A NOTE ON THE USE OF A NOMOGRAM FOR SELF-POTENTIAL ANOMALIES*

A nomogram has been devised for situations, in which the source of a self-potential anomaly can be approximated by an obliquely polarized sphere or horizontal cylinder embedded in a homogeneous half space. The nomogram can be used for rapid determination of three parameters of the target: (1) depth to the centre, (2) angle between the axis of polarization and the horizontal, (3) shift of the point vertically above the centre of the body from zero potential value. The nomogram has been tested and the parameters determined for SP results obtained over ore bodies Weiss and Süleymanköy in the Ergani Copper district, Turkey. The curves computed for the estimated parameters match the field curves well.     

A NOTE ON THE USE OF NOMOGRAMS FOR APPARENT RESISTIVITY COMPUTATION*

Nomograms are presented for the purpose of rapid computation of the apparent resistivity functions from the field data for symmetrical and unsymmetrical linear electrode arrays.     

水位波动信息在含水层中传播特性的实验研究

本文通过一系列水动力学模型实验，探讨了水位波动信息在含水层中传播的特性。实验结果表明，水位波动信息在含水层中传播时发生幅度衰减、时间滞后乃至形态变异等复杂现象，其特征同含水介质的类型、波动信息的频率与传播距离等有关。这样的结果，对地下水位映震条件、映震特征与映震机制的深入研究，提供了有益的启示。     

A CONSTANT DISCHARGE DEVICE FOR AQUIFER TESTS ON LARGE-DIAMETER WELLS

Abstract. The discharge in pumping tests conducted on large-diameter wells declines with the fall of water level. This violates the basic requirement of pumping tests that the discharge should remain constant. A simple device to keep the discharge constant has therefore been developed. This device is also useful in keeping the discharge much lower than the rated capacity of the farmer's pump, and thus in increasing the total test period.
The discharge from the farmer's pump is released in a barrel having a V-notch at the top and an arrangement for returning a part of the discharge to the well. The return flow is gradually reduced through a control valve, and thus the net outflow is kept constant.
This device has been used for conducting pumping tests on several dug wells.     

ON THE USE OF MOVABLE-BED MODELS FOR RIVER PROBLEMS:A STATE-OF-THE-ART

I. INTRODUCTIONMore than a decade ago, under tile auspices of DELFT HYDRAULICS an overview on the use ofmodels for river problems was given (de Vries & van der Zwaard. 1975). Since then a better understanding of morphological processes in rivers has been obtained, their mathematical formulation hasbeen improved and computer facilities have been expended. Scale models and mathematical models arein use. but their field of application is gradually changing. It seems that the better ma…     

利用福建井水位同震变化反演井-含水层体应变及其意义探讨

在对福建地区井水位固体潮M2波海潮负荷改正的基础上,尝试反演汶川MS8.0、日本MW9.0地震对福建地块的井-含水层系统产生的体应变变化。为此收集了汶川、日本大地震时该地区的地下井水位资料,挑选出同震响应明显的井水位资料,计算出各井孔的井水位潮汐因子,从而反演出福建地块井-含水层系统受到的同震体应变变化。结果表明,地震对各井孔所处的含水层造成的体应变基本在10-8量级上,而2次地震对永春井产生的体应变均为10-7量级。     

论地震序列的一种可能的重要成因

本文在Asperity模式和Barrier模式的基础上,提出了另外一种不均匀体模式——障碍体模式,并对该模式进行了数值模拟的研究。结果除证实了我们以前做过的单轴压力下模拟障碍体的实验结果以外,还表明在含有障碍体的断层面上,破裂的扩展与破裂的传播速度、始破裂区域的大小、裂纹的类型以及障碍体所在断层的介质有关。在有围压的情况下,破裂可以先越过或绕过强度较高或尺度较大的障碍体,经一段时间的应力积累过程后,再使障碍体发生破坏。本文通过对震源区中障碍体的性质和影响的研究,解释了海城和邢台两个地震序列形成和发展的可能原因,得到一些较为合理的结果。     

ON THE IMPULSE RESPONSE OF AN AQUIFER

Abstract

The impulse response and the response to a unit step function of the onedirectional semi-infinite aquifer is given, derived from the approximate partial differential equation of the ground water flow. An example is presented.     

