粤东汕头近岸海域灾害地质风险综合评价

Comprehensive assessment of disaster geological risk in Shantou coastal waters in eastern Guangdong

  • 摘要: 基于粤东汕头近岸海域地质和地球物理资料,通过对物探数据进行解译,查明了该区域内主要有活动断层、埋藏古河道、浅层气、不规则浅埋基岩等灾害地质类型,并结合层次分析法和模糊数学法建立了以断层、埋藏古河道、浅层气、浅埋基岩为评价指标的风险评价体系,得出海域内的不同区块的风险性等级,共分低、较低、中、较高、高5个等级。研究区超过70%的区域灾害风险不高,高风险区分布在榕江外河口、海门湾南部,主要受埋藏古河道和断层影响。较高—高风险区工程地质条件较差,存在的不良地质条件可能会给海上工程建设带来风险,选址时应尽量避开此类区域。评价结果与已查明的灾害分布特点吻合,对以后海上工程项目施工有一定的参考价值。

     

    Abstract: The geological and geophysical data in the coastal area of Shantou, eastern Guangdong were interpreted and analyzed for geohazard assessment. Results show that there are mainly active faults, buried ancient rivers, shallow gas, and irregular shallow bedrock in this area. The geohazard was quantitatively assessed by using the analytic hierarchy process and fuzzy mathematics method. A risk assessment system was built, in which faults, buried ancient rivers, shallow gas, and shallow bedrock were used as assessment indicators, and different weights of them were assigned. According to the principle of maximum membership degree, risk levels of different blocks of the study area were calculated from which five risk levels were divided: very low, low, medium, high, and very high. More than 70% of the study area was in low risk, and the high-risk area was distributed in the Rongjiang River outer estuary and the southern part of Haimen Bay, affected mainly by buried ancient rivers and faults. The engineering geological conditions in the high, and very-high risk areas are poor due to unstable geological setting that should be avoided for site selection. The assessment results are consistent with known distribution of geohazards in the coastal waters of Shantou, indicating that the assessment method is reasonable and feasible, and shall have reference values for future development and disaster prevention in sea areas.

     

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