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对加拿大东部遥测台网(ECTN)1980年至1990年问记录到的 S 波波列的垂直分量进行了用于震源、场地及传播特征研究的频谱分析.该组数据包括记录到的97次地震的1033个记录,其震级范围在 M≈3～6之间,震中距为15～1000km,大部分记录是在200～800km 之间获得的;记录到的 S 波波列包含 S,S,S,S和 L_9震相,取样窗长随距离增大;分析了从1.0～10 Hz 的加速度频谱。为区分出震源、场地和传播特征,交替使用了一种关于地震拐角频率、低频水平及平均衰减参数的反演和将残差回归到上述台站上和一种基于台站组及距离介于25～1000km之间的14种距离的网格上的方法。在大约60步之内,这两部分反演之间的迭代收敛。从反演获得的平均衰减参数为:Q=1997±10,γ=0.998±0.003。该平均衰减的最显著变化是在63 km 和2 Hz 上存在大于2倍的明显衰减,它随频率增加及距离增大到200 km以外而变得不明显。从加拿大东部遥测台站获得的场地响应谱一般是扁平的,反演中设定的谱形态为该数据组中布伦应力降范围在5～150bar之间的较小事件(M_0<3×10~(21) dyne—cm)提供了一种适当的频谱模式。但是,对于数据组中 M_0≥10~(23) dyne—cm 的五个事件来说,通过残差回归得到的震源频谱表明,ω~2谱是一种不适合的频谱模式。特别是对于多数大事件,其拐角频率出现分裂,致使频谱显现一种居间的状态(这里|u(ω)|与ω大约成正比)。
Spectral analysis of the vertical component of S-wavelets recorded by ECTN from 1980 to 1990 for the study of source, site and propagation characteristics was performed and included 97 recorded earthquakes Of the 1033 records, the magnitude range of M ≈ 3 ~ 6, the epicentral distance of 15 ~ 1000km, most of the records are obtained between 200 ~ 800km; recorded S wave train contains S, S, S , S and L_9 phases, and the sampling window length increases with distance. The acceleration spectrum from 1.0 to 10 Hz is analyzed. In order to distinguish the source, the site and the propagation characteristics, an inversion of the seismic corner frequency, low frequency level and average attenuation parameters is used alternately and the residuals are returned to the above stations and a station-based and distance- A method on a grid of 14 distances between 25 and 1000 km. Within about 60 steps, the iteration between these two partial inversions converges. The average attenuation parameters obtained from inversion are: Q = 1997 ± 10, γ = 0.998 ± 0.003. The most significant change in this mean attenuation is a significant attenuation greater than 2 times at 63 km and 2 Hz, which becomes insignificant as the frequency increases and the distance increases beyond 200 km. The site response spectrum obtained from telemetry stations in eastern Canada is generally flat, and the spectral shape set in the inversion is a small event with a Buren stress drop in the range of 5-150 bar (M_0 <3 × 10 ~ (21) dyne-cm) provides a suitable spectral pattern. However, for the five events with M_0≥10 ~ (23) dyne-cm in the data set, the source spectrum obtained by residual regression shows that the ω ~ 2 spectrum is an unsuitable spectral mode. Especially for most major events, the corner frequency splits, resulting in an intermediate spectrum (here | u (ω) | approximately proportional to ω).