THE QIONGHAI CRUSTAL TILT OBSERVATION SYSTEM AND THE SEISMIC ACTIVITY IN WESTERN SICHUAN PROVINCE, CHINA

In this paper, we introduce the measurements of crustal tilt using the Qionghai Observation System and a preliminary approach to the relation between the crustal plane tilt observed by the System and seismic activity in the region around the Qionghai Lake, at Xichang.The results show that the observed accuracy may reach the magnitude of 10-7-10-8 radian. The processes of the crustal stress accumulation and release are characterized by the activity of moderate earthquakes (M≥5.0) whose     

柴达木盆地及邻区主要活动断裂及其与地震的关系

本文根据野外调查资料及重力、航磁等资料,对柴达木盆地及其邻区的主要活动断裂的大地构造位置、产状、深度和第四纪活动特点等进行了分析研究,並讨论了这些断裂与地震活动的关系。这一地区的地震活动强度与断裂深度有关,具左旋运动特征的全新世近东西向活断层与强地震活动的关系最为密切。     

北京地区新构造运动特征

根据北京地区构造演化、断裂活动、新构造运动、现代构造运动及地震活动等新资料,认为本区南、北段新构造运动特征存在明显差异,南段新构造活动较北段弱,未来地震危险性亦然     

Petrochemistry,Age and Petrogenesis of the Shexian Pluton in Southern Anhui

The Shexian gneissic granodiorite in southern Anhui trends NE 55° from Shexian in the west to Guitoujian in the east with a length of 22 km and an outcrop area of 32 km. It was considered formerly to be Caledonian on the basis of a biotite K-Ar age of 474 Ma (1982). However, new evidence indicates that it may be Early Jinning in age as shown by: (1) it is found intruding into the Mid-Proterozoic Shangxi Group and is unconformably overlain by the Sinian Xiuning Formation, and (2) a zircon U-Th-Pb age of 928 Ma is obtained for the pluton. The pluton is composed of plagioclase (An=27.37%), K-feldspar(14%), biotite(16%) and quartz(32%). Accessory minerals are ilmenite (150g/T), xenotime (15g/T). garnet(25g/T), monazite(10g/T), zircon (20g/T) and apatite (104g/T). Petrochemical characteristics of the intrusion are:(l) Al-enrichment (A/NKC=1.30); (2) H₂O enrichment (H₂O= 1.74%); and (3) low oxidation index (f ’=0.10). It belongs to the continental crust transformation type as evidenced by: (1) MF and Mg/Y values of biotite are 0.41 and 0.31 respectively; (2) (⁸⁷Sr/⁸⁶Sr)=0.71119; (3) δ Eu=0.52; and (4) A/NKC=130. The Shexian pluton is therefore considered as a product of melting of phyllite at depth in the light of similarities in trace element and REE contents with the phyllite of the Banxi Group. Calculations of REE batch partial melting indicate that it may have resulted from 75% melting of the Banxi phyllite.     

永胜倾斜潮调和分析结果及其与地震的关系

本文利用永胜台水管倾斜仪观测资料分别进行了资料长度为１月和１年的维尼迪科夫调和分析。研究了振幅因子与地震的关系，发现地震前ＥＷ２分量Ｍ２波与ＮＳ分量Ｏ１波的γ值具有不同程序的异常变化，异常量为１．５％－７．７％；在地震发生前或地震发生时，各个主潮波γ值误差变大。用震例分析证明了倾斜固体潮振幅异常用于地震预报的可行性。     

干法毛管压力试验新技术及其在判别储层水饱和度中的应用

根据毛细管压力理论研制的ＹＢ－１型岩石水饱和度仪，广泛应用于油气勘探开发中测定储集岩石的含水饱和度，测定误差小于５％，该方法为不受取心条件、样品大小、物性和岩性限制快速的新方法，实际应用证明效果较好     

新疆塔城地区地震地质特征

托里活断层、达尔布特活断层、独山子—安集海活断层及霍尔果斯—卡子湾活断层是塔城地区主要的全新世活断层，均有过多次古地震活动。自１９７７年以来，４级以上地震活动的空区在裕民县西北。据活断层古地震活动复现期及地震活动围空特点分析，今后１０年北天山或塔城西北可能有发生６级左右地震的危险。     

民乐盆地某些活断层断层泥中石英颗粒的表面特征及其地震地质意义

本文对民乐盆地三条活动断层断层泥内石英颗粒表面的显微构造作了较系统的研究。根据这些石英颗粒表面特征对该区莺落峡等断层的滑动性质和断层活动的相对年代进行了讨论。提出了以下的新看法:莺落峡断层的中段为粘滑段,东西两段为蠕滑段,古震源在该断层的黑河口一带,发生的时代大致在晚更新世晚期或全新世早期;茨湖断层具有最新活动特征,粘滑标志明显。另外清水沟老断层在全新世时也有新活动。