Specific variations of air temperature and relative humidity around the time of Michoacan earthquake M8.1 Sept. 19, 1985 as a possible indicator of interaction between tectonic plates

The recent development of the Lithosphere–Atmosphere–Ionosphere (LAI) coupling model and experimental data of remote sensing satellites on thermal anomalies before major strong earthquakes have demonstrated that radon emanations in the area of earthquake preparation can produce variations of the air temperature and relative humidity. Specific repeating pattern of humidity and air temperature variations was revealed as a result of analysis of the meteorological data for several tens of strong earthquakes all over the world. The main physical process responsible for the observed variations is the latent heat release due to water vapor condensation on ions produced as a result of air ionization by energetic α-particles emitted by ²²²Rn. The high effectiveness of this process was proved by the laboratory and field experiments; hence the specific variations of air humidity and temperature can be used as indicator of radon variations before earthquakes.We analyzed the historical meteorological data all over the Mexico around the time of one of the most destructive earthquakes (Michoacan earthquake M8.1) that affected the Mexico City on September 19, 1985. Several distinct zones of specific variations of the air temperature and relative humidity were revealed that may indicate the different character of radon variations in different parts of Mexico before the Michoacan earthquake. The most interesting result on the specific variations of atmosphere parameters was obtained at Baja California region close to the border of Cocos and Rivera tectonic plates. This result demonstrates the possibility of the increased radon variations not only in the vicinity of the earthquake source but also at the border of interacting tectonic plates. Recent results on Thermal InfraRed (TIR) anomalies registered by Meteosat 5 before the Gujarat earthquake M7.9 on 26 of January 2001 supports the idea on the possibility of thermal effects at the border of interacting tectonic plates.     

火山活动与沉积盆地的形成和演化

我国大陆地壳进入中生代以来,发生了较其他陆壳更为强烈的构造运动,印支,燕山,喜马拉雅运动都是发生在我国大陆地壳以裂陷作用为主的典型运动,在中生代板块构造的特定时代和以裂陷作用主主的构造运动作用下,岩浆活动沿断穿骨石圈和地壳的深断裂发生,上涌至地壳地面形成火山岩带和地层格架中的火山岩层,上涌至地壳内部形成壳内流体相央浆房而成为高导层,火山活动是由中生代生成的太平洋板块和我国大陆地壳俯冲,使大陆地壳深     

岩体结构面水力学模型及应用

本文提出岩体结构面适应性平行板模型和该模型的参数确定方法——三段压水试验新解释,新的模型有益于克服将结构面圆盘模型应用于地下水模拟中的局限性;基于结构面起伏度对地下水流动的影响,导出了起伏度修正系数解析表达式。     

元古宙蛇绿岩研究现状及其板块构造意义

在回顾元古宙蛇绿岩研究简史的基础上,对元古宙蛇绍岩的时空分布特征,岩石组合类型,变质作用程度,大地构造背景及源区地球化学制约等进行了系统总结,并就元古宙蛇绿岩的板块构造意义作了探讨。     

A note on the relationship between dip-slip fault parameters and plate parameters in the two-dimensional modelling of preseismic deformation

Preseismic lithospheric deformation at a subduction zone can be modelled as dip-slip dislocation on an inclined fault or as flexure of a thin plate. Both these models predict a region of positive topography known as forebulge or outer rise. By matching the location and the magnitude of the forebulge, we derive useful relations between the dip-slip fault parameters and the plate parameters. In particular, we determine the width of a long dip-slip fault of given dip corresponding to a semi-infinite plate of given thickness. The displacement profiles of the two models are also compared.     

Analysis of Error Caused by Replacing Spherical Shell with an Elastic Plate Model in Studying Bending Deformation of the Lithosphere

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Heat flow in Italy

More than fifty heat flow measurements in Italy are examined. The values, corrected only for local influences (when present), are related to the main geological features with the following results: foreland areas, 55±19 mW m^–2, foredeep areas, 45±21 mW m^–2; folded regions and intermountain depressions, 76±29 mW m^–2. In volcanic areas the heat flow rises to in excess of 600 mW m^–2. From a tectonic point of view, these values are consistent with the hypothesis that the Apennine chain is intersected by two arcuate structures: the first from Liguria to Latium is very probably a continental arc, that is an are which occurs within a continent, and the second from Campania to Calabria is very similar from geophysical evidence to the classic island arcs.     

天文底片保存和我国天文底片数字化的建议

阐述了国际上天文照相底片数字化工作的进展:底片的保存、底片数字化的意义和相关技术。扼要地介绍了国际虚拟天文台的情况及其与底片数字化的关系。分析了我国天文底片资料的保存现状,并提出了底片数字化建议:成立由各天文台专家组成的全国底片数字化协调小组,建立各单位保存底片的信息库、改进底片的保存条件、有步骤地对有价值底片上的全部目标进行扫描,以便将其与现代高精度的观测资料相结合,开展有意义的课题研究。     

Metamorphic evolution of the Naga Hills eclogite and blueschist, Northeast India: implications for early subduction of the Indian plate under the Burma microplate

Tectonic slices and lenses of eclogite within mafic and ultramafic rocks of the Early Cretaceous–Eocene Naga Hills ophiolite were studied to constrain the physical conditions of eastward subduction of the Indian plate under the Burma microplate and convergence rate prior to the India–Eurasia collision. Some of the lenses are composed of eclogite, garnet-blueschist, glaucophanite and greenschist from core to margin, representing a retrograde hydrothermal alteration sequence. Barroisite, garnet, omphacite and epidote with minor chlorite, phengite, rutile and quartz constitute the peak metamorphic assemblage. In eclogite and garnet-blueschist, garnet shows an increase in Mg and Fe and decrease in Mn from core to rim. In chlorite in eclogite, Mg increases from core to rim. Inclusions of epidote, glaucophane, omphacite and quartz in garnet represent the pre-peak assemblage. Glaucophane also occurs profusely at the rims of barroisite. The matrix glaucophane and epidote represent the post-peak assemblage. The Fe³⁺ content of garnet-hosted omphacite is higher than that of matrix omphacite, and Fe³⁺ increases from core to rim in matrix glaucophane. Albite occurs in late stage veins. P – T pseudosection analysis indicates that the Naga Hills eclogites followed a clockwise P – T path with prograde metamorphism beginning at ∼1.3 GPa/525 °C and peaking at 1.7–2.0 GPa/580–610 °C, and subsequent retrogression to ∼1.1 GPa/540 °C. A comparison of these P – T conditions with numerical thermal models of plate subduction indicates that the Naga Hills eclogites probably formed near the top of the subducting crust with convergence rates of ∼ 55–100 km Myr⁻¹, consistent with high pre-collision convergence rates between India and Eurasia.