NOTE ON THE DETAILED ABLATION STUDIES OF 1959 AND 1962 ON THE GREAT ALETSCH GLACIER

Abstract

Stream channel development in response to the eruption of Mount St. Helens on 18 May 1980, resulted in some of the largest sediment yields documented anywhere on earth. Development of new channels on the 2.7 km³ debris-avalanche deposit in the North Fork Toutle River caused net erosion of as much as 1.3 x 10⁵ t km^?2 annually. Development of these channels followed a four-stage sequence of channel initiation, channel incision with relatively constant width-to-depth ratio, channel widening accompanied by aggradation, and channel widening accompanied by scour-and-fill with little change in average channel elevation. These channels remain unstable both in width and elevation. Lahars affected channel and valley morphology on all flanks of the volcano. Steep, upstream reaches generally incised and widened during the first year following the eruption and aggraded during the following three years. Gently sloping downstream reaches aggraded and widened during the first year and incised during the following three years. The most rapid adjustments occurred during the first two winters following the eruption. The principal effect of the blast on channels throughout the 550 km² devastated area was the subsequent rapid delivery of sand- and silt-size sediment eroded from hillslopes. Channels aggraded during early storms of the 1980–1981 winter but incised during later storms the same winter. Subsequent channel enlargement was constrained by logs deposited in channels by the blast and by post-1980 shallow debris slides. Since 1984, instability and sedimentation in laharand blast-affected channels have been within the range of pre-1980 levels.     

A NOTE ON CONVOLUTION AND PADDING FOR TWO-DIMENSIONAL DATA*

Gupta , V. K., and Ramani , N., 1978, A Note on Convolution and Padding for Two-Dimensional Data, Geophysical Prospecting 26, 214–217. Filtering of gridded data by means of two-dimensional generalized convolution results in a loss of data along the edges of the map. This loss can be counteracted by ‘padding’– filling the surrounding of the input map with some kind of data. Padding by algebraic extrapolation is assumed to be better than surrounding the maps with zeroes. A Føsrtran IV routine for padding by algebraic extrapolation is available from the authors.     

测试水井导水性能的简便试验

这种测试水井含水层导水系数的新方法是利用井口水面空气压力阶变试验,计算出聊城井含水层的导水系数为14.4m2/d,而通过抽水试验得出的导水系数为43.6m2/d,二者有相同的数量级,但新方法比抽水试验简单易行和经济快速,用它来解释地下水微动态更合理,容易推广应用     

关于提高微震事件自动识别效率的一个注记

利用美国国家地震信息中心的地震早期警报系统，通过对数字化地震记录的分析，针对各种可能出现的情况，对微震的自动识别和计算机实时处理进行了讨论。有关结论对地震的自动识别和震源参数的计算测定精度的提高，有重要的参考意义。     

震级-频度关系小震端分布特征的一种可能的解释

通过震级-频度关系资料和地震台站分布资料的分析,发现震级-频度关系曲线在震级较小的一端的分布特征反映了地震能量分形和地震台站状况交互作用的结果,从而在地震序列分析中,考虑不同历史时期地震台站的状况及其影响,是一项必不可少的工作.     

关于逆转方法B解的不唯一性

讀了魏鼎文同志的文章以后,我們想提出以下两点不同的看法,与魏鼎文同志商榷。 1.文献[1]中用两个实例表明,在目前实驗精度內,方法B得不出大气臭氧垂直分布的精細結构,这点对于如何利用方法B的結果是很有参考价值的。不过,我們认为,不能把精細結构方面的某种不定性,看成是方法B解不唯一的証明。