Study of crustal structure with S—wave data from Maqen—Jingbian profile     

刘宝峰  李松林  张先康  张成科  任青芳  海燕 《地震学报(英文版)》2003,16(1):92-98

2-D crustal velocity structure and vp/vs are obtained by processing and interpretation of S-wave data from Maqen-Jingbian deep seismic sounding(DSS)profile.The result shows that there exist obvious differences in 2-D S-wave velocity structure and vp/vs ratio structure along the profile.The S-wave velocities are low and vp/vs ration is high for the westem section of the profile and Haiyuan region,while they are normal for the middle and eastern sections.The changes in lithologic characters of two major anomalous zones are discussed according to lateral variation of S-wave velocity structure and vp/vs ratio structure.It is concluded that the development and occurrence of the Haiyuan strong earthquake is not only related to tectonic activities,but also to lithologic characters of the region.  相似文献   

石泉ML4．7级地震前天水深井水温的短临异常特征     

缑亚江刘东升  何松毅周建强 高曙德 《高原地震》2003,15(4):45-51

分析了天水台数字深井水温资料在陕西石泉ML4．7级地震前的异常特征，发现在震前5天内深井水温发生大幅度的降升变化，呈负脉冲形态，表现为典型的脉冲型前兆异常形态特征。  相似文献   

Lithospheric structure and continental geodynamics     

许忠淮  石耀霖 《地震学报(英文版)》2003,16(5):544-560

This paper briefly reviews main progress in the research on lithospheric structure and continental geodynamics made by Chinese geophysicists during last 4 years since 22nd IUGG general assembly in July 1999. The research mainly covers the following fields: investigations on regional lithospheric structure, DSS survey of crust and upper mantle velocity structure, study on present-day inner movement and deformation of Chinese mainland by analyz-ing GPS observations, geodynamics of Qingzang plateau, geophysical survey of the Dabie-Sulu ultra-high pressure metamorphic belt and probing into its formation mechanism, geophysical observations in sedimentary basins and study on their evolution process, and plate dynamics, etc.  相似文献   

Crustal structure beneath the Songpan—Garze orogenic belt   总被引：2，自引：0，他引：2  

王椿镛  韩渭宾  吴建平  楼海  白志明 《地震学报(英文版)》2003,16(3):237-250

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   

慕士塔格冰芯钻孔温度测量结果   总被引：1，自引：2，他引：1  

邬光剑  姚檀栋  徐柏青  李真  保翰璋 《冰川冻土》2003,25(6):676-679

2002年8月对慕士塔格冰川累积区海拔6300m左右的两根冰芯钻孔(其中—根达到冰川底部基岩)进行了温度测量，揭示了该处冰川的温度分布特征．结果表明：慕士塔格冰芯的冰温是目前中低纬地区山地冰川中最低的，达-21．79℃，该最低温度出现的位置在35m以下；冰床底部的温度为-20．76℃，也远低于其它山地冰川的冰床温度，极低的温度对成冰过程有重要影响，并有利于获得可靠的冰芯记录。  相似文献   

西北干旱区深层岩溶地下水系统的水化学-同位素研究--以宁南“南北古脊梁”岩溶水系统为例   总被引：9，自引：0，他引：9  

李向全  张莉  于开宁 《吉林大学学报(地球科学版)》2003,33(4):524-529

运用构造控水分析、水化学同位素等方法，对宁南“南北古脊梁”岩溶裂隙水系统进行了深入的分析与讨论。本区储水空间以岩溶裂隙为主，岩溶水的空间分布明显受南北向大型断裂构造控制。岩溶地下水以大气降水起源为主，并表现为多元水混合。水质分布呈南优北劣的分带特征，北部水-岩相互作用形式为溶滤-蒸发浓缩型，呈高矿化咸水；南部为溶滤-混合型，呈低矿化淡水。根据水动力场和水化学场特征，划分了3个相对独立的岩溶水子系统。  相似文献   

中国油气储层地质研究面临的挑战和发展方向   总被引：36，自引：6，他引：36  

罗平  裘怿楠  贾爱林  王雪松 《沉积学报》2003,21(1):142-147

论述了我国采取“稳定东部 ,发展西部”的油气战略后 ,油气地质所面临的形势 ,以及油气工业的发展对储层地质提出四个领域的挑战 :深部储层、挤压盆地储层、低渗透储层和碳酸盐岩储层 ;这些都是石油勘探开发中久攻不克的难题。根据我国陆上东西部油气区的勘探开发实际和近年的储层研究实践 ,文章系统多视角地分析了这四个难题 ,并提出了相应客观的研究思路和研究方向。  相似文献   

含柯石英超高压榴辉岩的早期变形--以苏北东海碱场榴辉岩体为例   总被引：2，自引：0，他引：2  

索书田  杨启军  钟增球  周汉文  游振东 《地质科技情报》2003,22(4):1-8

以超高压矿物组合的各种后成合晶及冠状体等卸载不平衡结构为参考标志，将含柯石英的超高压榴辉岩的交形序列分成两个部分。后成合晶及冠状体发育之前的变形为早期变形，是在大陆深俯冲和碰撞条件下发育的超高压变质变形组构。后成合晶及冠状体发育之后的变形为晚期变形，是在超高压岩石折返剥露过程中，主要是在角闪岩相甚至绿片岩相条件下发育的。构造上江苏省北部东海县碱场合柯石英榴辉岩体，分为块状榴辉岩和面理化榴辉岩两种类型，分别代表超高压变质岩早期变形的两个构造阶段或世代(D1、D2)。详细描述了它们的矿物组合、中小尺度及显微尺度下的组构特征，讨论了两者的几何关系和区域构造意义，强调指出，只有含柯石英榴辉岩的早期变形组构，才能记录和反映斜向大陆深俯冲及碰撞的动力学过程。  相似文献   

松辽盆地形成与演化的深部作用过程--中生代火山岩探针   总被引：7，自引：0，他引：7  

王清海  许文良 《吉林大学学报(地球科学版)》2003,33(1):37-42

松辽盆地中生代火山作用从一个侧面揭示了松辽盆地形成与演化历史。松辽盆地中生代火山岩的岩石地球化学研究表明，中生代火山作用的深部过程表现为岩浆源区从逐渐上升到下降的过程。晚侏罗世到早白垩世早期为降温降压过程，表现为等温面逐渐升高，岩石圈伸展速度增大，岩浆源区变浅，盆地演化由断焰向坳陷转化。从早白垩世早期到晚白垩世，则为升温升压过程，等温面下降，岩石圈伸展速度变小，岩浆源区加深，盆地演化进入坳陷期。  相似文献   

停止开采深层地下水 修复与改善生态环境     

刘俊龙  范振铎 《地下水》2003,25(2):75-76,105

沧州市水资源短缺，深层地下水严重超采，已形成大面积区域地下水位降落漏斗，地面沉降已达2m，生态环境严重恶化．为保障经济社会的可持续发展，要积极引调地表水，开发利用地下咸水，加强雨洪控制利用，逐步替代最后终止深层地下水的开采。从根本上修复和改善生态环境。  相似文献