| 西南天山东柯坪推覆系古地震初步研究 |
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| 引用本文： | 李安,冉勇康,徐良鑫,刘华国,李彦宝.西南天山东柯坪推覆系古地震初步研究[J].地震地质,2011(4):752-764. |
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| 作者姓名： | 李安 冉勇康 徐良鑫 刘华国 李彦宝 |
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| 作者单位： | 中国地震局地质研究所国家地震活动断层研究中心 |
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| 基金项目： | 国家自然科学基金(40872130);财政部重大专项“我国重点监视防御区活动断层地震危险性评价”共同资助 |
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| 摘 要： | 西南天山柯坪推覆系发育多排逆断裂-褶皱带,各排逆断裂-褶皱带的变形速率并不一致,古地震发生规律也可能具有不同特点.自汶川地震造成龙门山中央和前山两条断裂同时活动之后,对于如何判断多条逆断裂级联破裂的逆断裂古地震事件,是一个值得讨论的问题.文中通过对东柯坪塔格和萨尔干塔格两排逆断裂-褶皱带山前多期地貌面(冲洪积扇面)上发...
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| 关 键 词： | 古地震 10Re暴露年龄 天山 柯坪 |
A PRELIMINARY STUDY ON PALEOEARTHQUAKES IN THE EASTERN KALPIN NAPPE SYSTEM,SOUTHWESTERN TIANSHAN,CHINA |
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| I AnRAN,ong-U Liang-xinLIU,ua-guoLI Yan-bao.A PRELIMINARY STUDY ON PALEOEARTHQUAKES IN THE EASTERN KALPIN NAPPE SYSTEM,SOUTHWESTERN TIANSHAN,CHINA[J].Seismology and Geology,2011(4):752-764. |
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| Authors: | I AnRAN ong-U Liang-xinLIU ua-guoLI Yan-bao |
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| Institution: | (National Center for Active Fault Studies,Institute of Geology,China Earthquake Administration,Beijing100029,China) |
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| Abstract: | There are several thrust-fold belts developed in the Kalpin nappe system of the southwestern Tianshan Mountains.Not only deformation rates of these thrust-fold belts are inconsistent,but also the paleoearthquakes recurrence laws on these thrust-fold belts in the nappe system are different.The Beichuan-Yingxiu Fault and the Pengguan Fault ruptured simultaneously in the Mw 7.9 Wenchuan earthquake.Therefore,it is worth discussing the question of how to determine the cascade-rupturing of a paleoearthquake on two or three thrust faults.We measured the scraps of different heights on the geomorphic surfaces(alluvial-proluvial fans)of different stages in eastern Kalpintage and Saergantage and analyzed the paleoearthquake events revealed by trenches in Shanchakou and Saergantage.Using the10Be exposure age,we obtained the ages of the geomorphic surfaces.Then we got the upper and lower limit time of each paleoearthquake from the age of adjacent geomorphic surfaces.Finally,we got the recurrence intervals of different paleoearthquakes,the vertical dislocation of a single event,and the time range of the respective events.The results show that since 20kaBP,the average recurrence interval of paleoearthquake in the piedmont of east Kalpintage is 6.7±0.84ka,the vertical dislocation of a single event is 1m;the average recurrence interval of paleoearthquake in the piedmont of Saergantage is 5.4±0.50ka,and the vertical dislocation of a single event is 0.8～1.2m.The intensity of paleoseismicity is basically identical and the recurrence interval in Saergantage is slightly shorter.In the end,we discussed the possibility of cascade-rupturing accompanying these paleoearthquake events and found that the second and the third paleoearthquake events revealed by the trenches overlap in their occurrence time ranges,indicating the possibility of cascade-rupturing during the earthquake. |
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| Keywords: | paleoearthquake 10Be exposure age Tianshan Mountains Kalpin |
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