地震拓扑预测     

谭承业  阮圣娜 《地震研究》1989,12(3):193-200

本文对地震参数建立了地震拓扑空间并把灰色系统理论中的拓扑预测方法引入地震预测之中,研究地震长趋势的预测问题。  相似文献   

输水管网模糊地震可靠性的 Monte Carlo 法分析程序     

刘锡荟  王海燕  张锐 《地震研究》1989,(3)

本文详细介绍了笔者所建议的运用模糊图理论和方法进行城市输水管网的地震可靠性分析途径和计算程序。对于输水管网中每段管道的震害预测,建立了相应的专家系统。在此基础上,定义了管网系统的模糊可靠性,更好地反映了人们对于管道损坏状态估计的模糊性和对可靠性要求上的模糊性。以模糊矩阵来描述输水管网的状态是十分方便的。通过计算模糊矩阵的传递闭包,极易找出最短路、关键段等。由于地震作用和管道抗震能力都是随机的,因此整个管网系统的可靠性分析是藉助Monle Carlo法进行的。以Monle Carlo法对模糊图进行分析,从而得到管网的地震可靠性,这还是首次。用PASCAL和PROLOG编制了在微机上实用的计算机程序,特别是以智能语言PROLOG编制的程序,更有许多特色。由于采用了一些技巧,使在微机上可以分析相当大的系统,为城市抗震防灾工作提供了一个有力的工具。  相似文献   

Polar regionSq     

Wen-Yao Xu 《Pure and Applied Geophysics》1989,131(3):371-393

Geomagnetically quiet day variations in the polar region are reviewed with respect to geomagnetic field variation, ionospheric plasma convection, electric field and current. Persistently existing field-aligned currents are the main source of the polar regionSq. Consequently, the morphology and variability of the polar regionSq largely depend upon both field-aligned currents and ionospheric conductivity. Since field-aligned currents are the major linkage between the ionosphere and the magnetosphere, the latter is controlled by solar wind state, in particular, the interplanetary magnetic field, the polar regionSq exhibits remarkable IMF dependence.  相似文献   

Rockburst research at Falconbridge's Strathcona Mine,Sudbury, Canada     

D. M. Morrison 《Pure and Applied Geophysics》1989,129(3-4):619-645

Microseismic systems at five mines in the Sudbury Basin provide the basic data for Falconbridge Limited's rockburst research. Daily and long-term analysis of this data as well as underground observations have confirmed the fault-slip mechanism at three mines. A detailed analysis of the complete history of Falconbridge Mine is being conducted and Distinct Element numerical models are being used to simulate both the stick-slip behaviour of faults and the dynamic effects of the induced vibrations on rock and backfill. University research includes acoustic tomographic imaging of the rock mass based on seismic wave propagation and collection of full microseismic waveforms to allow application of advanced seismic and statistical analysis techniques.Formerly with Mines Technical Services, Falconbridge Limited, Sudbury Operations, Falconbridge , Ont., P0M 1S0.Presented at the Fred Leighton Memorial Workshop on Mining Induced Seismicity, Montreal, Canada, August 30, 1987.  相似文献   

An unusual zone of seismic coupling in the Bonin arc: The 1972 Hachijo-Oki earthquakes and related seismicity     

Tetsuji Moriyama  Fumiko Tajima  Tetsuzo Seno 《Pure and Applied Geophysics》1989,129(1-2):233-261

The 1972 February and December Hachijo-Oki earthquakes (M _s=7.3 and 7.4), in the northernmost part of the Izu-Bonin subduction zone, are the only major events (M _s>7.0) in the Bonin arc for the past 80 years. Relocation of the hypocenters, using one smaller event having a wellconstrained focal depth as a master event, shows that the depth of the February event is 10 km shallower than that of the December event. We have determined the rupture process for both events by minimizing the error in waveform between observed and synthetic seismograms. Although the number of available stations are limited, the depth range of the major energy release for the December event extends deeper than for the February one. The rupture propagated up-dip for both events. It is likely that the rupture zone of the two events overlapped, and that the December event ruptured the deeper part. This suggestion is consistent with the observation that the aftershock zones of both events overlap with that of the December event shifted landward. The waveforms of the December event have a smaller high frequency component than those of the February event, suggesting that the stress at the thrust zone became more uniform or reduced after the February event.No thrust type smaller event occurred near the rupture zone. Instead, theP-axes of smaller events are parallel to the dip of the slab and theirT-axes dip to the southwest. Focal depths of these events estimated byP-wave forward modeling are generally between 40–50 km and located beneath the thrust zone. We thus interpret them as the events within the Pacific slab near the zone ruptured by the two major events. The stress concentration around the rupture zone of the major events is suggested to have triggered these slab events. After the occurrence of the large events, the slab events are concentrated near the deeper portion of the rupture zone. These events may have been caused by the loading of the down-dip compressional stress near the down-dip end of the rupture zone due to the rupture. The occurrence of the doublet of large earthquakes and a number of down-dip compressional events beneath their rupture zones in a shallow portion of the subducting slab indicates an unusual zone of seismic coupling in the Bonin arc, most of which is seismically quiescent.  相似文献   

