roberto Sabadini 《Tectonophysics》2003,373(1-4):25

Predictions from dynamic modelling of the lithospheric deformation are presented for Northern Europe, where several basins underwent inversion during the Late Cretaceous and Early Cenozoic and contemporary uplift and erosion of sediments occurred. In order to analyse the evolution of the continental lithosphere, the equations for the deformation of a continuum are solved numerically under thin sheet assumption for the lithosphere. The most important stress sources are assumed to be the Late Cretaceous Alpine tectonics; localized rheological heterogeneities can also affect local deformation and stress patterns. Present-day observations available in the studied region and coming from seismic structural interpretations and stress measurements have been used to constrain the model. Our modelling results show that lateral variation in lithospheric strength below the basin systems in Central Europe strongly controls the regional deformation and the stress regime. Furthermore, we have demonstrated that the geometry of the boundary between Baltica and Avalonia, together with different rheological characteristics of the two plates, had a crucial role on local crustal deformation and faulting regime resulting in the Baltica–Avalonia transition zone from the S–N Alpine convergence.  相似文献   

Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts   总被引：4，自引：0，他引：4  

ZhangBingshan TangLiangjie JinZhijun DaiJunsheng ZhangMingli ZhangBingshan 《中国地质大学学报(英文版)》2003,14(1):65-72

The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;（3）Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt.  相似文献   

利用SV分量接收函数反演地壳横波速度结构   总被引：1，自引：1，他引：1       下载免费PDF全文

邹最红  陈晓非 《地震学报》2003,25(1):15-23

详细讨论了远震体波SV分量接收函数的特点及其在反演地壳S波速度结构中的优势．与径向接收函数类似，SV分量接收函数可通过对远震体波的SV分量直接反褶积P分量获得．研究分析表明:与径向接收函数相比，SV分量接收函数的振幅随震中距的变化更加稳定，波形简单且突出了对结构最敏感的PS转换波信息．理论数值实验显示:在反演地壳S波速度结构时，SV分量接收函数比径向接收函数具有更好的收敛性．作为实例，利用SV分量接收函数反演方法反演了海拉尔台下的S波速度结构．   相似文献