云南元江地区铜矿GIS预测时的找矿有利度和空间相关性分析   总被引：25，自引：0，他引：25       下载免费PDF全文

池顺都  吴新林 《地球科学》1998,23(1):18

以云南元江地区铜矿ＧＩＳ预测为例,介绍了线型异常和面型异常的找矿有利度分析方法,并给出断裂、物化探异常和地层找矿有利度分析的结果．给出了计算空间相关性的公式,并研究了不同元素化探异常的空间相关性．研究了相关元素的组合异常,论证了在矿产资源预测中应用组合异常的必要性．  相似文献   

矿床统计预测单元划分的方法与程序   总被引：5，自引：0，他引：5  

李新中  赵鹏大  肖克炎  胡光道 《矿床地质》1998,17(4):369-375

在矿床统计预测中,如何确定最佳的统计预测单元,目前尚无通用的准则和算法,它的划分往往取决于地质学家对研究区控矿条件的认识,矿化的实际分布殂态及统计预测所采用的评价模型等多种因素。系统功能齐全,基本上满足了资源评价的各种需求,实现了预测单元划分的自动化和智能化。  相似文献   

Accounting for Estimation Optimality Criteria in Simulated Annealing   总被引：1，自引：0，他引：1  

P. Goovaerts 《Mathematical Geology》1998,30(5):511-534

This paper presents both estimation and simulation as optimization problems that differ in the optimization criteria, minimization of a local expected loss for estimation and reproduction of global statistics (semivariogram, histogram) for simulation. An intermediate approach is proposed whereby an initial random image is gradually modified using simulated annealing so as to better match both local and global constraints. The relative weights of the different constraints in the objective function allow the user to strike a balance between smoothness of the estimated map and reproduction of spatial variability by simulated maps. The procedure is illustrated using a synthetic dataset. The proposed approach is shown to enhance the influence of observations on neighboring simulated values, hence the final realizations appear to be better conditioned to the sample information. It also produces maps that are more accurate (smaller prediction error) than stochastic simulation ignoring local constraints, but not as accurate as E-type estimation. Flow simulation results show that accounting for local constraints yields, on average, smaller errors in production forecast than a smooth estimated map or a simulated map that reproduces only the histogram and semivariogram. The approach thus reduces the risk associated with the use of a single realization for forecasting and planning.  相似文献   

Seismic quiescence before the M 7, 1988, Spitak earthquake, Armenia   总被引：7，自引：0，他引：7  

Max Wyss  & Artak H. Martirosyan 《Geophysical Journal International》1998,134(2):329-340

A detailed analysis of the 35  yr of seismicity between 1962 and 1997 using a gridding technique shows that the M 7, Spitak earthquake of 1988 December 7 was preceded by a quiescence anomaly that started at approximately 1984±0.5, and lasted about 5±0.5  yr, up to the main shock. This quiescence anomaly had a radius of about 20±3  km, estimated from circular areas with 75 per cent rate decrease, centred at the point of maximum significance of the anomaly. The quiescence was clearly present in the aftershock volume during the 5  yr before the 1988 main shock, but its statistically strongest expression was located 30  km NW of the epicentre. This anomaly fulfills the association rules between precursory quiescence anomalies and main shocks, even for a tight definition, and is therefore proposed as a case of precursory quiescence. The largest value of the standard deviate Z , found by random selection of samples by gridding, was Z =14 for a time window of T _w=3  yr, using a sample size of N =300 events. This makes this anomaly the strongest observed so far, and it is the first documented in an environment of continental collision. There are no false alarms exceeding in significance the precursor. The Armenian earthquake catalogue used for this study had 4600 earthquakes with M ≥ M _min=2.2 in the area bounded by 39.5° to 42°N/42.5° to 47°E. From the point of view of homogeneous reporting this is the best catalogue we have analysed so far. The limits of the data used and the density of the grid are dictated by the data, and have no influence on the results. The choice of free parameters does not influence the results significantly within the following limits: 100≤ N ≤500, 2≤ T _w≤7, 2.2≤ M _min≤2.8.  相似文献   