Subduction and back-arc activity at the Hikurangi convergent Margin,New Zealand     

Euan G. C. Smith  Tim Stern  Martin Reyners 《Pure and Applied Geophysics》1989,129(1-2):203-231

The Hikurangi Margin is a region of oblique subduction with northwest-dipping intermediate depth seismicity extending southwest from the Kermadec system to about 42°S. The current episode of subduction is at least 16–20 Ma old. The plate convergence rate varies along the margin from about 60 mm/a at the south end of the Kermadec Trench to about 45 mm/a at 42°S. The age of the Pacific lithosphere adjacent to the Hikurangi Trench is not known.The margin divides at about latitude 39°S into two quite dissimilar parts. The northern part has experienced andesitic volcanism for about 18 Ma, and back-arc extension in the last 4 Ma that has produced a back-arc basin onshore with high heaflow, thin crust and low upper-mantle seismic velocities. The extension appears to have arisen from a seawards migration of the Hikurangi Trench north of 39°S. Here the plate interface is thought to be currently uncoupled, as geodetic data indicate extension of the fore-arc basin, and historic earthquakes have not exceededM _s=7.South of 39°S there is no volcanism and a back-arc basin has been produced by downward flexure of the lithosphere due to strong coupling with the subducting plate. Heatflow in the basin is normal. Evidence for strong coupling comes from historic earthquakes of up to aboutM _s=8 and high rates of uplift on the southeast coast of the North Island.The reason for this division of the margin is not known but may be related to an inferred increase, from northeast to southwest, in the buoyancy of the Pacific lithosphere.  相似文献   

Laboratory and field investigations of rockburst phenomena using concurrent geotomographic imaging and acoustic emission/microseismic techniques     

R. P. Young  D. A. Hutchins  S. Talebi  T. Chow  S. Falls  L. Farrell  D. Jansen  J. McGaughey  J. Towers  T. Urbancic 《Pure and Applied Geophysics》1989,129(3-4):647-659

The progress made on three phases of a research project, started in 1986 to investigate mining induced seismicity/rockburst phenomena using concurrent geotomographic imaging and microseismic monitoring techniques, is described. Phase I is the geotomographic software development and laboratory calibration trials. Phase II is the enhancement of traditional microseismic monitoring instrumentation with a waveform acquisition system, so that source mechanism studies can be carried out on mining induced seismic events. Phase III is the field trials of the hybrid technique which will be used to monitor changing rock mass physical properties, in response to mining. Preliminary results from all three phases are given, together with an outline of current and future research planned.Presented at the Fred Leighton Memorial Workshop on Mining Induced Seismicity, Montreal 1987.  相似文献   

浅谈阿舍勒黄铁矿型多金属矿的垂直分带   总被引：3，自引：0，他引：3  

陈文鳌  赵云长  吴长江 《新疆地质》1989,(1)

阿舍勒黄铁型多金属矿床位于阿尔泰地槽褶皱系的中泥盆统安山质—英安质火山—沉积岩中.矿体充填在火山管道内或火山口近侧,主矿体隐伏地下.矿化元素有铁、铜、铅、锌、金、银、硫、钡等,伴生有锗、镓、铟、硒、镉、铋等.矿体上部形态复杂并有分枝,向深部连成一体,是一个向北东侧伏的筒状体.矿体自上而下具垂宜分带,依次为:重晶石—硅化带;黄铁矿—多金属带;黄铁矿—铜、锌带等…  相似文献   

断尾沟和断错水系及断错速率的商讨     

刘景元 《内陆地震》1988,(4)

能形成所谓“肘状拐弯”的断错水系,必是先有冲沟,后被断错的水系。而先有断层,后溯源侵蚀发育的冲沟则不能形成”肘状拐弯“的断错水系。因此,断层一侧沟的长度—断尾沟长度与断层年龄无关,最终与断层运动速率之间的关系也不易确定。  相似文献   

(产刂)子坪铀矿床铀—铅同位素演化体系的研究     

徐伟昌  黄世杰  夏毓亮 《华东地质学院学报》1988,(1)

铲子坪铀矿床是产在下寒武统清溪组地层中受含矿层及层间构造双重因素控制的矿床。根据该矿床中各种岩石、矿石及矿物的铀—铅同位素体系的研究,大多数岩石样品的铀—铅同位素组成明显不平衡,据计算,含矿层及周围花岗岩中的铀主要以丢失为主,丢失量为30—80％。富矿石的一致性图解及铀—铅三阶段模式年令为t_1=523±16M.Y.,t_2=22±2M.Y.。沥青铀矿的等时线年令为75±4M.Y.,43±7M.Y.。岩石年令为416M.Y.。上述结果表明矿床中的铀主要由含矿层本身供给;可以区分出三个成矿阶段:沉积成岩的予富集,加里东期动力变质的初富集和燕山晚期——喜山早期渗流热液的再富集,因而本矿床属沉积再造的层控铀矿床。  相似文献