天山地震带境内外主要断层滑动速率和地震矩亏损分布特征研究

发布时间：2018-02-26 09:33

  本文关键词： 弹性块体 GPS 断层 滑动速率 地震矩亏损　出处：《地球物理学报》2016年05期 　论文类型：期刊论文

【摘要】：本文搜集、整理1998—2013年境内外天山及周边地区(包括中国新疆、哈萨克斯坦、吉尔吉斯斯坦等)500余个GPS观测点数据,采用GAMIT/GLOBK软件对其进行解算和平差计算,并利用了弹性块体模型计算区域块体边界断层闭锁深度、块体运动参数和主要活动断层的滑动速率.研究结果表明,东、西昆仑地震带闭锁深度最大(19km),其次为南天山地区,闭锁深度达到17km,闭锁深度最小的为哈萨克斯坦(13km);各块体相对欧亚板块作顺(逆)时针旋转,旋转速率最大(-0.7208±0.0034°/Ma)为塔里木块体,其围绕欧拉极(38.295±0.019°N,95.078±0.077°E)顺时针方向转动,旋转速率最小为天山东段(0.108±0.1210°/Ma),而天山东、西两段无论是在旋转速率上还是在旋转方向上都有显著的区别.西昆仑断裂带的滑动速率(10.2±2.8mm·a-1)最大,南天山西段滑动速率为9.5±1.8mm·a-1,其东段为3.9±1.1mm·a-1;而北天山东段滑动速率(4.7±1.1mm·a-1)高于北天山西段(3.7±0.9mm·a-1);塔里木盆地南缘的阿尔金断裂带平均滑动速率为7.6±1.4mm·a-1,其结果与阿勒泰断裂带滑动速率(7.6±1.6mm·a-1)基本相当;天山断裂带运动方式主要以挤压为主,而阿尔金、昆仑、阿尔泰以及哈萨克斯坦断裂带均是以走滑运动方式为主,除阿勒泰断裂带走滑方式为右旋以外,其余几个断裂带均为左旋运动.最后,利用主要断裂带的滑动速率计算出各地震带的地震矩变化率以及1900年以来地震矩累计变化量,其结果与利用地震目录计算所得到的地震矩进行比较,判定出各地震带上地震矩均衡分布状态,研究结果显示阿尔金、西昆仑、东昆仑和北天山东段断裂带存在较大的地震矩亏损,均具有发生7级以上地震的可能性,南天山东段和哈萨克斯坦断裂带地震矩亏损相对较小,具有孕育6~7级地震的潜能,而天山西段、阿勒泰地震矩呈现出盈余状态,不具在1~3年内有发生强震的可能.
[Abstract]:This paper collects and collates the data of more than 500 GPS observation points in Tianshan Mountains and its surrounding areas (including Xinjiang, Kazakhstan, Kyrgyzstan, etc.) from 1998 to 2013, and calculates the difference between them by using GAMIT/GLOBK software. The elastic block model is used to calculate the block boundary fault locking depth, block motion parameters and the slip rate of the main active faults. The results show that the East and West Kunlun seismic belt has the largest locking depth of 19 kmg, followed by the South Tianshan area. The atresia depth was 17km, and the minimum latchup depth was 13kmm of Kazakstan. Each block rotated clockwise relative to the Eurasian plate. The maximum rotation rate was -0.7208 卤0.0034 掳/ Ma. it was a Tarim block, and it rotated clockwise around the Euler pole (38.295 卤0.019 掳N95.078 卤0.077 掳E). The minimum rotation rate is 0.108 卤0.1210 掳/ m ~ (-1) in the eastern segment of Tianshan Mountain, but there are significant differences in rotation rate and direction of rotation between the two segments in Tianshan and Shandong. The slip rate of the West Kunlun fault zone is 10.2 卤2.8 mm 路a ~ (-1). The slip rate of the southern Tianshan Shanxi section is 9.5 卤1.8 mm 路a -1 and the eastern segment 3.9 卤1.1 mm 路a -1, while the eastern segment of the North Tianshan Mountain is 4.7 卤1.1 mm 路a -1) higher than that of the western part of the North Tianshan Mountain, and the average slip rate of the Altun fault zone in the southern margin of the Tarim Basin is 7.6 卤1.4 mm 路a -1, which is basically equivalent to that of the Aletai fault zone (7.6 卤1.6 mm 路a -1). The Tianshan fault zone is mainly driven by compression, while the Altun, Kunlun, Altai and Kazakstan fault zones are mainly strike-slip, except for the Altay fault zone, where the strike-slip pattern is dextral. The other fault zones are all left-handed motion. Finally, the seismic moment variation rate of each seismic zone and the accumulative variation of seismic moment since 1900 have been calculated by using the sliding rate of the main fault zone. The results are compared with the seismic moments obtained by using earthquake cataloguing, and the equilibrium distribution of seismic moments on each seismic belt is determined. The results show that Altun and West Kunlun, The fault zone of East Kunlun and North Tianshan has a large seismic moment deficit, both of which have the possibility of occurrence of earthquakes with M 鈮，

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