Body-to-surface-wave scattered energy in teleseismic coda observed at the NORESS seismic array
Body-to-surface-wave scattered energy in teleseismic coda observed at the NORESS seismic array
复制标题
在 NORESS 地震台阵观测到的远震尾波中的体面波散射能量
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
C. Langston
中科院分区：
文献类型：
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作者：
Gregory S. Wagner;C. Langston
摘要对NORESS地震台阵记录的远震数据进行了检查，以确定台阵下方岩石圈非均质性的程度和规模，并确定局部散射源的位置。使用相对尾波强度包络、频率-波数谱和粒子运动极化来检验数据。尾波强度包络没有表现出任何明显的ka趋势；然而，0.5hz通带数据确实包含更高的能级和在第一次到达15秒后的高能包∼。频率波数分析表明，大部分远震尾波是垂直传播的。然而，以15秒为中心的窗口包含了以低视速度向东北方向移动的能量。此窗口中的粒子运动遵循瑞利表面波的逆行椭圆模式。据推测，对观测到的体表波散射能量负责的散射源是位于阵列西南偏西约30公里处的Mjosa湖。
Abstract Teleseismic data recorded at the NORESS seismic array are examined to determine the degree and scale of lithospheric heterogeneities beneath the array and to locate local scattering sources. The data are examined using relative coda intensity envelopes, frequency-wavenumber spectra, and particle motion polarizations. The coda intensity envelopes do not exhibit any clear ka trends; the 0.5-Hz pass-band data does, however, contain higher energy levels and a high energy packet ∼ 15 sec after the first arrival. Frequency-wavenumber analysis shows shows that most of the teleseismic coda is vertically propagating. The window centered near 15 sec, however, contains energy traveling to the northeast at a low apparent velocity. Particle motions in this window follow a retrograde elliptical pattern characteristic of Rayleigh surface waves. The scattering source presumed to be responsible for the observed body-to-surface-wave scattered energy is Lake Mjosa located approximately 30 km west-southwest of the array.