Earthquake recurrence-time variations with and without fault-zone interactions   总被引：1，自引：0，他引：1  

Thorsten W. Becker  & Harro Schmeling 《Geophysical Journal International》1998,135(1):165-176

  相似文献   

滇西地区小地震群特征     

龙晓帆  王绍晋  陈立德  张喜玲  陈燕  罗淑进 《华北地震科学》1998,16(1):30-35

根据滇西地区（23°．8－28°N;97°．0－101°．5E）1966年1月－1996年7月89个ML≤4．7的小地震震群资料分别总结出滇西地区H,K,U,η,b,△M参数的判别指标和地区特征。着重讨论了小地震震群与云南及邻区中强震关系,以及综合利用上述参数尝试预报未来中强震。  相似文献   

包头西6.4级地震前地球物理场特征的研究     

马锦琳  马桂芳 《华北地震科学》1998,16(1):61-67

通过对包头６．４级地震前较大范围前兆资料的研究,认为一个强烈地震在发生之前,围绕震中区不同区域内,将出现具有不同特点的前兆场异常群。其近场（Δ≤１００ｋｍ）的主要特征是具有较长时间尺度的趋势性异常;中场（１００ｋｍ〈Δ≤２００ｋｍ）的主要特征是趋势和突发性异常并重;而远场（Δ〉２００ｋｍ）则一般无趋势性异常,只有急剧变化的短临异常。  相似文献   

川青藏地区的地震活动及震源特征   总被引：4，自引：0，他引：4       下载免费PDF全文

高原  马林 《地震地质》1998,20(4):126-422

在分析区域地震活动和构造环境及利用ＧＤＳＮ的宽频带波形资料分析震源破裂特征的基础上,结合余震资料,讨论了１９８８～１９９０年发生在四川和青海的９次强震的震源破裂和余震分布特征,分析了四川、青海、西藏相邻区域内的地震能量迁移,并用单键群分析方法对１９７０年以来的地震活动总体图象进行了研究。结果表明,这些地震的震源性质与构造应力环境相符,但青海地震的震源都具有较大的逆掩分量,与过去的走滑震源性质不同,而四川地震的震源Ｐ轴不接近水平方向与当地的“Ｙ”字形复杂构造有关  相似文献   

Chemical ozone loss in the Arctic vortex in the winter 1995–96: HALOE measurements in conjunction with other observations     

R. Müller  J.-U. Grooß  D. S. McKenna  P. J. Crutzen  C. Brühl  J. M. Russell III  L. L. Gordley  J. P. Burrows  A. F. Tuck 《Annales Geophysicae》1998,17(1):101-114

Severe chemical ozone loss has been detected in the Arctic in the winter and spring of 1995–96 by a variety of methods. Extreme reductions in column ozone due to halogen catalysed chemistry were derived from measurements of the Halogen Occultation Experiment (HALOE) on board the Upper Atmosphere Research Satellite in the Arctic vortex. Here, we discuss further aspects of the HALOE observations in the Arctic over this period. Potential problems, both in the data themselves and in the methodology of the data analysis are considered and the reason for the differences between the Arctic ozone losses deduced from HALOE data version 17 and 18 is analysed. Moreover, it is shown that HALOE measurements in the Arctic in winter and spring 1995–96 compare well with observations by other ground-based and satellite instruments.  相似文献   

Prediction of the Earlier Strong Aftershocks in the Earthquake Sequences by the Pseudo-Periodicity Method     

Wang Chunzhen  Huang Hanming  and Wang BiquanInstitute of Geophysics  CSB  Beijing  China 《中国地震研究》1998,(3)

We propose the pseudo-periodicity method and its quantitative prediction indexes for the occurrence time of earlier strong aftershock. We conducted tests of regressive prediction, and the R-value of the tests is 0.45, indicating that this method is effective for prediction.  相似文献