川西北断块东部区域活动构造体系及其对地震活动的控制作用
|
摘要
川西北倒三角形断块东部区域地处青藏高原东部边缘地带,跨川西北高原及其与四川盆地过渡带的高山峡谷区。由其南东侧边界活动断裂即龙门山北东向活动断裂带,北侧边界活动断裂即西秦岭近东西向构造带的南缘活动断裂带,断块内部近南北向岷山隆起断裂带的岷江与虎牙断裂等活动断裂带组合,构成了本区由西向东逐渐收敛的平卧“A”字形活动构造体系。在该活动构造体系的控制和强大的近东西向构造应力场的驱动下,川西北断块沿两侧边界活动断裂向东强力楔入,于武都、文县-平武、青川“构造急剧收口带”之西侧,沿东经104°线附近形成了一个近南北向展布、地跨三大构造单元的统一强震活动带。而在该带的东、西两侧地区,地震活动则明显减弱。强震沿该带有规律地南、北往返迁移和重复发生。
The east part of the inverted-triangle-shaped fault block in the northwest of Sichuan is situated in the northeast edge of the Qingzang Plateau. It extends across the northwest plateau of Sichuan and the valley of transitional area between that and Sichuan Basin. The NE-directional active rift zone of the Longmen Mountains is the southeastern boundary active rift zone of the east part of the inverted-triangle-shaped fault block in the northwest of Sichuan. The recent EW-directional active rift zone of the southern margin of the west of Qinling Mountains is its northern boundary active rift zone. The Minjiang River faults and Huya faults which consist of the recent SN-directional active rift zone of the Minshan Mountains are situated inside the east part of the northwest fault block of Sichuan. The three active rift zones consist of A-type active tectonic system controlling earthquakes. The authors discover the seismic activity law of this region. Generally speaking, inlensive seismic activity belts formed near 104°E . Besides, the frequency and maximum earthquake magnitude inside the fault block are higher than those in boundary faults and the seismic intensity in the north is far larger than that in the south. As far as the space is concerned, intensive earthquakes in 104°E can transfer from boundary faults to those inside and vice versa, when it comes to the time, the active period and dormant period alternate and the earthquake whose magnitude is larger than 7.0 tends to accelerate.
The east part of the inverted-triangle-shaped fault block in the northwest of Sichuan is situated in the northeast edge of the Qingzang Plateau. It extends across the northwest plateau of Sichuan and the valley of transitional area between that and Sichuan Basin. The NE-directional active rift zone of the Longmen Mountains is the southeastern boundary active rift zone of the east part of the inverted-triangle-shaped fault block in the northwest of Sichuan. The recent EW-directional active rift zone of the southern margin of the west of Qinling Mountains is its northern boundary active rift zone. The Minjiang River faults and Huya faults which consist of the recent SN-directional active rift zone of the Minshan Mountains are situated inside the east part of the northwest fault block of Sichuan. The three active rift zones consist of A-type active tectonic system controlling earthquakes. The authors discover the seismic activity law of this region. Generally speaking, inlensive seismic activity belts formed near 104°E . Besides, the frequency and maximum earthquake magnitude inside the fault block are higher than those in boundary faults and the seismic intensity in the north is far larger than that in the south. As far as the space is concerned, intensive earthquakes in 104°E can transfer from boundary faults to those inside and vice versa, when it comes to the time, the active period and dormant period alternate and the earthquake whose magnitude is larger than 7.0 tends to accelerate.
引文
[1]蒋良文.岷江上游活动断裂及主要地质灾害研究[D].成都:成都理工大学档案馆,1999.
[2]唐荣昌,韩渭宾.四川活动断裂与地震[M].北京:地震出版社,1993.
[3]林茂炳,苟宗海.四川龙门山造山带造山模式研究[M].成都:成都科技大学出版社,1996.
[4]林茂炳,苟宗海.龙门山中段地质[M].成都:成都科技大学出版社,1996.
