SBAS时序分析技术监测现代黄河三角洲地面沉降

Monitoring Ground Subsidence in the Modern Yellow River Delta Based on SBAS Time-series Analysis

  • 摘要: 本文将SBAS (small baseline subset)时序分析技术应用于现代黄河三角洲地面沉降监测。选取覆盖研究区的39景ERS1/2 SAR数据,提取了1992至2000年现代黄河三角洲地面沉降速率,结果与水准观测数据基本保持一致,研究发现胜利油田中心开采区最大地面沉降速率可达-33.2 mm/a。研究表明,黄河三角洲地面沉降主要由石油开采(采油和抽取浅层地下水用于回注)、地下水抽取、地表载荷增加、沉积物固结压实引发,沉积物固结压实和石油开采对现代黄河三角洲地面沉降的贡献显著。

     

    Abstract: Land subsidence in the modern Yellow River Delta at high spatial and temporal resolution was deduced from SBAS time-series analysis of ERS1/2 data. The experimental results show that land subsidence in the modern Yellow River Delta is widespread and unevenly distributed with large differences. The average subsidence rate is -5.1 mm/yr, while the highest subsidence rate of -33.2 mm/yr occurring in the subsidence funnel formed by an oil field. The InSAR results are shown to be reliable, when compared with leveling survey measurements. Ground based leveling measurements included 53 leveling points were used to evaluate the accuracy of our SBAS time-series analysis results with a consistent deformation trend between the two sets of results. A comparison between leveling points and their nearest SBAS points at the same time interval showed they were in complete agreement, while the mean square error between them was at the mm level. The main influencing factors differ by region. Severe land subsidence however, is caused by oil extraction including extracting nearby shallow groundwater used for artificial water injection after oil exploitation and sediment consolidation. Oil exploitation was the main influencing factor and responsible for the rapid, patchy subsidence evident at Dongying city, Hekou district, Gudao town, Zhuangxi, and the Gudong oilfield. Groundwater extraction for making salt and oilfield water injection is likely responsible for land subsidence in the Liuhu township and at the Guangrao salt pan. Increased surface load aggravated land subsidence in the old urban district of Dongying city, and sediment consolidation might be considerable after the lobe is abandoned.

     

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