地震研究

利用云鹏水电站周边5个数字地震台站记录到的2000年1月至2008年12月间的108个地震的数字波形资料,采用Aki单次散射模型,计算了各台站周围423条地震记录的尾波Q₀值。结果显示:云鹏水电站地区尾波的Q_c值与频率的关系为Q_c(f)=90.2f ^0.94。该地区的Q₀值比云南其它构造活动强烈地区的要高,因此属于中等构造活动地区。云鹏水电站蓄水后弥勒台记录到的108个地震的尾波Q₀值及分频Q_c值有所下降,但下降幅度不大,表明水库蓄水对库区及其附近区域地下介质性质有所影响,但影响的程度有限。

The coda-wave-attenuation-quality factor Q₀ in Yunpeng Hydropower Station area and its adjacent regions is estimated using Aki's single-scattering attenuation model based on 108 local seismic events recorded by 5 regional digital seismic stations from January 2000 to December 2008.The result shows that the relationship between Q₀ and f can be described as Q_c(f)=90.2f ^0.94.Compared with the ones in other areas of Yunnan with strong tectonic seismic activity,the values are higher in this area with moderate tectonic activity.The Q₀ and Q_c values declined a little after the Yunpeng reservoir impounded water; this means that the water storage has influenced the medea character in this area,but the effect is limited.

引言
1 计算方法
2 地震资料及分析处理
4 结论与讨论

图1 2007年丘北—泸西小震群震中、台站、断裂、云鹏水电站位置分布图(a)及本研究所用地震M-T图(b)<br/>Fig.1 Distribution of epicenters、stations、faults and Yunpeng Hydropower Station (a)and the M-T diagram of the selected earthquakes(b)

图1 2007年丘北—泸西小震群震中、台站、断裂、云鹏水电站位置分布图(a)及本研究所用地震M-T图(b)
Fig.1 Distribution of epicenters、stations、faults and Yunpeng Hydropower Station (a)and the M-T diagram of the selected earthquakes(b)

表1 震群周边数字地震台主要参数<br/>Tab.1 Main parameters of the digital seismic stations around the earthquakes

表1 震群周边数字地震台主要参数
Tab.1 Main parameters of the digital seismic stations around the earthquakes

图2 丘北ML3.0地震原始波形及滤波后各中心频率的波形图<br/>Fig.2 Primary waveform of Qiubei ML3.0 earthquake and the waveform at different central frequency pots after filtered

图2 丘北ML3.0地震原始波形及滤波后各中心频率的波形图
Fig.2 Primary waveform of Qiubei ML3.0 earthquake and the waveform at different central frequency pots after filtered

图3 中心频率为10 Hz的ln[Ac(f,t)*t)]与<br/>t的数据点及回归线(a)和地震尾波Qc值拟合结果(b)<br/>Fig.3 Pots and tropic between ln[Ac(f,t)*t)] and t when centre frequency is 10 Hz(a) and the sketch map of the relationship between Qc value and frequency(b)

图3 中心频率为10 Hz的ln[Ac(f,t)*t)]与
t的数据点及回归线(a)和地震尾波Qc值拟合结果(b)
Fig.3 Pots and tropic between ln[Ac(f,t)*t)] and t when centre frequency is 10 Hz(a) and the sketch map of the relationship between Qc value and frequency(b)

图4 弥勒地震台记录的108个地震不同中心频率尾波Qc值<br/>Fig.4 Qc value of 66 earthquakes recorded by Mile digital seismic station at different centre frequency pots

图4 弥勒地震台记录的108个地震不同中心频率尾波Qc值
Fig.4 Qc value of 66 earthquakes recorded by Mile digital seismic station at different centre frequency pots

图5 不同台站记录的地震尾波Qc值及其与频率的关系<br/>Fig.5 Relation between Qc value and frequency recorded by different digital seismic stations

图5 不同台站记录的地震尾波Qc值及其与频率的关系
Fig.5 Relation between Qc value and frequency recorded by different digital seismic stations

表2 云鹏水电站及其附近区域尾波Qc值计算结果<br/>Tab.2 Results of value of Qc coda wave around Yunpeng Hydropower Station

表2 云鹏水电站及其附近区域尾波Qc值计算结果
Tab.2 Results of value of Qc coda wave around Yunpeng Hydropower Station

图6 不同地区的尾波Q-1c随频率的变化特征<br/>Fig.6 Change characteristic of the Q-1c value and frequency among different areas

图6 不同地区的尾波Q-1c随频率的变化特征
Fig.6 Change characteristic of the Q-1c value and frequency among different areas

图7 弥勒台记录到的地震尾波Q0值随时间变化趋势图(a)蓄水前;(b)蓄水后<br/>Fig.7 Coda Q0 value variation with time recorded by Mile digital seismic station (a)before the water storage; (b)after the water storage

图7 弥勒台记录到的地震尾波Q0值随时间变化趋势图(a)蓄水前;(b)蓄水后
Fig.7 Coda Q0 value variation with time recorded by Mile digital seismic station (a)before the water storage; (b)after the water storage

表3 弥勒台地震尾波Qc值蓄水前后变化特征<br/>Tab.3 Change of Coda Qc value recorded by Mile digital seismic station before and after impound water

表3 弥勒台地震尾波Qc值蓄水前后变化特征
Tab.3 Change of Coda Qc value recorded by Mile digital seismic station before and after impound water

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备注

引言

1 计算方法

2 地震资料及分析处理

4 结论与讨论

期刊信息