ON BIO-EFFECTS ON KARST LANDSCAPE IN JIUZHAIGOU CONSERVATION, SICHUAN PROVINCE, CHINA—WITH SPECIAL REFERENCE TO A MICROMORPHOLOFICAL APPROACH

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APPROACH TO KARST SOLUTION PROCESS RESPONSES ON CLIMATE

ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｌｕｔｉｏｎａｓａｋａｒｓｔｇｅｏｍｏｒｐｈｏｌｏｇｉｃａｌｐｒｏｃｅｓｓｉｎｌａｎｄｆｏｒｍｄｅｖｅｌｏｐｍｅｎｔｈａｓｌｏｎｇｂｅｅｎｒｅｃｏｇｎｉｚｅｄ.Ｓｉｎｃｅｔｈｅｋａｒｓｔｐｒｏｃｅｓｓｅｓａｒｅａｌｍｏｓｔｅｎｔｉｒｅｌｙｓｏｌｕｔｉｏｎ,ｔｈｏｕｇｈｋａｒｓｔｌａｎｄｆｏｒｍｓａｒｅｎｏｔｏｎｌｙｃａｕｓｅｄｂｙｓｏｌｕｔｉｏｎｂｕｔａｌｓｏｂｙｅｒｏｓｉｏｎ,ｔｈｅｃｉｒｃｕｌａｔｉｏｎａｎｄｃｈｅｍｉｃａｌｃｏｍｐｏｓｉｔｉｏｎｓｏｆｋａｒｓｔｕｎ…     

Yucatán karst features and the size of Chicxulub crater

The buried Chicxulub impact structure is marked by a dramatic ring of sinkholes (called cenotes if containing water), and adjacent less prominent partial rings, which have been shown to coincide with maxima in horizontal gravity gradients and a topographic depression. These observations, along with the discreteness and spacing of the features, suggest a formation mechanism involving faulting in the outer slump zone of the crater, which would thus have a diameter of approximately 180 km.
An opposing view, based primarily on the interpretation of gravity data, is that (he crater is much larger than the cenote ring implies. Given the association of the known cenote ring with faults, we here examine northern Yucatan for similar rings in gravity, surface features and elevation, which we might expect to be associated with outer concentric faults in the case of a larger, possibly multiring, structure.
No such outer rings have been found, although definite patterns are seen in the distribution of karst features outside the crater rim. We explain these patterns as resulting mainly from deformation related to the block fault zone that parallels tbe shelf edge of eastern Yucatan.     

碳酸盐岩地区电磁波场的特性分析

形成岩溶的高阻碳酸盐岩对电磁波的吸收较弱，而且成层沉积的特定环境使碳酸盐岩地区岩石的各向异性现象较明显，由于地空界面的存在及岩溶洞壁两侧介质电性差异明显，界面清晰，又使电磁波出现强烈的反射及散射现象，从理论上对碳酸盐岩地区电磁波传播的特有现象进行了研究和分析，并给出结论。     

二维TIM中的传播矩阵与面波相速度

本文利用横向各向同性介质（ＴＩＭ）中的传播矩阵和面波形成条件，导出了面波波慢度方程。对瑞利波给出了各向同性及横向各向同性弹性介质中其相速度的解析解；对于勒夫波，给出了横向各向同性介质中的波慢度方程。     

Environmental and legal aspects of karst areas

 Environmental impacts on karst settings are common as they are more sensitive than those of other rock terrains. Regulatory procedures that are effective in other rock terrains are not necessarily applicable to karst settings. Development and exploitation by man that affect the karst hydrology regime can trigger catastrophic events and result in numerous legal actions where the effects of changes go beyond property boundaries. A great variety of regulations and examples of litigation exist for karst areas. Received: 25 October 1994 · Accepted: 17 October 1995     

岩溶地下水集中开采区水质系统预测研究

在岩溶地区，地下水的超强度开采与工业“三废”及生活废弃物不合理的排放，造成了地下水较严重的污染。用动态系统方法建立的地下水污染时间序列递推预测模型，在岩溶地下水环境质量预测与管理方面都具有指导意义。     

Causes of Land Subsidence in the Kingdom of Saudi Arabia

The occurrence of land subsidence in the Kingdom Saudi Arabia is either natural or man-made. Natural land subsidence occurs due to the development of subterranean voids by a solution of host rocks in carbonate and evaporite terrains, over many areas of Saudi Arabia. Man-induced land subsidence is either due to the removal of groundwater in the agricultural areas or to wetting of unstable soils. Therefore, earth fissures and a lowering of the ground surface in unconsolidated sediments took place in alluvial plains and volcanic vent terrains. Unstable soils include Sabkha soils and loess sediments. These types of soils occur in coastal plains, desert areas and volcanic terrains. When this soil is wetted either during agricultural activities, waste disposal or even during a rain storm, subsidence takes place due to either the removal of salts from the Sabkha soil or the rearrangement of soil particles in loess sediments.     

Karst Hazard Assessment of Eastern Saudi Arabia

Karst phenomena exist in areas in the eastern part of Saudi Arabia, forming solution features such as sinkholes, collapsed dolines and solution caverns, as a result of the chemical leaching of the carbonate and evaporite formations by percolating water. The instability of these karst phenomena could produce land subsidence problems. This paper reviews the geology of documented karstic rock units in Saudi Arabia and proposes a simple engineering classification of the solution features characteristic of limestone. Two case histories in the Dhahran area, eastern Saudi Arabia, will be used as examples for the application of a modified engineering classification.