Criteria to Compare Estimation Methods of Regionalized Compositions   总被引：1，自引：0，他引：1  

J. A. Martín-Fernández  R. A. Olea-Meneses  V. Pawlowsky-Glahn 《Mathematical Geology》2001,33(8):889-909

The additive logratio (alr) transformation has been used in several case studies to predict regionalized compositions using standard geostatistical estimation methods such as ordinary kriging and ordinary cokriging. It is a simple method that allows application to transformed data all the body of knowledge available for geostatistical analysis of coregionalizations without a constant sum constraint. To compare the performance of methods, it is customary to use a univariate crossvalidation approach based on the leaving-one-out technique to evaluate the performance for each attribute separately. For multivariate observations this approach is difficult to interpret in terms of overall performance. Therefore, we propose using appropriate distances in real space and in the simplex, to improve the crossvalidation approach and, going a step forward, to adapt the concept of stress from multidimensional scaling to obtain a global measure of performance for each method. The Lyons West oil field of Kansas is used to illustrate the impactof using different distances in the performance of ordinary kriging versus ordinary cokriging.  相似文献   

超远距离HF传播预测值与实测值的比较          下载免费PDF全文

杜军虎  孙宪儒  王聚杰 《极地研究》1993,5(3):55-59

本文主要对超远距离HF传播信号场强测量值与山CCIR第894—2号报告书方法所做的预测值进行了比较,其平均偏差为-1.7dB,标准均方根偏差为13.5dB。最后分析了偏差的原因并对预测方法进行了评估,指出预测值偏低和对极点聚焦公式应当修改,这将大大提高第894—2号报告方法的预测精度。  相似文献   

煤田地震勘探中应用偏移剖面作构造图问题初探     

张立柱  耿玉岭 《物探与化探》1993,17(4):258-265

本文针对煤田地震勘探的特点,就如何应用偏移时间剖面直接作构造图问题进行了论述,提出了一套完整的交点闭合方法和空间校正方法。并结合实际使用PC-1500微机进行空间校正作构造图,实践证明效果良好。  相似文献   

Groundwater monitoring for earthquake prediction by an amateur network in Japan   总被引：1，自引：0，他引：1  

Yasue Oki  Shiro Hiraga 《Pure and Applied Geophysics》1988,126(2-4):211-240

Since 1976 groundwater-levels and the temperature of thermal water have been monitored in 100 wells distributed mostly in the southern Kanto and Tokai districts of Japan in order to predict earthquakes. Good examples of groundwater precursors were recognized prior to the following destructive earthquakes: the 1978 West Off Izu-Oshima Earthquake (M 7.0), the 1978 Off Miyagi Earthquakes (M 7.4), and the 1980 East Off Izu Peninsula Earthquake (M 6.7). In the 1978 West Off Izu-Oshima Earthquake, groundwater levels and the Japan Meteorological Agency (JMA) volume strainmeters, installed in the Izu peninsula, showed precursory changes at about the same time. In the other cases, however, precursory behavior was observed only in water level and temperature monitoring. Empirical relations are given between earthquake magnitude and the epicentral distance of the farthest groundwater anomaly, and between earthquake magnitude and the precursor time of groundwater.  相似文献   

浅谈后方交会     

田养权 《华东地质学院学报》1989,12(4):58-70

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昌马断裂带地震滑坡的展布特征     

康来迅  王建荣 《山地学报》1995,(1)

根据大量的野外地质调查和测量资料分析，讨论了地震滑坡沿昌马断裂带走向和倾向的展布特征。研究认为昌马断裂带地震滑坡主要发生在山坡坡度３０°－５０°的部位和山坡地形高差１００－３００ｍ的部位；地震滑坡规模、数量的分布特征与断裂活动强度的分布变化有密切的关系，这是地震滑坡与降水滑坡、人为滑坡和融冻滑坡的最大区别；最后讨论了地震滑坡最大水平滑距的规律，对地震滑坡灾害预测有很现实的意义。  相似文献   

Seasonal changes in surface level of a salt marsh creek     

Alan P. Carr  Michael W. L. Blackley 《地球表面变化过程与地形》1986,11(4):427-439

Nineteen surveys were carried out over a two-year period to determine the surface height of a salt marsh creek located on the north side of the River Esk, Cumbria, England. An AGA 112 electromagnetic distance measurer mounted on a Wild TI theodolite was used in conjunction with acrylic reflectors to follow the form of the ground. The results showed that there were no significant net trends in surface level, although seasonal variations of the order of 2 cm occurred. Vegetated areas responded in similar fashion to bare surfaces. It is thought that the elevational changes were attributable to the swelling of clay particles during the winter months rather than the effects of erosion and accretion.  相似文献   

水平多层介质上水平电偶源频率电磁测深的阻抗实部等效电阻率   总被引：3，自引：0，他引：3  

汤井田  何继善 《物探与化探》1994,18(2):92-96

本文讨论了水平电偶源频率电磁测深中阻抗实部等效电阻率的具体定义和算法。用该方法计算的等效电阻率是电磁响应的单值函数,并极大地改善了视电阻率随频率变化的关系曲线,能直观地反映出地电断面随深度的客观变化,数值较接近地层真电阻率,且接近速度很快,假极值效应明显压低。数值计算和实际应用表明该方法是灵活、可行的,可很好地消除频率电磁测深中波区视电阻率曲线在非波区的畸变效应。  相似文献   

全站仪精密距离放样的作业准备     

王军德  郭红霞 《四川测绘》2006,29(3):139-142

本文从理论上分析了全站仪距离放样前应设置的各项作业参数,特别是对关系到从高斯平面距离化算为实地平距的坐标格网因子的计算提供了实用公式,对精密工程放样有实际指导意义。  相似文献   

A Moore's cellular automaton model to get probabilistic seismic hazard maps for different magnitude releases: A case study for Greece     

A. Jimnez  A.M. Posadas 《Tectonophysics》2006,423(1-4):35

Cellular automata are simple mathematical idealizations of natural systems and they supply useful models for many investigations in natural science. Examples include sandpile models, forest fire models, and slider block models used in seismology. In the present paper, they have been used for establishing temporal relations between the energy releases of the seismic events that occurred in neighboring parts of the crust. The catalogue is divided into time intervals, and the region is divided into cells which are declared active or inactive by means of a threshold energy release criterion. Thus, a pattern of active and inactive cells which evolves over time is determined. A stochastic cellular automaton is constructed starting with these patterns, in order to simulate their spatio-temporal evolution, by supposing a Moore's neighborhood interaction between the cells. The best model is chosen by maximizing the mutual information between the past and the future states. Finally, a Probabilistic Seismic Hazard Map is given for the different energy releases considered. The method has been applied to the Greece catalogue from 1900 to 1999. The Probabilistic Seismic Hazard Maps for energies corresponding to m = 4 and m = 5 are close to the real seismicity after the data in that area, and they correspond to a background seismicity in the whole area. This background seismicity seems to cover the whole area in periods of around 25–50 years. The optimum cell size is in agreement with other studies; for m > 6 the optimum area increases according to the threshold of clear spatial resolution, and the active cells are not so clustered. The results are coherent with other hazard studies in the zone and with the seismicity recorded after the data set, as well as provide an interaction model which points out the large scale nature of the earthquake occurrence.  相似文献