青藏块体东北缘平均波速比的测定及研究
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摘要
利用兰州数字地震遥测台网观测报告,采用和达法计算出2001年1月—2007年6月发生在青藏块体东北缘2 953次地震的波速比值。将青藏块体东北缘按1°×1°、0.2°×0.2°分成小区,求出每个小区域内的平均波速比值。分析得出如下结论:(1)青藏块体东北缘平均波速比值在空间分布上有一定差异,甘东南(N34°以南)波速比值最高,祁连山地震带和西秦岭北缘断裂附近次之,甘肃中部最低;(2)青藏块体东北缘矿震分布区域和1°×1°的低波速比值区域一致,地震波速比值是判定矿震的可能依据之一;(3)地震波速比值随震级的增大而增大。所得的平均波速比值为研究青藏块体东北缘波速比值随时间变化有一定参考价值。
Based on the Lanzhou seismic network observational report,using the multi-station methods,the seismic velocity ratio(VP/VS) of the 2 953 earthquakes in Northeastern margin of Qinghai-Tibet block during Jan.2001 to Jun.2007 are calculated.The research region are divided into little areas by 1°×1° and 0.2°×0.2°,and the average seismic velocity ratios for every little areas are given.Through analysising the average seismic velocity ratios,following conclusion are gottern:(1) The average ratios in different regions of the research block are different,among them,the ratio in Southeastern of Gansu province is the highest,in Qilian seismic belt and along West Qinling fault are higher also,in middle Gansu province is the lowest.(2) The mine earthquakes often occurred in the 1°×1° little areas with lower ratios,so the ratio could be used to distinguish mine earthquake.(3) The ratio values increase along with the increase of magnitudes of earthquake.The average seismic velocity ratios for each area in Northeastern margin of Qinghai-Tibet block can be a reference to analyze the variation of the ratio before strong earthquakes.
Based on the Lanzhou seismic network observational report,using the multi-station methods,the seismic velocity ratio(VP/VS) of the 2 953 earthquakes in Northeastern margin of Qinghai-Tibet block during Jan.2001 to Jun.2007 are calculated.The research region are divided into little areas by 1°×1° and 0.2°×0.2°,and the average seismic velocity ratios for every little areas are given.Through analysising the average seismic velocity ratios,following conclusion are gottern:(1) The average ratios in different regions of the research block are different,among them,the ratio in Southeastern of Gansu province is the highest,in Qilian seismic belt and along West Qinling fault are higher also,in middle Gansu province is the lowest.(2) The mine earthquakes often occurred in the 1°×1° little areas with lower ratios,so the ratio could be used to distinguish mine earthquake.(3) The ratio values increase along with the increase of magnitudes of earthquake.The average seismic velocity ratios for each area in Northeastern margin of Qinghai-Tibet block can be a reference to analyze the variation of the ratio before strong earthquakes.
引文
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[11]王德利,雍运动,韩立国,等.三维粘弹性介质地震波场有限差分并行模拟[J].西北地震学报,2007,29(1):30-34.
[12]粟生平,傅征祥.华北地区地震带分段波速比平均值的测定[J].地震,1996,16(2):114-120.
[13]秦保燕,张元生.波速比异常空间演化与主震位置预测[J].西北地震学报,2000,22(1):5-9.
[14]张学民,刁桂苓,束沛镒,等.华北地区地下介质波速比值(VP/VS)研究[J].地震地质,2004,26(2).305-317.
[15]李光泉,李伟东,施行觉,等.流体分布对松散介质中P波速度和衰减的影响[J].西北地震学报,2000,22(4):361-367
[16]荣棉水,李小军,卢滔.局部地形对入射P波谱特性的影响分析[J].西北地震学报,2007,29(4):297-302.
[2]蔡静观,梅世蓉,张喜玲,等.从高波速比试论云南丽江7级地震的孕震模式[J].地震研究,1999,22(2):122-129.
[3]傅征祥,程燕.北京和张家口地区地壳平均波速比的联合测定[J].地震,1988,8(4):28-34.
[4]嘉世旭,刘昌铨.邢台震源区波速比异常与地震的关系[J].地震学报,1996,39(增刊):205-215.
[5]黎明晓,张晓东.应用多台法测定华北地区地壳的平均波速比[J].地震,2004,24(1):163-169.
[6]李敏莉,刘东旺.安徽及邻区平均波速比的测定及研究[J].地震地磁观测与研究,2005,26(1):22-27.
[7]董治平,雷芳,申秀荣,等.西秦岭北缘断裂带的深部构造特征及其与地震活动的关系[J].内陆地震,1996,10(3):224-234.
[8]赵明淳,刁桂苓,张学民.首都圈平均波速比分析[J].西北地震学报,2005,27(3):246-254.
[9]蔡静观,张喜玲,李永莉.云南地区波速比异常图像的南北差异[J].西北地震学报,1999,21(4):363-369.
[10]梅世蓉,冯德益,张国民,等.中国地震预报概论[M].北京:地震出版社,1993:78-80.
[11]王德利,雍运动,韩立国,等.三维粘弹性介质地震波场有限差分并行模拟[J].西北地震学报,2007,29(1):30-34.
[12]粟生平,傅征祥.华北地区地震带分段波速比平均值的测定[J].地震,1996,16(2):114-120.
[13]秦保燕,张元生.波速比异常空间演化与主震位置预测[J].西北地震学报,2000,22(1):5-9.
[14]张学民,刁桂苓,束沛镒,等.华北地区地下介质波速比值(VP/VS)研究[J].地震地质,2004,26(2).305-317.
[15]李光泉,李伟东,施行觉,等.流体分布对松散介质中P波速度和衰减的影响[J].西北地震学报,2000,22(4):361-367
[16]荣棉水,李小军,卢滔.局部地形对入射P波谱特性的影响分析[J].西北地震学报,2007,29(4):297-302.
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