在格陵地区地震图上记录到的一个附加震相-i 震相的特征(英文)
|
摘要
在１９７６ —１９８３ 年期间， 格陵兰地区共记录到５３ 个３ ～５ 级地震， 确定了所有的地震参数， 分析了２９ 个地震的震相到时， 得到了该地区Ｐｎ ， Ｐｇ， Ｐ１１ （ＰＭＰ） ， Ｓｎ 和Ｌｇ 震相的走时曲线及其视速度值， 该结果与加拿大走时曲线相一致。发现一部分地震图上在直达波Ｐ与Ｓ之间记录到一个附加的震相—ｉ， ｉ 震相的存在与震中距， 震源深度有关。初步的物理解释是：ｉ 震相可解释成为（Ｐｓ） 或（Ｓｐ） 转换波。该转换波发生在台站下面的低速松散沉积层的底部。
During the period 1976-1983, there have been recorded 53 earthquakes with magnitude from 3 to 5 in Greenland. All of the seismic parameters have been determined, 29 earthquakes′arrival times have been analyzed. The travel time charts and the apparent velocity values of Pn,Pg,PMP,Sn,Lg in Greenland have been obtained. The results coincide with those of Canada′s. An extra phase “i-phase”between the direct P and S waves has been found from some seismograms. I-phases existence is dependent on distance of epicentre, depth of focus. The primary physical explanation is that the i-phase can be interpreted as P-to-S(Ps)or S-to-P(Sp)converted waves generated at the bottom of the low velocity unconsolidated sediments under station.
During the period 1976-1983, there have been recorded 53 earthquakes with magnitude from 3 to 5 in Greenland. All of the seismic parameters have been determined, 29 earthquakes′arrival times have been analyzed. The travel time charts and the apparent velocity values of Pn,Pg,PMP,Sn,Lg in Greenland have been obtained. The results coincide with those of Canada′s. An extra phase “i-phase”between the direct P and S waves has been found from some seismograms. I-phases existence is dependent on distance of epicentre, depth of focus. The primary physical explanation is that the i-phase can be interpreted as P-to-S(Ps)or S-to-P(Sp)converted waves generated at the bottom of the low velocity unconsolidated sediments under station.
引文
〔1〕Gregersen, S. (1982) Earthquakesin Greenland ,Bull.geol.Sco.Denmark vol. 31 ,pp .11 - 27
〔2〕Smith , W. E. T. and W. G. Milne (1970) canadian Earthquakes- 1965 , Seism .Seism Dom . Obs. 1965 - 2 , 1- 38
〔3〕Chen , K. G., J. M. Chiu, and Y. T. Yang (1994) Qp - Qs Relationinthe Sedimentary Basin ofthe upper MississippiEmbayment using Converted phases,Bull.Seism . Soc. Am . 84 , 1861 - 1868
〔4〕Chen ,K. G., J. M. Chiu ,and Y. T. Yang (1996) Shear- Wave Velocity ofthe Sedimentary Basininthe upper Mississippi Embayment using S-to- PConverted Waves,Bull. Seism .Soc.Am . 86 , 848 - 856
〔2〕Smith , W. E. T. and W. G. Milne (1970) canadian Earthquakes- 1965 , Seism .Seism Dom . Obs. 1965 - 2 , 1- 38
〔3〕Chen , K. G., J. M. Chiu, and Y. T. Yang (1994) Qp - Qs Relationinthe Sedimentary Basin ofthe upper MississippiEmbayment using Converted phases,Bull.Seism . Soc. Am . 84 , 1861 - 1868
〔4〕Chen ,K. G., J. M. Chiu ,and Y. T. Yang (1996) Shear- Wave Velocity ofthe Sedimentary Basininthe upper Mississippi Embayment using S-to- PConverted Waves,Bull. Seism .Soc.Am . 86 , 848 - 856
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