震源介质参数的连续监测及其在张北地震前的变化
|
摘要
通过对首都圈地区的小震复合震源机制、尾波 Q值和波速比三项震源介质参数的连续监测发现 ,在 1 998年 1月 1 0日河北张北 6.2级地震前 ,1 997年小震复合机制解的矛盾符号比达到了历年的最低点 ,且其方向接近于张北地震由初动得到的震源机制方向 ;山西恒山台 30～ 60 s时间窗的尾波 Q0 于 1 997年出现了较高的值 ;张北地区自 1 995年 1月至 1 997年 3月 ,存在 2 7个月的 VP/VS的低值异常。这些结果除可直接作为前兆现象用于地震预测外 ,对于理解地震孕育发生的物理过程也是很有意义的
Continuously monitoring the composite focal mechanism, coda Q and seismic wave velocity ratio, we have found that the inconsistency ratio of composite focal mechanism in 1997 reached its lowest value over the years and its direction similar to the Zhangbei earthquake. The coda Q 0 for 30 60s time window in 1997 is higher than before and the wave velocity ratio from February of 1995 to March of 1997 were lower than usual. These variations can be used as precursors to predict earthquake, also are helpful for us to understand the physical process of earthquake preparation and development.
Continuously monitoring the composite focal mechanism, coda Q and seismic wave velocity ratio, we have found that the inconsistency ratio of composite focal mechanism in 1997 reached its lowest value over the years and its direction similar to the Zhangbei earthquake. The coda Q 0 for 30 60s time window in 1997 is higher than before and the wave velocity ratio from February of 1995 to March of 1997 were lower than usual. These variations can be used as precursors to predict earthquake, also are helpful for us to understand the physical process of earthquake preparation and development.
引文
[1 ] 许忠淮 ,阎明 ,赵仲和 .由多个小震推断的华北地区构造应力场的方向 [J].地震学报 ,1 983,5(3) :2 68- 2 79.
[2 ] 黄雨蕊 ,高阿甲 ,许忠淮 .地震震源机制的研究应用于地震预报的探索 [J].地震地磁观测与研究 ,1 997,1 8(1 ) :52 - 57.
[3] 华祥文 .唐山强震前后北京、天津周围地区应力的变化过程 [J],地震学报 ,1 980 ,2 (2 ) :1 30 - 1 45.
[4] 阎明 .区域小震平均节面解的时空分析 [J].地震学报 ,1 991 ,1 3(1 ) :1 0 - 2 0 .
[5] Jin A,Aki K. Observational and physical bases for the coda Q- 1 precursor[A]. In Evaluation ofproposed earthquake precursors(ed M. Wyss) [C]. AGU,1 991 ,Washington,DC. 33- 53.
[6] Chouet B,Aki K ,Tsujiura M. Regional variation of the scaling law of earthquake source spectra[J].Bull Seism Soc Am,1 978,68:49- 79.
[7] Sato H. Temporal changes in scattering and attenuation associated with the earthquakeoccurrence— a review of recent studies on coda waves[J].Pure Appl Geopfys,1 988,1 2 6:465-497.
[8] Jin A,Aki K.Temporal change in coda before the Tangshan earthquake of1 976and the haichengearthquake of1 975[J].JGeophys Res,1 986,91 :665- 673.
[9] Novelo- Casanova D A,Berg E,Hsu V ,et al .Time- space variation seismic S- wave codaattenuation(Q- 1 ) and magnitude distribution(b- values) for the Petatlan earthquake[J].GeophysRes lett,1 985,1 2 :789- 792 .
[1 0 ] Peng JY,Aki K,Lee W H K,et al .Temporal change in coda Q associated with 1 984RoundValley earthquake in California[J].JGeophys Res,1 987,92 :350 7- 3536.
[1 1 ] Hellweg M,Spudich P,Fletcher J B,et al .Stability of coda Q in the region of Parkfield,California:View from the U.S. Geological Survey Parkfield Dense Seismograph Array[J]. JGeophys Res,1 995,1 0 0 (B2 ) :2 0 89- 2 1 0 2 .
[1 2 ] Beroza G C,Cole A T ,Ellsworth W L. Stability of coda wave attenuation during the Loma Prieta,California,earthquake sequence[J].JGeophys Res,1 995,1 0 0 (B3) :3977- 3987
[1 3] 马云生 ,张天中 ,张焕生 .北京及其周围地区尾波 Q值分布特征的研究 [J].地震学报 ,1 995,1 7(4) :448- 458.
[1 4] 王筱荣 ,魏若萍 .用地震波参数预测地震的实践 [J].地震 ,1 997,1 7(1 ) :75- 79.
[1 5] Gusev A A.Temporal variations of the coda decay rate on Kamchatka:Are they real andprecursory?[J].JGeophys Res,1 997,1 0 2 (B4) :8381 - 8396.
