汶川8.0地震地表破裂平通镇段的变形特征
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摘要
2008年5月12日14时28分04秒,四川省汶川县发生MS8.0大地震。发震断裂为龙门山断裂带,地震地表破裂带分布在北川-映秀断裂上的映秀-石坎子段和江油-灌县断裂上的磁峰-睢水段。平武县平通镇地表破裂现象典型,在T1和T2阶地上形成了地震断坎和裂缝。应用高精度GPSRTK技术对平通镇地震断坎及两侧作详细的地形测量,并测量了线性显著的路面中线和鱼塘西边壁。在室内生成高分辨率DEM与大比例尺地形剖面图,量取同震垂直与水平位移,并估算压缩缩短量和断层产状。结果显示汶川8.0级地震在平通镇形成的同震垂直位移为3.0±0.1m,右旋水平位移为4.0±0.2m,压缩缩短量为2.5m,断层产状为NE40°/NW∠50°。平通镇的同震右旋位移与本次地震的最大右旋位移相近,而逆冲垂直位移有所降低。
On May 12,2008,a devastating M8.0 earthquake struck Wenchuan County,Sichuan Province.Its seismogenic structure is long the Longmenshan fault zone.Its surface rupture occurs on the Beichuan-Yingxiu and the Jiangyou-Guanxian faults with lengths of 200km and 70km,respectively.The surface rupture at the Pingtong town is a typical form,including co-seismic scarps and echelon fissures on T1and T2 terraces of the Ping River.We surveyed the rupture surface at the site with GPS RTK technique,especially the middle line of the road and the western wall of the fishpond for estimate the co-seismic displacement.We plotted high resolution DEM and large-scale topographic maps.From the DEM and the topographic map we can infer that the co-seismic vertical and strike-slip displacements are 3.0±0.1m and 4.0±0.2m,respectively.The compressed shortening is about 2.5m derived from calculating the original length of the western deformed fishpond wall.At Pington town,the attitude of the seismogenic fault is NE40°/NW∠50°.The strike-slip displacement at Pingtong town is close to the maximum co-seismic strike-slip displacements created by the earthquake,while the vertical one is smaller than the maximum co-seismic vertical displacement.
On May 12,2008,a devastating M8.0 earthquake struck Wenchuan County,Sichuan Province.Its seismogenic structure is long the Longmenshan fault zone.Its surface rupture occurs on the Beichuan-Yingxiu and the Jiangyou-Guanxian faults with lengths of 200km and 70km,respectively.The surface rupture at the Pingtong town is a typical form,including co-seismic scarps and echelon fissures on T1and T2 terraces of the Ping River.We surveyed the rupture surface at the site with GPS RTK technique,especially the middle line of the road and the western wall of the fishpond for estimate the co-seismic displacement.We plotted high resolution DEM and large-scale topographic maps.From the DEM and the topographic map we can infer that the co-seismic vertical and strike-slip displacements are 3.0±0.1m and 4.0±0.2m,respectively.The compressed shortening is about 2.5m derived from calculating the original length of the western deformed fishpond wall.At Pington town,the attitude of the seismogenic fault is NE40°/NW∠50°.The strike-slip displacement at Pingtong town is close to the maximum co-seismic strike-slip displacements created by the earthquake,while the vertical one is smaller than the maximum co-seismic vertical displacement.
引文
1中国地震台网中心(China Earthquake Networks Center).2008.http:∥219.143.71.221/manage/fastReport.jsp-id=8a85532219b131b40119dba5e2c7011b.
2USGS Earthquake Center.2008.http:∥earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008ryan.php.
3马保起,张世民,田勤俭等.汶川8.0级地震地表破裂带.第四纪研究,2008,28(4):513～517Ma Baoqi,Zhang Shimin,Tian Qinjianet al.The surface rupture ofWenchuan Earthquake(M8.0).Quaternary Sciences,2008,28(4):513～517
4任治坤,田勤俭,张军龙.后差分GPS测量则木河断裂地震微地貌特征.地震,2007,27(3):97～104Ren Zhikun,Tian Qinjian,Zhang Junlong.Micro geomorphology of Zemuhe fault surveyed by virtue deferential GPS.Earthquake,2007,27(3):97～104
5张军龙,田勤俭,李智敏等.差分GPS方法在城市活断层探测中的应用探讨.地震,2007,27(3):74～82Zhang Junlong,Tiang Qinjian,Li Zhiminet al.Use of differential GPS in detecting active faults in cities.Earthquake,2007,27(3):74～82
6田勤俭,任治坤,张军龙.则木河断裂带大箐梁子附近古地震组合探槽研究.地震地质,2008,30(2):400～411Tiang Qinjian,Ren Zhikun,Zhang Junlong.Study of paleo-earthquakes by combined trench on Zemuhe fault around Daqinliangzi Xichang,Sichuan.Seismology and Geology,2008,30(2):400～411
7张建华,张灿荣,周江.RTK技术在矿区测量中的应用.地矿测绘,2007,23(2):39～40Zhang Jianhua,Zhang Canrong,Zhou Jiang.Application of RTK technique to mining area survey.Surveying and Mapping ofGeology and Mineral Resources,2007,23(2):39～40
8何宏林,孙昭民,王世元等.汶川MS8.0级地震地表破裂带.地震地质,2008,30(2):359～362He Honglin,Sun Zhaomin,Wang Shiyuanet al.Rupture of the MS8.0Wenchuan Earthquake.Seismology and Geology,2008,30(2):359～362
2USGS Earthquake Center.2008.http:∥earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008ryan.php.
3马保起,张世民,田勤俭等.汶川8.0级地震地表破裂带.第四纪研究,2008,28(4):513～517Ma Baoqi,Zhang Shimin,Tian Qinjianet al.The surface rupture ofWenchuan Earthquake(M8.0).Quaternary Sciences,2008,28(4):513～517
4任治坤,田勤俭,张军龙.后差分GPS测量则木河断裂地震微地貌特征.地震,2007,27(3):97～104Ren Zhikun,Tian Qinjian,Zhang Junlong.Micro geomorphology of Zemuhe fault surveyed by virtue deferential GPS.Earthquake,2007,27(3):97～104
5张军龙,田勤俭,李智敏等.差分GPS方法在城市活断层探测中的应用探讨.地震,2007,27(3):74～82Zhang Junlong,Tiang Qinjian,Li Zhiminet al.Use of differential GPS in detecting active faults in cities.Earthquake,2007,27(3):74～82
6田勤俭,任治坤,张军龙.则木河断裂带大箐梁子附近古地震组合探槽研究.地震地质,2008,30(2):400～411Tiang Qinjian,Ren Zhikun,Zhang Junlong.Study of paleo-earthquakes by combined trench on Zemuhe fault around Daqinliangzi Xichang,Sichuan.Seismology and Geology,2008,30(2):400～411
7张建华,张灿荣,周江.RTK技术在矿区测量中的应用.地矿测绘,2007,23(2):39～40Zhang Jianhua,Zhang Canrong,Zhou Jiang.Application of RTK technique to mining area survey.Surveying and Mapping ofGeology and Mineral Resources,2007,23(2):39～40
8何宏林,孙昭民,王世元等.汶川MS8.0级地震地表破裂带.地震地质,2008,30(2):359～362He Honglin,Sun Zhaomin,Wang Shiyuanet al.Rupture of the MS8.0Wenchuan Earthquake.Seismology and Geology,2008,30(2):359～362
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