1990: SOURCE PARAMETERS OF SMALL EARTHQUAKES BEFORE AND AFTER THE 1982 LULONG EARTHQUAKE. Acta Seismologica Sinica, 12(1): 1-11.
Citation: 1990: SOURCE PARAMETERS OF SMALL EARTHQUAKES BEFORE AND AFTER THE 1982 LULONG EARTHQUAKE. Acta Seismologica Sinica, 12(1): 1-11.

SOURCE PARAMETERS OF SMALL EARTHQUAKES BEFORE AND AFTER THE 1982 LULONG EARTHQUAKE

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  • Published Date: September 01, 2011
  • On 19 October 1982,an earthquake (3957'N,11904'E) with ML = 6.2 (according to Catalog of the Beijing Telemetered Seismic Network) occurred in Lulong on the northeastern edge of the aftershock zone of the Tangshan 7.8 earthquake of 1976. Earthquakes in the Tangshan-Lulong region from January 1980 to June 1984 have been examined for monitoring the variations in source parameters of small earthquakes before and after the Lulong earthquake. Source parameters of 160 earthquakes,2.7ML4.3,were determined using the P-wave first motions. In the magnitude range studied the P-wave first impulse width and the source radius do not increase with ML,and the stress drop increases with ML. The values of stress drop vary in the range from 0.1 MPa to 50 MPa,and are concentrated primarily between 1 MPa and 5 MPa; so in this paper stress drops of 5 MPa and more are taken as high stress drops and that of 1 MPa and less as low stress drops for this region. The spatial distribution of earthquakes in this region shows an apparent relation between high stress drop events and succedent ML5 earthquakes. Within one year and more before the Lulong earthquake,in the vicinity of its epicenter occurred two high-stress drop events,but in the whole reigon the number of high-stress-drop events decreased and that of low-stress-drop events increased.
  • [1] 陈运泰、林邦慧、李兴才等,1976.巧家、石棉的小震震源参数的测定及其地震危险性的估计.地球物理学报,19,206——233,

    [2] 朱传镇、傅昌洪、罗胜利,1977,唐山7.8级地震前后微震震源参数.地球物理学报,20,264——269,

    [3] Bakun, W. H., Bufr, C. G., and Stewart, R. M., 1981. P——wave spectra from d1a5 furcshocks and isolated earthquakes near Parkfield, California. Bull. Seism. Sov. Amer,71, 423——436.

    [4] O'Neill, N. E., 1984. Source dimension and stress drop of small earthquakes near Parkfield, California.Bull. Seism. Soc, Amer., 74, 27——40.

    [5] Frankel, A,and Knnamori, H., 1983. Determinatiion of rupture duration and stress drop for earthquakes in Southern California. Bull. Seism. Soc. Amen, 73, 1527——1551.

    [6] Boatwright, J., 1980. A special theory for circular seismic sources, Simple estimates of source dimension,dynamic stress drop and radiated seismic energy, Bull. Seism. Sac, Ainer., 74, 1——28.

    [7] 中国科学院地球物理研究所,1977.近震分析,256,地震出版社.

    [8] 韦士忠、陈培善、辛书义,1986.由中小地震波谱研究华北北部地区的应力场和地震危险性,中国地震学会第三次全国地震科学学术讨论会论文摘要汇编,35——37,

    [9] Brune, J. N., 1970. Tectonic stress and the spectra of seismic waves from earthquakes. J. Geophys Re.s.,75. 4997——5009.

    [10] Schcrbaum, F., and Stoll, D., 1983. The 1978 Stwabian Jura aftershocks B+ll Scrsm. Sac. Amer.73,1321——1343.

    [11] Archulata, R. J., Cranswick, E., Mueller, C., and Spudiclt. P., 1982. Source parameters of the 1980 Mammoth Lakes, California, earthquake sequence, J. Gcophyr. Res,87. 4595——4607.

    [12] Aki,K 1967. Scaling law of seismic spectrum. .l. Geophys. Rer., 72. 1217——1230.

    [13] Chouet, B., and Aki, K., 1978. Regional variation of the scaling law of eartliqnake source spectra. Bull.Seism.. Sor. Amcr.,68, 49——79.

    [14] Zobin, V. M、1986. Variation in source parameters of small earthquakes before large earthquakes. Tectonaphysicr, 126, 229——243.

    [1] 陈运泰、林邦慧、李兴才等,1976.巧家、石棉的小震震源参数的测定及其地震危险性的估计.地球物理学报,19,206——233,

    [2] 朱传镇、傅昌洪、罗胜利,1977,唐山7.8级地震前后微震震源参数.地球物理学报,20,264——269,

    [3] Bakun, W. H., Bufr, C. G., and Stewart, R. M., 1981. P——wave spectra from d1a5 furcshocks and isolated earthquakes near Parkfield, California. Bull. Seism. Sov. Amer,71, 423——436.

    [4] O'Neill, N. E., 1984. Source dimension and stress drop of small earthquakes near Parkfield, California.Bull. Seism. Soc, Amer., 74, 27——40.

    [5] Frankel, A,and Knnamori, H., 1983. Determinatiion of rupture duration and stress drop for earthquakes in Southern California. Bull. Seism. Soc. Amen, 73, 1527——1551.

    [6] Boatwright, J., 1980. A special theory for circular seismic sources, Simple estimates of source dimension,dynamic stress drop and radiated seismic energy, Bull. Seism. Sac, Ainer., 74, 1——28.

    [7] 中国科学院地球物理研究所,1977.近震分析,256,地震出版社.

    [8] 韦士忠、陈培善、辛书义,1986.由中小地震波谱研究华北北部地区的应力场和地震危险性,中国地震学会第三次全国地震科学学术讨论会论文摘要汇编,35——37,

    [9] Brune, J. N., 1970. Tectonic stress and the spectra of seismic waves from earthquakes. J. Geophys Re.s.,75. 4997——5009.

    [10] Schcrbaum, F., and Stoll, D., 1983. The 1978 Stwabian Jura aftershocks B+ll Scrsm. Sac. Amer.73,1321——1343.

    [11] Archulata, R. J., Cranswick, E., Mueller, C., and Spudiclt. P., 1982. Source parameters of the 1980 Mammoth Lakes, California, earthquake sequence, J. Gcophyr. Res,87. 4595——4607.

    [12] Aki,K 1967. Scaling law of seismic spectrum. .l. Geophys. Rer., 72. 1217——1230.

    [13] Chouet, B., and Aki, K., 1978. Regional variation of the scaling law of eartliqnake source spectra. Bull.Seism.. Sor. Amcr.,68, 49——79.

    [14] Zobin, V. M、1986. Variation in source parameters of small earthquakes before large earthquakes. Tectonaphysicr, 126, 229——243.
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