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2012年7月20日20时11分在江苏高邮与宝应交界发生了M4.9级地震,是江苏地区陆地上近22年来的最大地震.本文是运用频率-波速(F-K)方法,来模拟得到深度震相sPL在不同深度模型下的理论地震图,然后在径向(R)、切向(T)和垂直向(Z)上与实际观测波形进行拟合比较,来最终确定出震源深度.根据sPL震相的优势震中距范围30~50 km,从江苏省数字地震台网中,筛选出波形记录质量信噪比高的宝应台(BY)、盐城台(YC)来进行计算,计算结果显示:宝应台和盐城台在震源深度模型分别为11 km和10 km时,理论地震图和实际观测波形的拟合结果最为接近.这一结果与利用结合波形互相关的双差定位法获得的震源深度,约10.2 km基本一致,初步表明在覆盖层厚的江苏中部地区,利用sPL震相来测定震源深度是可靠的.
At 20:20 on July 20, 2012 at the junction of Gaoyou and Baoying in Jiangsu Province, a M4.9 earthquake hit the area of Jiangsu in the recent 22 years, the largest earthquake in this paper is the use of frequency - wave velocity (FK) method to simulate The theoretical seismograms of deep phase sPL under different depth models are then compared with the observed waveforms in the radial (R), tangential (T) and vertical (Z) directions to determine the focal depth. According to the superior epicenter range of sPL seismic facies, 30-50 km, we selected from the digital seismic network of Jiangsu Province the data of BY and YC with high signal-to-noise ratio of waveform recording quality, and calculated the results The results show that the fitting results between the theoretical seismograms and the actual observed waveforms are the closest when the focal depth models are 11 km and 10 km, respectively, and this result is in good agreement with that obtained by using the double-difference localization method The depth of the focal point is about 10.2 km, which basically indicates that it is reliable to use the sPL seismic facies to determine focal depth in the central part of Jiangsu with thick overburden.