闽粤地区同震形变波记录序列分析及小波能谱特征

基于闽粤地区10个地形变观测点40个测项的同震形变波记录,利用幅度比值和小波多尺度分析方法探讨其记录特点和传导机制,结果显示:1)同震形变波到时与震中距有关,波形记录含有d-P和d-S波,不同测项记录到的波形不一致,同测项的记录波形相似;2)幅度比值在一定程度上与震源方位有关,进一步反映其各向异性;3)通过互(自)相关计算和滤波处理,能识别出同震形变波的频带为0.02~0.04 Hz,峰值在0.025Hz附近;4)智利地震形变波序列小波能谱为64~254s,能量集中在128~254s;而尼泊尔地震形变波在不同测点区别较大,潮州台为16~32s,厦门台为16~64s。研究结果表明,形变记录中除面波外还包含体波成分,不同震源机制引起的同震形变波传导机制可能存在各向异性,这对于开展地震引发应变等研究有借鉴意义。

Sequence Analyses and Wavelet Spectrum Characters of Co-Seismic Deformation Wave Record in Fujian-Guangdong Area

This paper uses sequence analysis and wavelet spectrum methods to discuss co-seismic deformation waves (CSDW) records characters and its conduct mechanism in Fujian-Guangdong area.The deformation data, based on 10 stations, includes 40 precursory anomalies in total. The result show that: (1) Arrival-time of CSDW is related to epicentral distance, the records include d-P and d-S waves, the records from different items are not consistent, and the same measured items are similar to the recorded waveform. (2) To a certain extent, the amplitude ratio shows the direction of the source, and further reflects the direction anisotropy of the amplitude ratio. (3) By calculating the cross(self)-correlation and filter processing, we can identify the CSDW bands in 0.02~0.04 Hz; the peak value is about 0.025Hz. (4) The wavelet spectrum band of Chile earthquake CSDW is mainly 64~254 s, the main energy is concentrated in 128~254 s, which is different thanthe Nepal earthquake CSDW. Different measuring points are different, the band of Chaozhou and Xiamen station is 16~32 s and 16~64 s, respectively. Results suggest the CSDW records include P wave and S wave elements except surface waves; in addition, the conduction mechanism of CSDW, which is caused by different focal mechanisms, may be anisotropic.This study has reference significance for the study of earthquake induced strain.