关于地形测图中视距平距的严密计算问题

推导了严密的视距平距计算公式,据此对两个近似公式的近似性及对大比例尺地形测图的影响进行了分析,所得结论有助于视距公式在实际工作中的应用。     

经纬仪互瞄法在短边方位传递中的应用

讨论了短边测角的主要误差来源和影响,提出了短边方位传递的测量方法。最后通过一个实例,说明互瞄法方位传递可以达到很高的精度。     

开采沉陷中的抽样定理及其应用

根据数字处理中的数学原理，提出了开采沉陷中的抽样定理。以此为基础，导出了地表移动观测站的合理点间距ｒ·其值为Ｈ（５ｔ），获得了以离散的地表移动观测值或预计值，恢复其连续性的地表移动变形值的计算公式。并以计算实例，给出了其计算方法。     

Criteria to Compare Estimation Methods of Regionalized Compositions

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.     

超远距离HF传播预测值与实测值的比较

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。     

Groundwater monitoring for earthquake prediction by an amateur network in Japan

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.     

昌马断裂带地震滑坡的展布特征

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。     

Seasonal changes in surface level of a salt marsh creek

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.     

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

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。