Aseismio fault slip and block deformation in North China

In North China, the tectonic fault-block system enables us to use the Discontinuous Deformation Analysis (DDA) method to simulate the long-term cross-fault survey and other geodetic data related to aseismic tectonic deformation. By the simulation we have found that: (1) Slips on faults with different orientation are generally in agreement with the ENE-WSW tectonic stress field, but the slip pattern of faulting can vary from nearly orthogonal, to pure shear along the strike of the faults, this pattern cannot be explained by simple geometric relation between the strike of the fault and the direction of the tectonic shortening. This phenomenon has been observed at many sites of cross-fault geodetic surveys, and might be caused by the interactions between different blocks and faults. (2) According to the DDA model, if the average aseismic slip rate along major active faults is at the order of several tenths of millimeter per year as observed by the cross-fault geodetic surveys, the typical strain rate inside a block is at the order of 10^–8 year^–1 or less, so that the rate of 10^–6 year^–1, as reported by observations in smaller areas, cannot be the representative deformation rate in this region. (3) Between the slips caused by regional compression and block rotation, there is a possibility that the sense of slip caused by rigid body rotation in two adjacent blocks is opposite to the slip caused by the tectonic compression. But the magnitude of slip resulting from the tectonic compression is much larger than that due to the block rotation. Thus, in general, the slip pattern on faults as a whole agrees with the sense of tectonic compression in this region. That is to say, the slip caused by regional compression dominates the entire slip budget. (4) Based on (3), some observed slips in contradiction to ENE tectonic stress field may be caused by more localized sources, and have no tectonic significance.     

鄂尔多斯及其周缘地热分布的某些特征

利用鄂尔多斯及其周缘的大地热流、地温梯度和地温分布等资料研究了其展布特征和差异性变化，并讨论了地热分布与地壳深浅构造的关系。认为，鄂尔多斯块体内大地热流、地温梯度值整体偏低，而其周缘地区则呈现出环状高值异常带。该区地震活动主要集中分布在鄂尔多斯周缘地区，即鄂尔多斯周缘存在着高热流、高地温梯度和地震丛集分布相统一的现象。这一现象说明，地热和地震活动之间存在着某种必然的联系。     

Tectono-Sedimentary History of Southeastern Coast Region,China:a Synthesis

According to the ideas and concepts of systems dynamic of continent structure, using previous information related to the study area, combining analyses on orogenic belt, basin and magmatic rock, the present paper synthesizes the tectono-sedimentary development of southeastern coast region, China, with special emphasis on the mountain making, basining and magmafc activity. The tectonic evolution after Late Caledonian orogeny was dominated by alternating rifting and converging, subsiding and uplifting, mountain making and basining in central and southern parts of southeastern China and the adjacent regions to the east and west. Seventeen geologic events, nine events of plate or terrain convergence , and continental crust accretion, as well as eight events of intracontinental rifting and basin faulting , are closely related to the tectonic and sedimentary evolution of the study area. The accompanied intense and frequent sedimentation , folding , faulting , magmatism and ore-forming process allowed huge coal     

武夷山古环境的变迁与土壤发育的关系

在综合研究了武夷山主峰黄岗山的地质、地貌、植被、气候及第四纪孢粉分析资料后认为,黄岗山在晚第三纪至第四纪的数百万年间,曾经历了至少三次断块抬升运动,每次抬升幅度300—400m,总上升量可达千米之巨。黄岗山的土壤之所以在若干重要分类指标上产生变异,其原因很可能是古环境遗留的特征仍居主导地位,近代成土作用只不过是在原来脱硅富铝化基础上的附加成土过程。     

中国大陆及其周边块体的现时运动、变形及其动力学解释

运用块体不连续变形分析方法 ,对利用GPS测量数据解算中国大陆及其周边块体的位移进行分析。结果显示 ,除块体 2、10、13为近东西方向的运动 ,块体 15为近北东向的运动外 ,其余块体均朝南东或南东东方向运动。同时 ,各块体还以各自的角速度绕其重心旋转。整个研究区在南北方向是压缩的 ,所得的最大主应力方向与利用震源机制解与原地应力测量的结果总的来说大体一致。最后 ,对产生中国大陆及周边块体运动与变形的动力源进行了讨论     

准噶尔海槽西准噶尔地段板块构造演化特征

准噶尔地块为前震旦纪地块。古生代,本区进一步演化成为一个由大陆裂谷发育起来的不成熟洋壳——准噶尔海槽。该海槽向西可与苏联巴尔喀什相通,并将哈萨克斯坦古板块肢解为南、北两大陆块。早石炭世末,本区结束了洋壳历史,重新成为大陆克拉通,托里北——达拉布特一线为缝合线位置。中石炭世以后,以碰撞后构造为主导,发生过三次明显的块断运动和A型俯冲。北东向的达拉布特断裂系就是在本区地壳缩短的背景下产生的走滑断层和推覆构造     

川青块体及其向南东方向运动的新证据

根据近二十年地震活动性、震源机制、活断层及深部探测等方面研究进展提供的新证据,进一步论证了笔者(1980)提出的由鲜水河断裂带、舒尔干—花石峡断裂带、岷江断裂带和龙门山断裂带围限的川青地壳块体的存在及其向南东方向运动的合理性。     

Basic characteristics of active tectonics of China

Active tectonics is inferred to all the structures which have been active since the late Pleisto-cene, 100—120 ka B.P., are still active recently, and will be active in a certain time period in the future, such as active faults, active folds, active basi…     

厦门旧城建设步行街区的初步研究

以厦门旧城区西南部为例,对商业街土地利用和商服业现状作了详尽的调查和分析,在阐述旧城区商业街存在总体地位下降,以服装店为主的零售商业功能过于突出,购物环境容量不足等现实问题的基础上,提出以“步行街区”作为厦门旧城商业街更新发展的对策,并据此对步行街区建设涉及到的部分问题进行了探讨。     

卫星摄影三线阵CCD影像的EEP法空中三角测量（三）

4 平差方案及模拟数据平差实验4.1 自由网+控制点空中三角测量由前方交会(2.1)式,后方交会(2.2)式以及外方位元素平滑制约条件(2.3)式,可以构成类似经典的光束法空中三角测量,但由于EFP像点坐标是推算出来的,所以控制点不宜直接参与平差过程.于是平差要分成自由网平差及利用控制点作三维线性变换两个步骤.另一方面,卫星摄影中起始角元素大约在±0.5°左右,对于经典空中三角测量,角元素起始近似值均可按零处理.但在EFP平差中,φ角起始值φ0对空中三角测量,像元素起始近似值均可按零处理.在EFP平差中,φ角起始值φ0对整条航线的几何状态影响很大,必须采用特殊的程序预先加以确定.我们采用不断步进φ角值,比较由前方交会及(1.2)式计算的Y视差的均方根值最小者,即作为φ的最佳起始值.平差框图见图4.