1997—2003年新疆伽师地震序列时空分布研究
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摘要
分析研究了伽师地震序列目录。分析结果表明:①1997—2003年伽师地震分为3个发震阶段,不同阶段具有各自的活动特点,第一阶段6级地震频次高,第二阶段5级地震频次高,第三阶段地震强度大,高b值是伽师序列明显起伏前的主要特征;②伽师6级地震经历了由西南向北东再向东南的发展过程,1997年4月16日前发生的6级地震余震分布倾向性不显著,其后发生的6级地震的余震大都分布在主震南侧,2003年2月24日伽师6.8级地震余震分布形态与以往6级地震明显不同,这可能与该区特殊的构造条件有关;③1998年以前伽师6级地震余震扩展不明显,1998年8月27日6级地震余震已显现出扩展趋势,2003年2月24日6级地震余震扩展显著;④伽师强震群6级地震震源深度介于17—31km范围,1997年4月16日后震源深度维持在27km左右范围,表明伽师序列初始破裂从上地壳开始,而优势破裂深度在中地壳;⑤伽师地震整体上表现出由浅到深的分布特征,3个活动阶段5级地震也具有这种特征,多数5级以上地震的震源深度正是震区高速体存在区。
We analyzed and studied the catalog of Jiashi earthquake sequence. The result showed: The Jiashi earthquake sequence from 1997 to 2003 was composed by three phases of occurring earthquakes, the different phases had themselves characteristics, the frequency of M6 earthquakes was high in first phase, the frequency of M5 earthquakes was high in second phase, the earthquake intension was high in the third phase, and the main characteristic before the obvious change of Jiashi earthquake sequence was high b value; The developing course of Jiashi earthquake sequence is from SW direction to NE direction to SE direction, the distribution of M6 earthquakes' aftershocks before Apr. 16, 1997 isn't obvious, the aftershocks of most of the later M6 earthquakes in the south of the main earthquakes, the aftershocks' distribution was different between the Jiashi M6.8 earthquake in Feb. 24, 2003 and the other M6 earthquakes, the reason can be the especial construct; The expansion of the aftershocks of Jiashi M6 earthquakes before 1998 wasn't obvious, the obvious expansion trend occurred in the aftershocks of the M6 earthquake in Aug. 27, 1998, the obvious expansion occurred in the aftershocks of the M6 earthquake in Feb.24,2003; the focal depths of the Jiashi strong earthquakes cluster were from 17km to 31km, the focal depths were about 27km after Apr.16,1998, this showed the first fracture of the Jiashi earthquake sequence started from the crust, but the main fracture started from the middle crust; the distribution characteristic of Jiashi earthquake is from shallow to deep, the M5 earthquakes in three phases also had the same characteristic, most of the M5 earthquakes' occurred in the high-speed region.
We analyzed and studied the catalog of Jiashi earthquake sequence. The result showed: The Jiashi earthquake sequence from 1997 to 2003 was composed by three phases of occurring earthquakes, the different phases had themselves characteristics, the frequency of M6 earthquakes was high in first phase, the frequency of M5 earthquakes was high in second phase, the earthquake intension was high in the third phase, and the main characteristic before the obvious change of Jiashi earthquake sequence was high b value; The developing course of Jiashi earthquake sequence is from SW direction to NE direction to SE direction, the distribution of M6 earthquakes' aftershocks before Apr. 16, 1997 isn't obvious, the aftershocks of most of the later M6 earthquakes in the south of the main earthquakes, the aftershocks' distribution was different between the Jiashi M6.8 earthquake in Feb. 24, 2003 and the other M6 earthquakes, the reason can be the especial construct; The expansion of the aftershocks of Jiashi M6 earthquakes before 1998 wasn't obvious, the obvious expansion trend occurred in the aftershocks of the M6 earthquake in Aug. 27, 1998, the obvious expansion occurred in the aftershocks of the M6 earthquake in Feb.24,2003; the focal depths of the Jiashi strong earthquakes cluster were from 17km to 31km, the focal depths were about 27km after Apr.16,1998, this showed the first fracture of the Jiashi earthquake sequence started from the crust, but the main fracture started from the middle crust; the distribution characteristic of Jiashi earthquake is from shallow to deep, the M5 earthquakes in three phases also had the same characteristic, most of the M5 earthquakes' occurred in the high-speed region.
引文
[1]王筱荣,孙甲宁,王季达.1997—2004年伽师地区6级地震序列特征研究[J].内陆地震,2005,19(1):44—52.
[2]单新建,何玉梅,朱燕,等.伽师强震群震源破裂特征的初步分析[J].地球物理学报,2002,45(3):416—424.
[3]高国英,温和平.帕米尔东北侧现代构造应力场与地震活动特征研究[J].中国地震,2000,16(2):176—184.
[4]宋力军,苗崇刚,袁一凡,等.新疆巴楚—伽师6.8级地震灾害损失评估[J].内陆地震,2003,17(2):157—166.
[5]刘正荣,晏风桐.龙陵共轭地震群的特征[J].地震研究,1978,1(2):27—29.
