摘要:
汶川地震后,余震活动频繁,加之成都平原内城市发展迅速,容易诱发地面沉降;对成都平原地面沉降进行监测,及时掌握沉降信息,可为相关决策提供科学依据。基于ENVISAT ASAR数据,采用小基线集( small baseline subset,SBAS)-InSAR技术,对成都平原2008―2010年地面沉降进行了监测。结果表明,各主要城市在监测时段内的地表累积形变量在-8~14 mm之间,总体形变量不大;成都平原西部区域受地震影响呈抬升趋势,沉降主要集中于成都市北侧和德阳市以南部分区域,最大沉降量为-22 mm,沉降范围随时间推移呈扩大趋势。通过实测数据验证了监测结果,精度达到2.9 mm。成都平原不存在区域性沉降的构造背景,且地下水资源丰富,沉降自然诱因不明显,城市建设活动可能为沉降的人为诱因。该成果可为今后成都平原主要城市更加精细的地面沉降监测工作提供参考。
Abstract:
After Wenchuan earthquake , the aftershocks happened frequently .Coupled with the rapid development of cities, they are likely to cause ground subsidence .So monitoring the surface of Chengdu Plain and obtaining the deformation information could provide scientific basis for the relevant decisions .In this paper , based on ENVISAT ASAR data, the authors monitored the ground subsidence of Chengdu Plain from 2008 to 2010 using SBAS-InSAR technology .The results show that the average surface deformations were between -8 to 14 mm in major cities in the Chengdu Plain during the monitoring period , the deformation is not prominent , and the western part of the plain showed a uplift trend caused by earthquake .The subsidence area in the north of the Chengdu City and south to the Deyang City was up to -22 mm with the expansion of the subsidence area .The monitoring results were validated by measured data and the accuracy is 2.9 mm .The Chengdu Plain has no regional tectonic setting of subsidence and has abundant groundwater resources , so the natural cause of subsidence is not obvious; the city building activity might be the major cause of subsidence .
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