分离三分量远震接收函数的多道最大或然性反褶积方法

MULTI-CHANNEL MAXIMAL LIKELIHOOD DECONVOLUTION METHOD FOR ISOLATING 3-COMPONENT TELESEISMIC RECEIVER FUNCTION

迄今为止 ,广泛应用的分离接收函数方法主要基于单个台站的观测数据 ,并依赖等效震源假定的有效性。当地壳内存在明显的间断面时 ,等效震源假定不适于宽频带地震波形数据 ,接收函数的估计将在不同程度上遭到破坏。解决这个问题的出路在于避免使用等效震源假定。依据多道最大或然性反褶积原理 ,给出了利用多道观测数据分离接收函数的方法。我们的方法避免了等效震源假定 ,这对于在复杂构造环境条件下改善接收函数的估计具有实际价值。合成地震图的数值检验结果验证了给出的方法。利用该方法 ,我们得到了跨越大别山造山带 ,从江西大冶附近的大箕铺 (30°2 0′N ,1 1 5°0 3′E)到河南兰考附近的崔林 (34°4 0′N ,1 1 4°4 9′E) ,总长度约 5 0 0km的流动地震台阵剖面各台站的三分量接收函数估计。与基于单台数据的接收函数径向分量比较表明 。

Up to now, all of the methods of isolating the receiver function from teleseismic P waves are based on the data recorded at a single station. However, the estimation of the receiver function based on the so called source equalization scheme will not be valid for broadband data, when a sharp discontinuity exists within the crust. The outlet for solving this problem is to avoid using the source equalization assumption. In this study, we propose a method for isolating the 3 component receiver function from multi channel seismic data based on multi channel maximal likelihood deconvolution princple. The source equalization scheme is avoided in our method, and this is valuable for improving the estimation of the receiver function in case of complex crustal structure. The numerical test by synthetics proves our method to be effective. Using this new method, we obtain the 3 component receiver functions at stations along the passive seismic profile across the Dabieshan orogenic belt from Daqipu (30°20′N,115°03′E) nearby Daye, Jiangxi Province to Cuilin(34°40′N,114°49′E)nearby Lankao, Henan Province. In comparison with the radial components of the receiver function from the data of a single station, it is indicated that the results given by both methods have un negligible differences.