地震研究

计算和研究了1973—2014年发生在巴颜喀拉块体东-南边界断裂带上的、由9次MS≥6.3地震组成的强震序列引起的库仑静应力变化图像,分析序列中先发地震破裂对后发地震的应力触发作用。结果表明:(1)1973—1976年在巴颜喀拉块体东边界的虎牙断裂带上发生的4次强震存在着显著的应力触发关系,同时改变了龙门山断裂带中南段及周围区域的应力状态,相继触发了汶川MS8.0地震和芦山MS7.0地震;(2)南边界鲜水河断裂带自1973年以来发生的3次强震同样存在应力触发关系,2014年康定MS6.3地震是巴颜喀拉块体东、南边界强震活动导致的库仑应力变化共同触发的结果;(3)序列中9次地震共同产生的库仑应力变化图像显示:龙门山断裂带南段的汶川地震至芦山地震破裂段之间的空区,鲜水河断裂带南段的道孚地震至康定地震破裂段之间的空区以及鲜水河断裂带、安宁河断裂带、龙门山断裂带交汇的三岔口地区均在库仑应力增加区的覆盖范围之内,需要重点关注。

In this paper,we calculate and map the patterns of Coulomb static stress changes induced by a major earthquake sequence of 9 MS≥6.3 events in the eastern and southern boundary fault zones of the Bayan Har block from 1973 to 2014,and analyze the effects of stress triggering induced by the preceding events to the following events. The results show that,firstly,there is a significant stress triggering relationship in the 4 major earthquakes occurred on Huya fault zone in the eastern boundary of the Bayan Har block from 1973 to 1976,besides,it changed the stress state of the middle-south segment of Longmenshan fault zone as well as surrounding areas,and triggered Wenchuan MS8.0 earthquake and Lushan MS7.0 earthquake one after another; Secondly,there is also coulomb stress triggering relationship existed in the 3 major earthquakes occurred on Xianshuihe fault zone in the southern boundary of Bayan Har block since 1973,and 2014 Kangding MS6.3 earthquake is a common triggering result of coulomb stress change induced by strong earthquake activities in both Bayan Har block's eastern and southern boundaries; Thirdly,the patterns of coulomb stress change caused by the 9 earthquake in the sequence show that,the seismic gap between Wenchuan earthquake and Lushan earthquake in south segment of Longmenshan fault zone,the seismic gap between Daofu earthquake and Kangding earthquake in Xianshuihe fault zone,and the junction region of Xianshuihe-Anninghe-Longmenshan fault zones are all in the increased zone of Coulomb stress changes,thus their future earthquake risks are worth concern.

引言
1 计算原理和方法
2 发震断层与位错模型
3 计算结果及分析
4 结论与讨论

图1 巴颜喀拉块体区域位置(a)及1973—2014年在其东—南边界发生9次强震序列的震源机制解及区域活动构造环境(b)<br/>Fig.1 The regional location of Bayan Har block(a) and a map of the focal mechanism solutions of 9 major earthquake sequence from 1973 to 2014 and regional active tectonic environment in Bayan Har block's eastern and southern boundaries(b)

图1 巴颜喀拉块体区域位置(a)及1973—2014年在其东—南边界发生9次强震序列的震源机制解及区域活动构造环境(b)
Fig.1 The regional location of Bayan Har block(a) and a map of the focal mechanism solutions of 9 major earthquake sequence from 1973 to 2014 and regional active tectonic environment in Bayan Har block's eastern and southern boundaries(b)

表1 1976—2014年巴颜喀拉块体东—南边界强震序列发震断层产状及同震位错参数<br/>Tab.1 Seismogenic fault attitudes and coseismic slips of 9 major events in Bayan Har block's eastern and southern boundaries from 1976 to 2014

表1 1976—2014年巴颜喀拉块体东—南边界强震序列发震断层产状及同震位错参数
Tab.1 Seismogenic fault attitudes and coseismic slips of 9 major events in Bayan Har block's eastern and southern boundaries from 1976 to 2014

图2 巴颜喀拉块体东边界强震序列库仑破裂应力变化图<br/>Fig.2 Maps of Coulomb stress changes induced by major earthquakes in Bayan Har block's eastern boundary

图2 巴颜喀拉块体东边界强震序列库仑破裂应力变化图
Fig.2 Maps of Coulomb stress changes induced by major earthquakes in Bayan Har block's eastern boundary

图3 巴颜喀拉块体南边界强震序列库仑破裂应力变化图像<br/>Fig.3 Maps of Coulomb stress changes induced by major earthquakes in Bayan Har block's southern boundary

图3 巴颜喀拉块体南边界强震序列库仑破裂应力变化图像
Fig.3 Maps of Coulomb stress changes induced by major earthquakes in Bayan Har block's southern boundary

图4 1973年—2014年巴颜喀拉块体东—南边界9次强震序列库仑破裂应力变化图<br/>Fig.4 Maps of Coulomb stress changes induced by major earthquake sequence in Bayan Har block's eastern and southern boundaries

图4 1973年—2014年巴颜喀拉块体东—南边界9次强震序列库仑破裂应力变化图
Fig.4 Maps of Coulomb stress changes induced by major earthquake sequence in Bayan Har block's eastern and southern boundaries

图5 有效摩擦系数μ'为0.2(a)、0.4(b)、0.8(c)对库仑应力变化的影响<br/>Fig.5 The Coulomb stress changes based on different effective coefficient

图5 有效摩擦系数μ'为0.2(a)、0.4(b)、0.8(c)对库仑应力变化的影响
Fig.5 The Coulomb stress changes based on different effective coefficient

图6 计算深度为5 km(a)、10 km(b)、15 km(c)对同震库仑应力变化的影响<br/>Fig.6 The Coulomb stress changes based on different calculated depth of 5 km(a),10 km(b)and 15 km(c)

图6 计算深度为5 km(a)、10 km(b)、15 km(c)对同震库仑应力变化的影响
Fig.6 The Coulomb stress changes based on different calculated depth of 5 km(a),10 km(b)and 15 km(c)

图7 泊松比为0.1(a)、0.25(b)、0.6(c)对同震库仑应力变化的影响<br/>Fig.7 The Coulomb stress changes based on different Poisson ratio of 0.1(a),0.25(b)and 0.6(c)

图7 泊松比为0.1(a)、0.25(b)、0.6(c)对同震库仑应力变化的影响
Fig.7 The Coulomb stress changes based on different Poisson ratio of 0.1(a),0.25(b)and 0.6(c)

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备注

引言

1 计算原理和方法

2 发震断层与位错模型

3 计算结果及分析

4 结论与讨论

期刊信息