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地震 ›› 2006, Vol. 26 ›› Issue (4): 15-21.

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江西九江-瑞昌震区的尾波衰减特征初探

吕坚1,2, 朱新运3, 高建华1, 沈小七4, 汤兰荣1, 肖建华1   

  1. 1.江西省地震局, 江西 南昌 330039;
    2.中国科学技术大学, 安徽 合肥 230026;
    3.浙江省地震局, 浙江 杭州 230031;
    4.安徽省地震局, 安徽 合肥 230031
  • 收稿日期:2006-04-11 修回日期:2006-07-05 发布日期:2021-11-01
  • 作者简介:吕坚(1975-), 男, 江西寻乌人, 2005年在读研究生, 主要从事地震预测和地震安全性评价等研究。
  • 基金资助:
    中国地震局监测预报司“九江-瑞昌地震数字化观测资料应用与研究”专项

Research on coda attenuation feature in Jiujiang-Ruichang seismic areas

LÜ Jian1,2, ZHU Xin-yun3, GAO Jian-hua1, SHEN Xiao-qi4, TANG Lan-rong1, XIAO Jian-hua1   

  1. 1. Earthquake Administration of Jiangxi province, Nanchang 330039;
    2. University of Science and Technology of China, Hefei 230026;
    3. Earthquake Administration of Zhejiang province, Hangzhou 310013;
    4. Earthquake Administration of Anhui province, Hefei 230031, China
  • Received:2006-04-11 Revised:2006-07-05 Published:2021-11-01

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摘要： 根据单次散射模型, 利用数字地震记录资料研究和讨论了江西省九江-瑞昌震区的尾波衰减特征, 获得了可信的结果。 经过计算, 震中距30 km内的5个地震台站得到Q0值在75～79内波动。 η值大体可以分为两类: 九江台和范镇台η值为0.86～0.88; 丁家山、 狮子洞和武皎台η值为0.94～0.97,这种差别可能与台站方位有一定的关系。 考虑到此次地震的破裂尺度不会太大, 可采用后3个台的计算结果, 拟合得到九江-瑞昌震区尾波Qc值随频率的变化关系为Qc(f)=(77.5±15.6)f0.96±0.09。 九江-瑞昌震区的Q0值为77.5, η值为0.96, 与云南武定、 施甸地区接近, 这种类似现象是构造运动活跃地区的特征体现还是反映了中强地震破裂区局部介质性质的一种共性, 有待于进一步深入研究。 本研究参与计算的5个台站最大尾波流逝时间为40～44 s, 得到的平均采样体深度约为53 km, 相对江西地区地壳平均厚度33 km而言, 结果反映的是九江-瑞昌震区地壳和上地幔顶部的介质性质。

关键词: 尾波Qc值, 九江-瑞昌震区, 介质性质

Abstract: Based on the single scatter model (Aki), value of coda was calculated in Jiujiang—Ruichang earthquake-stricken area in Jiangxi province, using digital seismic wave recorded by five stations whose epicenter distance was less than 30 km. The result shows the seismic coda attenuation feature in the relative region as follows: ① The value of varies form 70 to 79, based on value of η, the result showed two kinds of change, the η value, obtained from these wave data recorded in the Jiujiang and Fangzhen stations, varies from 0.86 to 0.88, the other value, obtained from the wave data recorded in the Dingjiashan, Shizidong and Wujiao stations, varies from 0.94 to 0.97. The deference among the value of η may correlated to the direction of stations which recorded these wave. Taking the size of the earthquake rupture into account, the mean coda attenuation coefficient in the area was obtained just using the wave data obtained from the late 3 stations, the result is Qc(f)=(77.5±15.6)f0.96±0.09. ② The result is in accordance with what obtained in Wuding Shidian area in Yunnan Province, the result may show that the geologic structure is identical in the two areas. In the study 40~44 s of elapsed time windows were used to calculate the attenuation coefficient, the corresponding sampling depth is about 53 km. The result shows the attenuation feature of the earth crust and the upper mantle in the area.

Key words: Value of coda, Jiujian-Ruichang earthquake-stricken area, Feature of medium

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