[1 6] Tselentis,G- Akis.Evidence for stability in coda Q associated with the Egion(Central Greece)earthquake of 1 5June 1 995[J].Bull Sism Soc Am,1 997,87(6) :1 679- 1 684.
[1 7] 马云生 ,黄蓉良 ,张天中 ,等 .华北地区尾波 Q值分布特征及其准实时监测 [J].地震地磁观测与研究 ,1 998,1 9(1 A) :62 - 66.
[1 8] 李清林 ,张文玉 .张北 6.2级地震及晋北地区的重力场变化 [A].中国地震学会 .第七次学术大会论文摘要集 [C].北京 :地震出版社 ,1 998.1 0 6.
[1 9] 力武常次 .地震预报 [M].冯锐 ,周新华译 .北京 :地震出版社 ,1 978.1 2 3- 1 2 8.
[2 0 ] Wyss M.Second round of evaluations of proposed earthquake precusors[J].PAGEOPH,1 997,1 49:3- 1 6
[2 ] 黄雨蕊 ,高阿甲 ,许忠淮 .地震震源机制的研究应用于地震预报的探索 [J].地震地磁观测与研究 ,1 997,1 8(1 ) :52 - 57.
[3] 华祥文 .唐山强震前后北京、天津周围地区应力的变化过程 [J],地震学报 ,1 980 ,2 (2 ) :1 30 - 1 45.
[4] 阎明 .区域小震平均节面解的时空分析 [J].地震学报 ,1 991 ,1 3(1 ) :1 0 - 2 0 .
[5] Jin A,Aki K. Observational and physical bases for the coda Q- 1 precursor[A]. In Evaluation ofproposed earthquake precursors(ed M. Wyss) [C]. AGU,1 991 ,Washington,DC. 33- 53.
[6] Chouet B,Aki K ,Tsujiura M. Regional variation of the scaling law of earthquake source spectra[J].Bull Seism Soc Am,1 978,68:49- 79.
[7] Sato H. Temporal changes in scattering and attenuation associated with the earthquakeoccurrence— a review of recent studies on coda waves[J].Pure Appl Geopfys,1 988,1 2 6:465-497.
[8] Jin A,Aki K.Temporal change in coda before the Tangshan earthquake of1 976and the haichengearthquake of1 975[J].JGeophys Res,1 986,91 :665- 673.
[9] Novelo- Casanova D A,Berg E,Hsu V ,et al .Time- space variation seismic S- wave codaattenuation(Q- 1 ) and magnitude distribution(b- values) for the Petatlan earthquake[J].GeophysRes lett,1 985,1 2 :789- 792 .
[1 0 ] Peng JY,Aki K,Lee W H K,et al .Temporal change in coda Q associated with 1 984RoundValley earthquake in California[J].JGeophys Res,1 987,92 :350 7- 3536.
[1 1 ] Hellweg M,Spudich P,Fletcher J B,et al .Stability of coda Q in the region of Parkfield,California:View from the U.S. Geological Survey Parkfield Dense Seismograph Array[J]. JGeophys Res,1 995,1 0 0 (B2 ) :2 0 89- 2 1 0 2 .
[1 2 ] Beroza G C,Cole A T ,Ellsworth W L. Stability of coda wave attenuation during the Loma Prieta,California,earthquake sequence[J].JGeophys Res,1 995,1 0 0 (B3) :3977- 3987
[1 3] 马云生 ,张天中 ,张焕生 .北京及其周围地区尾波 Q值分布特征的研究 [J].地震学报 ,1 995,1 7(4) :448- 458.
[1 4] 王筱荣 ,魏若萍 .用地震波参数预测地震的实践 [J].地震 ,1 997,1 7(1 ) :75- 79.
[1 5] Gusev A A.Temporal variations of the coda decay rate on Kamchatka:Are they real andprecursory?[J].JGeophys Res,1 997,1 0 2 (B4) :8381 - 8396.
[1 6] Tselentis,G- Akis.Evidence for stability in coda Q associated with the Egion(Central Greece)earthquake of 1 5June 1 995[J].Bull Sism Soc Am,1 997,87(6) :1 679- 1 684.
[1 7] 马云生 ,黄蓉良 ,张天中 ,等 .华北地区尾波 Q值分布特征及其准实时监测 [J].地震地磁观测与研究 ,1 998,1 9(1 A) :62 - 66.
[1 8] 李清林 ,张文玉 .张北 6.2级地震及晋北地区的重力场变化 [A].中国地震学会 .第七次学术大会论文摘要集 [C].北京 :地震出版社 ,1 998.1 0 6.
[1 9] 力武常次 .地震预报 [M].冯锐 ,周新华译 .北京 :地震出版社 ,1 978.1 2 3- 1 2 8.
[2 0 ] Wyss M.Second round of evaluations of proposed earthquake precusors[J].PAGEOPH,1 997,1 49:3- 1 6
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