[6]高国英,聂晓红,夏爱国.2003年伽师6.8级地震序列特征和震源机制的初步研究[J].中国地震,2004,20(2):179—186.
[7]黄雍,张建国,乔森.2001年云南施甸中强震群研究[M ].昆明:云南科技出版社,2002.
[8]刘启元,陈九辉,李顺成.新疆伽师强震群区三维地壳上地幔S波速度结构及其地震成因的探讨[J].地球物理学报,2000,43(3):356—365.
[9]朱令人,苏乃秦,杨马陵.1997年新疆伽师强震群及三次成功的临震预报[J].中国地震,1998,14(2):101—115.
[10]赵瑞斌,胡伟华,王坚.1997年伽师地震震害与损失评估[J].内陆地震,1997,11(4);405—410.
[11]单新建,何玉梅,朱燕,等.新疆伽师强震群的震源破裂特征[J].地震地质,2002,24(1):59—68.
[12]梅世蓉,尹京苑.唐山、邢台地震序列特征与三维速度结构的关系[J].地震学报,1999,21(2):159—165.
[13]尹京苑,梅世蓉,薛艳.邢台地区的深部构造对强震孕育影响的三维数值模拟[J].地球物理学报,1999,42(增刊):131—140.
[14]孙若昧,刘福田.京津唐地区地壳结构与强震的发生[J].地球物理学报,1995,38(5):599—607.
[15]尹京苑,梅世蓉,薛艳.邢台地震区地壳结构特征与强震孕育发生关系的探讨[J].地球物理学报,1999,42(5):629—639.
[16]梅世蓉.唐山地震序列的复杂性及成因[J].地震,1995,15(增刊):31—39.
[17]王周元,范世宏,姬凤英,等.甘肃地区地壳速度的非均匀分布[J].西北地震学报,1996,18(2):18—25.
[18]苏有锦,刘祖荫.丽江7.0级地震震源环境及其破裂过程讨论[J].地震研究,1997,20(1):66—71.
[19]胥颐,朱介寿,刘志坚,等.新疆天山及其邻区地壳上地幔三维速度图像[J].地震学报,1994,16(4):480—487.
1朱令人.伽师强震群成因综合研究(96-913-07-04),2000年11月.
[2]单新建,何玉梅,朱燕,等.伽师强震群震源破裂特征的初步分析[J].地球物理学报,2002,45(3):416—424.
[3]高国英,温和平.帕米尔东北侧现代构造应力场与地震活动特征研究[J].中国地震,2000,16(2):176—184.
[4]宋力军,苗崇刚,袁一凡,等.新疆巴楚—伽师6.8级地震灾害损失评估[J].内陆地震,2003,17(2):157—166.
[5]刘正荣,晏风桐.龙陵共轭地震群的特征[J].地震研究,1978,1(2):27—29.
[6]高国英,聂晓红,夏爱国.2003年伽师6.8级地震序列特征和震源机制的初步研究[J].中国地震,2004,20(2):179—186.
[7]黄雍,张建国,乔森.2001年云南施甸中强震群研究[M ].昆明:云南科技出版社,2002.
[8]刘启元,陈九辉,李顺成.新疆伽师强震群区三维地壳上地幔S波速度结构及其地震成因的探讨[J].地球物理学报,2000,43(3):356—365.
[9]朱令人,苏乃秦,杨马陵.1997年新疆伽师强震群及三次成功的临震预报[J].中国地震,1998,14(2):101—115.
[10]赵瑞斌,胡伟华,王坚.1997年伽师地震震害与损失评估[J].内陆地震,1997,11(4);405—410.
[11]单新建,何玉梅,朱燕,等.新疆伽师强震群的震源破裂特征[J].地震地质,2002,24(1):59—68.
[12]梅世蓉,尹京苑.唐山、邢台地震序列特征与三维速度结构的关系[J].地震学报,1999,21(2):159—165.
[13]尹京苑,梅世蓉,薛艳.邢台地区的深部构造对强震孕育影响的三维数值模拟[J].地球物理学报,1999,42(增刊):131—140.
[14]孙若昧,刘福田.京津唐地区地壳结构与强震的发生[J].地球物理学报,1995,38(5):599—607.
[15]尹京苑,梅世蓉,薛艳.邢台地震区地壳结构特征与强震孕育发生关系的探讨[J].地球物理学报,1999,42(5):629—639.
[16]梅世蓉.唐山地震序列的复杂性及成因[J].地震,1995,15(增刊):31—39.
[17]王周元,范世宏,姬凤英,等.甘肃地区地壳速度的非均匀分布[J].西北地震学报,1996,18(2):18—25.
[18]苏有锦,刘祖荫.丽江7.0级地震震源环境及其破裂过程讨论[J].地震研究,1997,20(1):66—71.
[19]胥颐,朱介寿,刘志坚,等.新疆天山及其邻区地壳上地幔三维速度图像[J].地震学报,1994,16(4):480—487.
1朱令人.伽师强震群成因综合研究(96-913-07-04),2000年11月.
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