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201.
Kan Rongju Hu HuiSeismological Bureau of Yunnan Province Kunming ChinaYunnan Astronomical Observatory Academia Sinica Kunming China 《中国地震研究》1996,(3)
In this paper,the features of medium-term anomalies for strong earthquakes and the criteria for the prediction of such earthquakes are discussed,as well as the feasibility of applying the anomalies of astronomical time-latitude residuals to earthquake prediction and their limitation when applied to imminent-term prediction.The criteria used to identify the anomalies of time-latitude residuals for M≥6.0 earthquakes in Yunnan Province and for M≥7.0 earthquakes around Yunnan are also discussed.The last strong earthquake in the data used for testing passed the whole process of earthquake prediction practice.In addition,some special features of the case in which anomalies appeared but no strong earthquake followed are also discussed. 相似文献
202.
In this paper,the temporal and spatial variation process of seismicity in areas from Lancang to Tengchong before the 1988 Lancang-Gengma earthquakes(M=7.6,7.2),January 1980 to October 1988,is studied in detail according to the theory that the whole process of earthquake sequence in the time stage of anomalous seismicity before a strong event may be considered as the non-homogeneous Poisson process.The results demonstrate that(1)from April 1985 to April 1988,there existed an obvious difference of seismicity in spatial distribution in the whole region; to the north of Lancang,there occurred two seismic quiescent belts:one is 210 km long for M≥3.5 events and anotheris 160 km long for M≥3.0 events; therefore,this may be classified into four sub-regions from south to north,that is,the south region,the mid-region,the mid'-region,and the north region.(2)Before the mainshocks,there existed anomalous seismic quiescence for as Song as 42 months in the mid-region(M≥3.5)and 32.5 months in the mid'-region(M≥3.0) 相似文献
203.
Liu Wenlong Wu Peizhi and Chen YuweiSeismological Bureau of Annul Province Hefei China 《中国地震研究》1996,(3)
In this paper,a new method for determining the earthquake fracture feature is put forward.The generalized directional function DG is defined as the ratio of P waveamplitude spectrums recorded at station 1 and station 2 by comparisonof the recorded DG curve and the theoretical curve,the ratio of fracture lengths of a bilateral fracture in two opposite directions and the angle between station 1 and the main rupture propagating direction can be determined simultaneously.Theoretically speaking,only records of three stations distributed homogeneously are needed to determine the fracture feature of an earthquake.The main rupturing propagating direction of a strong aftershock(ML5.4)of the Tangshan earthquake(Ms7.8)has been obtained by using the new method and has been compared with the result of the earthquake source mechanism.This shows that this new method is effective. 相似文献
204.
腾冲——勐海共轭地震构造带 总被引:2,自引:0,他引:2
使用地震和地质资料的综合分析方法研究了腾冲一勐海地区地震破裂特征,结果认为:本区存在长400km,宽45km的地震构造带,它是由一条长400km,宽25km的NNW向右旋剪切带为主干和几条NE-NEE向左旋走滑断裂变切而成的共轭地震构造带.带内地震具有线性排列和统一的周期性活动. 相似文献
205.
华北平原沉降地区重力场变化分析 总被引:2,自引:1,他引:2
华北平原沉降带相对于西部太行山区,近几年观测到的重力值相对1989年同期呈上升状态、其中某些地区累计上升量相当大,比如,沧州地区达143×10~(-8)m/s~2,任丘地区103×10~(-8)m/s~2,巨鹿—南宫为(89—103)×10~(-8)m/s~2.对某些地区的重力变化量进行地下水下降量和地面沉降量校正,其校正量可达到变化量的1/3—1/2.校正后的重力值变化幅度减小,但有些异常依然存在.这种较大的剩余变化量,可能含有两个因素:其一可能与华北平原沉降带的继承性下降及某些地区构造断裂活动有关;其二可能是实际地面沉降量比推测的沉降量大. 相似文献
206.
日偏食对低纬地磁场的影响 总被引:1,自引:0,他引:1
1995年10月24日日偏食期间,我们在海南省琼中进行了地磁场总强度的观测和分析,同时运用该地磁台三分量磁照图,分析了地磁D场D、H、Z三分量在日偏食期间的变化特征。结果表明:日偏食期间,磁偏角初亏后逐渐偏东,食甚后偏西;水平强度和总强度初亏后逐渐变小,食甚后上升;垂直强度初亏后逐渐变大,食甚后约1个小时变小。 相似文献
207.
用文献(贺仲雄,1983)提出的一种模糊综合评判方法,对内蒙布特哈旗一带进行了地震年度预报研究。利用1971~1988年共18年观测资料作为样本资料,对后17年进行预报检验,取得了较好的结果。 相似文献
208.
In this work,the fractal dimension of granulometric composition in the fault gouge from the Yishu fault zone and northwest-trending faults on its west side is calculated and studied based on the fractal theory of rock fragmentation.The seismo-geological implications of the fractal dimension of granulometric composition in fault gouges are also discussed.The results show that the Yishu fault zone is more active than the northwest-trending faults and the Anqiu-Juxian fault is the most active in the Yishu fault zone.The fractal dimension of fault gouge is a parameter describing the relative active age and rupture mode of the fault and forming age of the fault gouge.The fractal dimension value is also related to the parent rock,thickness,structural position,and clay content of the fault gouge. 相似文献
209.
210.
笔者等在海南岛兰洋地区发现了丰富的石炭系孢子,计38属64种。其中,产于青天峡组上部的孢子组合,与G.Clayton等人所建立的“PU“带相当,属韦宪期早期。产于石岭组下部的孢子组合,则具有韦宪期中晚期的色彩。这些孢子的发现,为该区石炭系的划分与对比提供了重要依据,同时也有助于探讨海南岛大地构造的某些问题。作者依据孢子组合及其伴生的植物化石,对石炭纪广东大陆与海南岛分属两个地体的看法提出了质疑,而 相似文献