黄润秋, 李为乐. 2009: 汶川大地震触发地质灾害的断层效应分析. 工程地质学报, 17(1): 19-28.
    引用本文: 黄润秋, 李为乐. 2009: 汶川大地震触发地质灾害的断层效应分析. 工程地质学报, 17(1): 19-28.
    HUANG Runqiu, LI Weile. 2009: FAULT EFFECT ANALYSIS OF GEO-HAZARD TRIGGERED BY WENCHAUN EARTHQUAKE. JOURNAL OF ENGINEERING GEOLOGY, 17(1): 19-28.
    Citation: HUANG Runqiu, LI Weile. 2009: FAULT EFFECT ANALYSIS OF GEO-HAZARD TRIGGERED BY WENCHAUN EARTHQUAKE. JOURNAL OF ENGINEERING GEOLOGY, 17(1): 19-28.

    汶川大地震触发地质灾害的断层效应分析

    FAULT EFFECT ANALYSIS OF GEO-HAZARD TRIGGERED BY WENCHAUN EARTHQUAKE

    • 摘要: 512汶川大地震(Ms=8.0)触发了数以万计的崩滑地质灾害,分布范围约10万km2。这些地质灾害的空间分布固然受地形地貌、地层岩性和人类工程活动等因素的影响,然而主要还是受到发震断层的控制,沿发震断裂呈带状分布。通过都(江堰)汶(川)路、北川安县、马公红光3个地质灾害集中发育区的研究,发现汶川地震地质灾害具有以下断层效应:(1)由于属逆断型发震,地质灾害的分布表现出了明显的上/下盘效应,发震断层上盘较下盘地质灾害分布密度高、范围广、规模大;(2)断层上盘0~7km范围为地质灾害强发育区,断层上盘7~11km范围和下盘0~5km范围为地质灾害中等发育区;绝大多数的大型滑坡都分布在距断层5km范围内;(3)断裂的转折和错列部位是地质灾害集中发育部位,大型地质灾害也往往发生在这些部位;(4)滑坡滑动的优势方向为NW-SE, 与映秀北川断裂的空间展布方向基本垂直,这与地震波垂直于断层方向传播有密切的关系;(5)地震地质灾害主要集中发育在Ⅸ度及其以上烈度的区域。其中,Ⅺ度区发育密度与Ⅹ度区的基本相当,Ⅸ度区灾害密度只有前两者的1/3,而Ⅷ度区发育密度只有Ⅺ度区或Ⅹ度区的1/10。

       

      Abstract: A great number of collapse and slide geo-hazards had been triggered by 512 Wenchuan Earthquake, covering 0.1M km2 or so. Undoubtedly, their distribution was influenced by topography and morphology, stratigraphy, people's engineering operations, and so on. But their distribution mainly was controlled by the faults triggering seism, and they distributed along those faults like a ribbon. Based on the study in three geo-hazards concentration regions, namely, from Dujiangyan to Wenchuan, from Beichuan to Anxian and from Magong to Hongguang, the following fault effects of geo-hazards in Wenchuan Earthquake were found: (1) Because the triggering-earthquake faults were reverse fault, the distribution of geo-hazards showed clear Upper plate/lower plate effect. In detail, compared with lower plate, the upper plate had higher distribution density, wider scope and larger scale; (2) Intensely developed region of geo-hazard ranged from 0 to 7 km in upper plate. Moderately developed region ranged from 7 to 11km in upper plate, and from 0 to 5km in lower plate; Vast majority of lager-scale landslides were about 5km away from faults; (3) The transition and stagger parts of fractures are usually the concentration zone of geo-hazards, and large-scale geo-hazards also frequently happened here; (4) The advantage orientation of sliding was NW-SE, which was nearly orthogonal to the extension direction of the fault of Yingxiu-beichuan. This was closed correlation to the fact that the propagation of earthquake wave was perpendicular to the strike of fault; (5) Earthquake geo-hazards mainly developed in these regions where earthquake intensity was equal to or above IX. The density of development was nearly the same in XI intensity zone and X intensity zone. The geo-hazard density in IX intensity zone was only one-third of the two former zones. Whereas, the development density in VIII intensity zone was only one-tenth of XI intensity zone or X intensity zone.

       

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