Geological and morphological study of the Jiufengershan landslide triggered by the Chi-Chi Taiwan earthquake

The Jiufengershan rock and soil avalanche is one of the largest landslides triggered by the Chi-Chi earthquake Taiwan 1999. The landslide destabilized the western limb of the Taanshan syncline along a weak stratigraphic layer. It involved a flatiron remnant, which was almost entirely mobilized during the earthquake. The avalanche was slowed down by NS trending ridges located downstream along the Jiutsaihu creek. The landslide affected a 60 m thick and 1.5 km long sedimentary pile composed of shales and sandstones, which dip 22°SE toward a transverse valley. The triggering mechanism and the sliding process were analyzed by means of geological and morphological data from aerial photographs and observed in the field. A high-resolution airborne Light Detection and Ranging (LiDAR) image taken 2.5 years after the landslide allows the identification of morphological structures along the sliding surface and the landslide accumulation. The sliding surface shows several deformation structures such as fault scarps and folds. These structures are interpreted in terms of basal shear stresses created during the avalanche. Three major joint sets were identified at the sliding surface. The isopach map of the landslide was calculated from the comparison between elevation models before and after the earthquake. The coseismic volume of mobilized material and landslide deposit data are 42 × 10⁶ m³ and 50 × 10⁶ m³, respectively. The geometry of the landslide accumulation in the field has an irregular star shape. The morphology of the deposit area shows a sequence of smooth reliefs and depressions that contrast with the neighboring ridges.     

Regional bias of landslide data in generating susceptibility maps using logistic regression: Case of Hong Kong Island

On the basis of 1,834 landslide data for Hong Kong Island (HKI), landslide susceptibility maps were generated using logistic regression and GIS. Regional bias of the landslide inventory is examined by dividing the whole HKI into a southern and a northern region, separated by an east-west trending water divide. It was found that the susceptibility map of southern HKI generated by using the southern data differs significantly from that generated by using northern data, and similar conclusion can be drawn for the northern HKI. Therefore, a susceptibility map of HKI was established based on regional data analysis, and it was found to reflect closely the spatial distributions of historical landslides. Elevation appears to be the most dominant factor in controlling landslide occurrence, and this probably reflects that human developments are concentrated at certain elevations on the island. Classification plot, goodness of fit, and occurrence ratio were used to examine the reliability of the proposed susceptibility map. The size of landslide susceptible zones varies depending on the data sets used, thus this demonstrates that the historical landslide data may be biased and affected by human activities and geological settings on a regional basis. Therefore, indiscriminate use of regional-biased data should be avoided.     

Hydrogeochemical Anomalies in the Springs of the Chiayi Area in West-central Taiwan as Possible Precursors to Earthquakes

Water samples from both hot and artesian springs in Kuantzeling in west-central Taiwan have been collected on a regular basis from July 15, 1999 to the end of August 2001 to measure cation and anion concentrations as a tool to detect major earthquake precursors. The data identify chloride and sulfate ion anomalies few days prior to major quakes and lasting a few days afterward. These anomalies are characterized by increases in Cl^- concentrations from 34.9% to 41.2% and 71.5% to 138.1% as well as increases in SO₄^2- concentrations from 232.7% to 276.8% and 100.0% to 155.1% above the means in both hot and artesian springs. The occurrence of these anomalies is probably explained first as stress/strain-induced pressure changes in the subsurface water systems which then generate precursory limited geochemical discharges at the levels of subsurface reservoirs. Therefore, finally leading to the mixing of previously separated subsurface water bodies occurs. This suggests that the hot and artesian springs in the Kuantzeling area are possible ideal sites for recording strain changes serving well as earthquake precursors.     

勘察设计招投标中存在的问题分析及建议

本文分析了现行的勘察设计招投标中存在的亟待解决的问题，并提出了相应的对策和建议。     

基于AHP的勘察设计市场管理决策分析

为建立公开、公正、公平、竞争有序、统一开放的勘察设计市场秩序,基于AHP,分析了勘察设计市场存在的主要问题及其对市场的影响程度;根据计算结果,提出了规范勘察设计市场的主要对策及其实施的轻重缓急.     

Cross-border regional development in Southern China

Cross-border zones have been developed rapidly in China since 1979. This was largely due to the global economic restructuring in the post-Fordist era. The enclave of Hong Kong plays an indispensable role in the process. While China adopts the Open Door Policy, factories in Hong Kong are quick to relocate to the Pearl River Delta region in order to benefit from the low production costs and other preferential policies. The paper first reviews the factors leading to the economic integration between Hong Kong and the Pearl River Delta region of southern China. It then examines the sectoral changes and the socio-economic data of the region. Rapid urbanization and rural urbanization are reflected in the quest for infrastructural development plans and the loss of quality farmland. They also bring along environmental hazards. The paper concludes with the call for a comprehensive development strategy for the region into the next century. This revised version was published online in August 2006 with corrections to the Cover Date.     

油气化探中△C与烃类异常的相互配置关系

通过对△Ｃ（即后生碳酸盐）成因机理的分析，结合典型实例，对△Ｃ异常与烃类异常的相互配置关系及其与地下深处油气藏联系的研究，大量事实证明，△Ｃ异常并不总是与烃类异常一致的，只有当△Ｃ异常与烃类异常较一致时，△Ｃ异常才具有找油气藏的意义。     

三山岛金矿海边地下开采矿山稳定性的数值模拟分析

本文用数值模拟的分析方法, 评价了三山岛金矿地下开采引起的开采效应及地表下沉盆地的变形特征。结果表明, 矿山地表是稳定的, 上部一期工程开采引起的地表最大下沉量不超过700mm, 深部开挖时不超过995mm左右；在采场充填的情况下, 地表下沉值将降低55%左右；由于矿山地表变形较小, 加之覆盖层第四纪中存在着两层总厚度8～12m的隔水粘水层, 因此不致沟通地表水与井下的直接联系而危及矿山的安全。     

中国大陆与香港及周围地区的地震目录完全性分析

地震活动性中心Ｇｕｔｅｎｂｅｒｇ－Ｒｉｃｈｔｅｒ关系（ｌｏｇＮ＝ａ－ｂＭ）在确定地震发生率时起着重要作用，实际分析中存在的对Ｇ－Ｒ关系的偏离主要是由于地震目录的不完全性引起：即在低震级端因地震的监测能力有限，在高震级端因大震的稀少导致的统计涨落。