The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Bas...The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Based on three trenches, four Holocene palaeo-earthquake events are identified along the Maqu fault. The latest palaeo-earthquake event is (1730±50) ～ (1802±52) a BP, the second is (3736±57) ～ (4641±60) a BP, the third is (8590±70) a BP, and the earliest is (12200±1700) ka BP. The time of the first and second palaeo-earthquake events is more reliable than that of the third and last ones. As a result, the recurrence interval of the palaeo-earthquakes on the easternmost segment of the East Kunlun active fault is approximately 2400 a, and the palaeo-earthquake elapsed time is (1730±50) ～ (1802±52) a BP.展开更多
The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global P...The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System（GPS） measurements of offset river terraces, and 14 C dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3–5 mm/a, and that the vertical slip rate is 0.3–0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of ~100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0–7.5 on the Maqu fault could generate a horizontal slip of 4.5–5 m and a vertical slip of 0.45–0.5 m, with a corresponding ratio（Dh/Dv） of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.展开更多
为研究东昆仑断裂玛沁-玛曲段的活动特征,利用双差定位法对东昆仑断裂玛沁-玛曲段2009-01~2018-09中小地震进行重新定位,并基于CAP(cut and paste)方法反演研究区域3.5级以上地震的震源机制解。结果显示,地震活动沿断裂带分段特征明显,...为研究东昆仑断裂玛沁-玛曲段的活动特征,利用双差定位法对东昆仑断裂玛沁-玛曲段2009-01~2018-09中小地震进行重新定位,并基于CAP(cut and paste)方法反演研究区域3.5级以上地震的震源机制解。结果显示,地震活动沿断裂带分段特征明显,在101°E附近地震沿阿万仓断裂分布,近10 a来玛沁至若尔盖的地震空区现象还在持续;东昆仑断裂玛沁-玛曲段震源深度主要分布在2~30 km范围内;研究区域主压应力为NEE向,主张应力为NNW向。研究结果为东昆仑断裂玛沁-玛曲段因受阿万仓断裂的吸收转换导致在玛沁-玛曲段滑动速率减弱的结论提供了地震学方面的证据。展开更多
基金The project wasjointlysupported bythefollow-up projectsof moderately strong earthquake prediction of the North-South earthquake zone of China Earthquake Administration,theJoint Earthquake Science Foundation of CEA (104073) and the National Natural science Foundation of China(40372086) .Contribution No.LC20060016 of Lanzhou Institute of Seismology of CEA
文摘The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Based on three trenches, four Holocene palaeo-earthquake events are identified along the Maqu fault. The latest palaeo-earthquake event is (1730±50) ～ (1802±52) a BP, the second is (3736±57) ～ (4641±60) a BP, the third is (8590±70) a BP, and the earliest is (12200±1700) ka BP. The time of the first and second palaeo-earthquake events is more reliable than that of the third and last ones. As a result, the recurrence interval of the palaeo-earthquakes on the easternmost segment of the East Kunlun active fault is approximately 2400 a, and the palaeo-earthquake elapsed time is (1730±50) ～ (1802±52) a BP.
基金support of the Natural Science Foundation of China(41472178)the China Geological Survey projects(1212011120167,12120114002211)
文摘The Late Quaternary slip rate along the Maqu segment of the eastern Kunlun Fault was estimated using a combination of high-resolution remote sensing imagery interpretation, field observations and differential Global Positioning System（GPS） measurements of offset river terraces, and 14 C dating of snail shells collected from offset risers. The results show that the left-slip rate along the segment is 3–5 mm/a, and that the vertical slip rate is 0.3–0.5 mm/a. Both the horizontal and vertical slips on the segment remain consistent over a distance of ~100 km. It means that no slip gradient as previously suggested occurred along the Maqu segment, and which thus might behave as an independent seismogenic fault. Judging from multiple relationships among young terrace offsets, we infer that co-seismic surface rupture produced by a characteristic earthquake with a magnitude of Ms7.0–7.5 on the Maqu fault could generate a horizontal slip of 4.5–5 m and a vertical slip of 0.45–0.5 m, with a corresponding ratio（Dh/Dv） of about 9. Two surface rupture events must have occurred over the past 3300 years, the latest one possibly between 1485 cal BP and 1730 cal BP.
文摘为研究东昆仑断裂玛沁-玛曲段的活动特征,利用双差定位法对东昆仑断裂玛沁-玛曲段2009-01~2018-09中小地震进行重新定位,并基于CAP(cut and paste)方法反演研究区域3.5级以上地震的震源机制解。结果显示,地震活动沿断裂带分段特征明显,在101°E附近地震沿阿万仓断裂分布,近10 a来玛沁至若尔盖的地震空区现象还在持续;东昆仑断裂玛沁-玛曲段震源深度主要分布在2~30 km范围内;研究区域主压应力为NEE向,主张应力为NNW向。研究结果为东昆仑断裂玛沁-玛曲段因受阿万仓断裂的吸收转换导致在玛沁-玛曲段滑动速率减弱的结论提供了地震学方面的证据。
