不同分裂强度计算方法的各向异性成像对比研究:以川滇地区为例OA

Seismic tomography provides a fundamental approach for probing the internal structure of the Earth.In recent years,imaging methods based on shear-wave splitting intensity(SI)have steadily advanced,enhancing investigations into upper-mantle anisotropy.In practice,SI is measured by projecting the transverse component of a shear wave onto the time derivative of the radial component.Under low-frequency conditions and for small delay-time conditions(ωδt ≪ 1 or ωδt → 0),SI follows a sinusoidal relationship with the splitting parameters,φ and δt.By retaining the complete mathematical expressions of the radial and transverse components and substituting them into the projection-based integral definition,a new relationship incorporating the dominant angular frequency,ω,can be derived.While,current anisotropic imaging studies generally adopt waveform-derived SI as the observational constraint,the imaging performance of SI calculated from pre-estimated splitting parameters remains poorly understood.Focusing on the Sichuan-Yunnan region,this study systematically compares anisotropic imaging results obtained from three types of SI:waveform-measured SI,SI calculated using the conventional sinusoidal relation,and SI derived from the new frequency-dependent formulation.The results demonstrate that,compared with the conventional sinusoidal formulation,imaging based on the new relationship yields structures that are more consistent with those obtained from waveform-derived SI,indicating its improved reliability for anisotropic tomography.