河套地震带分区地震空间相关长度变化特征

Correlation length spatial distribution characteristics in Hetao seismic zone

以河套地震带作为研究区域,选取2001年以来小震事件作为研究对象,采用单键群(SLC)方法,计算研究区地震空间相关长度,并分区域讨论其时序变化特征。计算结果表明,2001年以来,河套地震带5个子区域地震空间相关长度表现出不同变化特征,且无持续性变化,多在约3年时间尺度上表现出增长现象,表明地震空间相关长度的增长变化不太可能反映区域应力场的长期变化,而可能携带应力场的中期变化信息。通过设定不同计算窗长和滑动步长来考证计算结果,发现地震事件时空分布的非均匀性、空间窗形状和大小等因素,可能影响地震空间相关长度的数据变化幅度,但不影响整体变化趋势。

Take the Hetao seismic zone as the study area, selected small earthquake events since 2001, using the SLC method to calculate the seismic spatial correlation length, temporal variation characteristics of correlation length was discussed. Results show that since 2001, correlation length showed different spatial characteristics in 5 sub regional, and the correlation length of each sub region did not show a continuous change. In 3 years time scale, correlation length growth showed growth phenomenon and showing that the correlation length growth spatial change is unlikely to reflect the regional long-term change the force field, and is likely to carry the mid change information of stress field. By setting different calculation window length and sliding step to verify the calculation results reveal the space-time distribution of seismic events, we know that the factors such as heterogeneity, shape and size of the spatial window may influence the magnitude of the spatial correlation length, but do not affect the overall trend