[5]陈社发,邓起东,赵小麟.龙门山中段推覆构造带及相关构造的演化历史和变形机制[J].地震地质,1994,16(4):430-462.
[6]吴刚.龙门山推覆构造与地震活动[J].地震研究,1992,15(3):62-69.
[7]邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].北京:地震地质,1994,16(4):429-439.
[8]Okubo P G.Fractal geometry in the San Andressfault system[J].Journal of Geophysical Research,1987,92(11):345-355.
[9]琼斯.1976年松潘地震的震源机制及余震定位[A].松潘地震预报学术讨论会文集[C].北京:地震出版社,1989.22-27.
[10]谢毓寿,程德利,丁学仁.1900~1980年中国M≥4.7级地震的均一震级目录[M].北京:地震出版社,1989.
[11]侣戈培,廖华.四川及邻区地壳垂直形变特征与地震的关系[J].四川地震,1996,(4):109-116.
[12]李建中.川西地区的区域形变与中长期地震趋势[J].四川地震,1995,(4):39-46.
[13]国家地震局.中国地震简目[M].北京:地震出版社,1977.
[14]兰州地震研究所.陕甘宁青四省区强地震目录[M].西安:陕西科技出版社,1985.
[15]四川省地震局.一九三三年叠溪地震[M].成都:四川科学技术出版社,1985.
[16]中科院地球物理所.中国强地震简目[M].北京:地图出版社,1976.
[17]江道崇.龙门山地震带地震活动特征的研究[J].四川地震,1995,(4):10-18.
[18]四川省地震局.一九七六年松潘地震[M].北京:地震出版社,1979.
[19]洪时中,洪时明.地学领域中的分维研究:水系、地震及其它[J].大自然探索,1988,7(24):33-40.
[2]唐荣昌,韩渭宾.四川活动断裂与地震[M].北京:地震出版社,1993.
[3]林茂炳,苟宗海.四川龙门山造山带造山模式研究[M].成都:成都科技大学出版社,1996.
[4]林茂炳,苟宗海.龙门山中段地质[M].成都:成都科技大学出版社,1996.
[5]陈社发,邓起东,赵小麟.龙门山中段推覆构造带及相关构造的演化历史和变形机制[J].地震地质,1994,16(4):430-462.
[6]吴刚.龙门山推覆构造与地震活动[J].地震研究,1992,15(3):62-69.
[7]邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].北京:地震地质,1994,16(4):429-439.
[8]Okubo P G.Fractal geometry in the San Andressfault system[J].Journal of Geophysical Research,1987,92(11):345-355.
[9]琼斯.1976年松潘地震的震源机制及余震定位[A].松潘地震预报学术讨论会文集[C].北京:地震出版社,1989.22-27.
[10]谢毓寿,程德利,丁学仁.1900~1980年中国M≥4.7级地震的均一震级目录[M].北京:地震出版社,1989.
[11]侣戈培,廖华.四川及邻区地壳垂直形变特征与地震的关系[J].四川地震,1996,(4):109-116.
[12]李建中.川西地区的区域形变与中长期地震趋势[J].四川地震,1995,(4):39-46.
[13]国家地震局.中国地震简目[M].北京:地震出版社,1977.
[14]兰州地震研究所.陕甘宁青四省区强地震目录[M].西安:陕西科技出版社,1985.
[15]四川省地震局.一九三三年叠溪地震[M].成都:四川科学技术出版社,1985.
[16]中科院地球物理所.中国强地震简目[M].北京:地图出版社,1976.
[17]江道崇.龙门山地震带地震活动特征的研究[J].四川地震,1995,(4):10-18.
[18]四川省地震局.一九七六年松潘地震[M].北京:地震出版社,1979.
[19]洪时中,洪时明.地学领域中的分维研究:水系、地震及其它[J].大自然探索,1988,7(24):33-40.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心