基于微地貌特征的西太平洋菲律宾海海底稳定性评价

Submarine stability evaluation of the Philippine Sea of the Western Pacific based on microgeomorphologic features

  • 摘要: 随着海洋战略地位的逐步提高,深远海海底资源开发和海洋工程建设将面临巨大挑战,主要是受限于技术手段,高精度调查资料难以获取,无法全面准确地进行海底稳定性评价。针对这一问题,本文提出了基于微地貌特征的深远海海底稳定性评价方法。基于已有的研究工作,本文选取西太平洋菲律宾海中南部某区域为研究区,利用ArcGIS平台建立研究区DEM(Digital Elevation Model),提取宏、微观地貌因子,结合全球地震数据、研究区底质类型和潜在地质灾害分布特征,运用模糊数学方法评价研究区海底稳定性,并绘制海底稳定性区划图。结果显示,对区域3220个评价单元进行稳定性分析,可将研究区海底稳定性划分为5个等级,包括基本稳定、较稳定、中等稳定、较不稳定和不稳定。其中,稳定区主要集中在较为平坦的中北部,不稳定区多发育在九州-帕劳海岭、海山、山间盆地等大规模地貌单元发育区,分析揭示,研究区海底稳定性与微地貌特征密切相关。因此,本文提出的基于微地貌特征的海底稳定性评价方法,能够很好地服务于深远海海底稳定性评价。

     

    Abstract: In addition to underwater resource development, submarine construction and engineering have become great concerns to marine geoscientists. Both of them require accurate sea-bottom stability evaluation. However, mainly due to the limitation of offshore technology, it is difficult for the time being to acquire high-precision data for accurate and comprehensive evaluation of the stability. In order to solve this problem, a method for stability evaluation of submarine engineering is proposed in this paper based on microgeomorphologic features. Based on the existing research, this paper selected a region in the south-central Philippines Sea of the Western Pacific as the target area, and a Digital Elevation Model (DEM) using ArcGIS is established to extract macro and micro geomorphological factors. Combined with seismic data, bottom sediments and distribution pattern of geo-hazards in the study area, the fuzzy mathematical evaluation method was adopted to evaluate the submarine stability, and an evaluation map was compiled. The results show that by analysis of the stability for 3220 evaluation units in the region, the seabed can be divided into 5 grades according to its stability, including stable, basic stable, relatively stable, relatively unstable and unstable. The stable areas are mainly located in the central and northern part where the sea bottom is flat, while the unstable areas occur in the large-scale geomorphic units such as the Kyushu-Palau Ridge, seamounts and intermontane basins. It is revealed that the stability of the seabed of the study area is closely related to the change in topography and landform. The practice proves that the submarine stability evaluation method based on micro-geomorphic features proposed in this paper is useful and efficient, and may well serve the stability evaluation required in similar regions.

     

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