华南地震
華南地震
화남지진
SOUTH CHINA JOURNAL OF SEISMOLOGY
2014年
3期
24-32
,共9页
近断层地震动%小波方法%速度脉冲%统计特性
近斷層地震動%小波方法%速度脈遲%統計特性
근단층지진동%소파방법%속도맥충%통계특성
Near fault ground motion%Velocity pulse period%Peak ground velocity%Wavelet approach%Site effect
采用小波方法筛选出了180条断层距在20 km之内且PGV大于10 cm/s的具有速度脉冲特征的近断层地震波,分别对基岩和土层场地、走滑(SS)和非走滑(NSS)断层、不同脉冲峰值标准情形下近断层脉冲周期和矩震级的关系进行了统计,得到了不同情形下脉冲周期-震级经验公式回归系数,以供近场地震动速度脉冲的相关研究参考使用。结果表明:走滑断层产生的脉冲周期比非走滑断层的大,但随震级的增大情况发生变化;无论走滑断层还是非走滑断层,当震级较小时,土层场地的脉冲周期比基岩场地的大,随着震级的增加,基岩场地的脉冲周期将比土层场地的大;根据不同标准的速度脉冲峰值PGV记录,得到的周期-震级关系曲线有很大区别。
採用小波方法篩選齣瞭180條斷層距在20 km之內且PGV大于10 cm/s的具有速度脈遲特徵的近斷層地震波,分彆對基巖和土層場地、走滑(SS)和非走滑(NSS)斷層、不同脈遲峰值標準情形下近斷層脈遲週期和矩震級的關繫進行瞭統計,得到瞭不同情形下脈遲週期-震級經驗公式迴歸繫數,以供近場地震動速度脈遲的相關研究參攷使用。結果錶明:走滑斷層產生的脈遲週期比非走滑斷層的大,但隨震級的增大情況髮生變化;無論走滑斷層還是非走滑斷層,噹震級較小時,土層場地的脈遲週期比基巖場地的大,隨著震級的增加,基巖場地的脈遲週期將比土層場地的大;根據不同標準的速度脈遲峰值PGV記錄,得到的週期-震級關繫麯線有很大區彆。
채용소파방법사선출료180조단층거재20 km지내차PGV대우10 cm/s적구유속도맥충특정적근단층지진파,분별대기암화토층장지、주활(SS)화비주활(NSS)단층、불동맥충봉치표준정형하근단층맥충주기화구진급적관계진행료통계,득도료불동정형하맥충주기-진급경험공식회귀계수,이공근장지진동속도맥충적상관연구삼고사용。결과표명:주활단층산생적맥충주기비비주활단층적대,단수진급적증대정황발생변화;무론주활단층환시비주활단층,당진급교소시,토층장지적맥충주기비기암장지적대,수착진급적증가,기암장지적맥충주기장비토층장지적대;근거불동표준적속도맥충봉치PGV기록,득도적주기-진급관계곡선유흔대구별。
In this paper, 180 records are selected based on wavelet approach. These records show three common features:their rupture distances are less than 20km, their peak ground velocity (PGV) are greater than 10cm/sec and they all show characteristics of velocity pulses for near-fault strong motions. All Records are divided into groups according to different site conditions (rock vs. soil), different fault types (strike-slip fault vs. non-strike-slip fault) and different PGV threshold levels. Regression coefficients of several period-magnitude relationships in different situations are then given. With statistics in hand, several conclusions can be made: ① pulse periods in strike-slip faults are greater than those in non-strike-slip faults, but things changed with moment magnitude greater than 7, which is believed to have relationship with insufficient severe earthquake records. With limited severe earthquake records, the result may be affected. ② In both strike-slip faultsˊ and non-strike-slip faultsˊ cases, pulse periods in rock sites are greater than those in soil sites with moment magnitude less than 6.5 or so, and pulse periods in rock sites will be greater than those in soil sites as moment magnitude increases, but the boundary line on which pulse periods change differs according to different fault types. ③ The period-magnitude relationships derived from different PGV threshold levels varies a lot. For non-strike-slip faults, both soil sites and rock sites show the same property, that is, when magnitude is relatively small, the higher the PGV threshold level is, the smaller the pulse periods will be, however, pulse periods increase with the moment magnitude, when the moment magnitude reaches a certain degree, pulse periods from lower PGV threshold levels will be greater than those from higher ones. However, for non-strike-slip faults, in soil sitesˊ cases, it is just the other way around, while in rock sitesˊ cases, such trend is not obvious, which may be caused by limited data volume.