Geology of Christchurch, New Zealand
Geology of Christchurch, New Zealand
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新西兰基督城地质
DOI：
10.2113/gseegeosci.i.4.427
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发表时间：
1995
影响因子：
0.9
通讯作者：
J. Weeber
中科院分区：
文献类型：
--
作者：
L. Brown;R. Beetham;B. R. Paterson;J. Weeber
基督城位于南太平洋新西兰南岛的东海岸。这座城市位于坎特伯雷平原的海岸，毗邻形成班克斯半岛的死火山群。基督城的遗址主要是沼泽，在海滩沙丘沙子后面，以及河口和泻湖，现在已经排干。两条河流--雅芳河和希思科特河--发源于基督城西部的泉水，蜿蜒穿过城市，形成了主要的排水系统。基督城已经发展成为一个服务中心，主要是为了满足坎特伯雷平原肥沃土壤上农业、园艺、果园和市场园艺的需求。北方坎特伯雷平原下的冲积含水层中的地下水为生活、工业、牲畜和灌溉需求提供了充足的优质水供应。从基督城的内陆平原上挖掘的坑中，可以获得来自南阿尔卑斯山脉（南岛的中轴山脉）侵蚀的大量杂砂岩砾石和沙子。在基督城附近的班克斯半岛的港口山斜坡上可以找到粘土和火山岩。一条2.6公里长的铁路隧道和邻近的公路隧道穿过港口山的火山岩，将基督城与利特尔顿港的利特尔顿港连接起来。基督城面临的地质制约因素包括洪水、可变地基条件、港口山斜坡不稳定性和海岸侵蚀。怀马卡里里河及其在南阿尔卑斯山的集水区在1850年城市建立后不久就开始修建截流堤和河流重新调整之前经常淹没基督城。由于高水位和河流漫滩、沼泽和河口泻湖环境的横向变化，基础条件变化，对建筑设计和施工施加了限制。易受边坡失稳的影响是在黄土和崩积层上进行城市开发的一个问题，这些黄土和崩积层覆盖着港口山的火山岩。稳定的地基条件是通过在现场和实验室中识别潜在的活跃侵蚀过程以及使用适当的设计和施工实践来确定的。还必须考虑海岸侵蚀过程以及海洋和河流对预计的全球变暖的反应。基督城地区的地质、构造背景和地震活动表明，未来将发生对该市产生重大影响的大地震。预计地震会产生液化、滑坡、地面开裂和海啸。为减轻这些现象的后果而进行规划和设计是备灾的基本先决条件。环境、水文地质和地质因素的影响正在纳入城市规划。随着地质知识和数据库的扩大，今后应继续查明和量化地质灾害，并执行旨在阻止不负责任地使用土地的条例和规划。
Christchurch is situated on the east coast of the South Island of New Zealand in the south Pacific Ocean. The city is located at the coast of the Canterbury Plains adjacent to an extinct volcanic complex forming Banks Peninsula. The site of Christchurch was mainly swamp, behind beach dune sand, and estuaries and lagoons, which have now been drained. Two rivers—the Avon and Heathcote—which originate from springs in western Christchurch, meander through the city and form the main drainage system. Christchurch has developed as a service center, principally in response to the requirements of agriculture, horticulture, orcharding and market gardening on the fertile soil of the Canterbury Plains. Ground water in alluvial aquifers underlying the northern Canterbury Plains provides a plentiful supply of excellent quality water for domestic, industrial, live stock and irrigation requirements. An abundant supply of greywacke gravel and sand derived from erosion of the Southern Alps—the axial mountain range of the South Island—is available from pits excavated on the plains inland from Christchurch. Clay and volcanic rock are available near Christchurch from the Port Hills slopes of Banks Peninsula. A 2.6 km long rail tunnel and an adjacent road tunnel pass through the volcanic rock of the Port Hills, linking Christchurch with the port of Lyttelton in Lyttelton Harbor. Geological constraints of concern to Christchurch include flooding, variable foundation conditions, slope instability on the Port Hills, and coastal erosion. The Waimakariri River with its catchment in the Southern Alps, regularly flooded Christchurch prior to stopbank construction and river realignment, which began shortly after the city was established in 1850. Variable foundation conditions as a consequence of a high water table and lateral changes from river floodplain, swamp, and estuarine-lagoonal environments, impose constraints on building design and construction. Susceptibility to slope failure instability is a problem for urban development on the loessial soils and colluvium which mantles the volcanic rock of the Port Hills. Stable foundation conditions are determined by the identification of potentially active erosion processes in the field and in the laboratory, and the use of appropriate design and construction practices. Coastal erosion processes, and sea and river response to a predicted global warming, must also be considered. The geology, tectonic setting, and active seismi-city of the Christchurch area indicate that future large earthquakes will occur which will have major impact on the city. Earthquakes are expected to produce liquefaction, landsliding, ground cracking, and tsunami. Planning and design to mitigate the consequences of these phenomena are an essential prerequisite for preparedness. The effects of environmental, hydrogeological, and geological factors are being incorporated in urban planning. The identification and quantifying of geological hazards, and the implementation of regulation and planning designed to discourage irresponsible land use, should continue in the future as the geological knowledge and database is expanded.