Surface fault traces,fault plane solution and spatial distribution of the aftershocks of the September 13, 1986 earthquake of Kalamata (Southern Greece)

A shallow earthquake ofM _S=6.2 occurred in the southern part of the Peloponnesus, 12 km north of the port of the city of Kalamata, which caused considerable damage. The fault plane solution of the main shock, geological data and field observations, as well as the distribution of foci of aftershocks, indicate that the seismic fault is a listric normal one trending NNE-SSW and dipping to WNW. The surface ruptures caused by the earthquake coincide with the trace of a neotectonic fault, which is located 2–3 km east of the city of Kalamata and which is related to the formation of Messiniakos gulf during the Pliocene-Quaternary tectonics. Field observations indicate that the earthquake is due to the reactivation of the same fault.A three-days aftershock study in the area, with portable seismographs, recorded many aftershocks of which 39 withM _S1.7 were very well located. The distribution of aftershocks forms two clusters, one near the epicenter of the main shock in the northern part of the seismogenic volume, and the other near the epicenter of the largest aftershock (M _S=5.4) in the southern part of this volume. The central part of the area lacks aftershocks, which probably indicates that this is the part of the fault which slipped smoothly during the earthquake.     

永平铜矿床中钼矿的矿源与成矿

本文论述了永平铜钼矿床的矿质来源主要来自于混合岩化作用以前形成的原始含矿地层;其成矿是由于变生热液在动力和热力作用下,萃取了己被混合岩同化的矿源层中的矿质,形成含矿的变生热液,在迁移过程中,选择在矿源层残留块体或其毗邻地段,形成愿地、半原地的由含矿变生热液迭加而富集的铜、钼矿体.     

化学动力学在地球化学中的某些应用

化学动力学在地球化学（特别是成矿作用地球化学）研究中有极其重要的作用,其主要应用包括七个方面。本文重点介绍了地球化学中化学动力学的实验研究方法以及碳酸盐、硅酸盐、氧化物和硫化物等矿物的反应动力学实验成果;介绍了Helgeson的质量迁移理论及其研究热液在围岩中的运移方面的应用,并在热力学性质和动力学行为两方面研究了围岩的离解作用、蚀变作用与矿化作用及其相互关系。     

Evidence for transform faulting in the Ionian sea: The Cephalonia island earthquake sequence of 1983

Accurate locations of aftershocks of the January 17, 1983 (M _s=7.0) main shock in the Ionian islands have been determined, as well as fault plane solutions for this main shock and its largest aftershock, which are interpreted as a right-lateral, strike-slip motion with a thrust component, on a fault striking in about a NE-SW direction.This is considered as a transform fault in the northwesternmost part of the Hellenic arc.     

Electron paramagnetic resonance characteristics of the humic acids from a podzol

A study has been made of solid and solution electron paramagnetic resonance (EPR) spectra of humic acids from different horizons in a podzolic soil. Hyperfine splitting was observed in the solution spectra of humic acids from all horizons and depended on the strength of alkali and the period of dissolution. The upper organic horizons L, F and O₁ contained humic acids with some spectral characteristics in common with lignin. Humic acid from the lower horizons showed different spectra. At least 5 different radical signals were present.     

The structure of chaos in a potential without escapes

We study the structure of chaos in a simple Hamiltonian system that does no have an escape energy. This system has 5 main periodic orbits that are represented on the surface of section by the points (1)O(0,0), (2)C ₁,C ₂(±y _c, 0), (3)B ₁,B ₂(O,±1) and (4) the boundary . The periodic orbits (1) and (4) have infinite transitions from stability (S) to instability (U) and vice-versa; the transition values of are given by simple approximate formulae. At every transitionS U a set of 4 asymptotic curves is formed atO. For larger the size and the oscillations of these curves grow until they destroy the closed invariant curves that surroundO, and they intersect the asymptotic curves of the orbitsC ₁,C ₂ at infinite heteroclinic points. At every transitionU S these asymptotic curves are duplicated and they start at two unstable invariant points bifurcating fromO. At the transition itself the asymptotic curves fromO are tangent to each other. The areas of the lobes fromO increase with ; these lobes increase even afterO becomes stable again. The asymptotic curves of the unstable periodic orbits follow certain rules. Whenever there are heteroclinic points the asymptotic curves of one unstable orbit approach the asymptotic curves of another unstable orbit in a definite way. Finally we study the tangencies and the spirals formed by the asymptotic curves of the orbitsB ₁,B ₂. We find indications that the number of spiral rotations tends to infinity as . Therefore new tangencies between the asymptotic curves appear for arbitrarily large . As a consequence there are infinite new families of stable periodic orbits that appear for arbitrarily large .     

3-D rheologic model of earthquake preparation (Ⅱ):Strain field and its applications

On the basis of the three-dimensional elastic inclusion model, the analytic expression of viscoelastic strain field is derived, i.e., the analytic expression of viscoelastic strain at an arbitrary point (x, y, z) in x-axis, y-axis and z-axis produced by three-dimension inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model, namely the normal strains εxx(r, t), εyy(r, t) and εzz(r, t), the shear strains εxy(r, t) and εyx(r, t), εyz(r, t)and εzy(r, t), εxz(r, t) and εzx(r, t), and the bulk-strain θ (r, t). By computing the spatial-temporal variation of bulk strain on the ground produced by a spherical rheologic inclusion in a semi-infinite rheologic medium, we obtained some significant results that the bulk-strain variation with time produced by a hard inclusion has three stages (α, β,γ) with different characteristics, which are similar to those of most geodetic deformation curves, but not the case for those by a soft inclusion. It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial-temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short-term and imminent-term precursors. It offers a theoretical base to found the physical model of earthquake precursors and a reference to predict physically the earthquakes.     

由GPS观测结果推断中国大陆活动构造边界

利用“中国地壳运动观测网络”基本网1998年和2000年两期观测数据,得到分布在全国各构造块体上的79个GPS观测站速度场，对中国大陆主要活动构造块体间的相对运动显著性进行了分析和检验. 分析结果表明，西部活动构造块体的边界有较明显的相对运动，而东部运动不明显. 根据分析得到的活动边界，将中国大陆归并为11个活动块体，逐一计算了这些块体边界的活动量大小，确定了它们最新活动的方式.