【摘要】 传统的走时层析反演都是依赖于射线理论,而实际地震资料的带限特征与射线理论无限高频的假设存在理论上的矛盾.针对传统的射线层析存在的上述问题,本文从频率域波动方程的Born和Rytov近似入手,推导出菲涅尔带走时层析敏感核函数,其与传统的射线层析方法的显著区别在于它建立在带限地震波与第一菲涅尔带的理论基础上.通过射线走时残差与Rytov近似走时残差的比较,本文提出了依据Rytov近似走时残差的菲涅尔层析反演方法.表层速度模型试算结果表明,相对于传统的射线走时层析,基于频率域波动方程的菲涅尔带走时层析成像方法具有更高的成像精度与分辨率.更多还原

【Abstract】 In the traditional seismic imaging experiments,ray theory plays an important role in gaining the velocity construction.In reality,recorded wave signal is band-limited which is contradictive with the infinite-frequency assumption.We start from the Born and Rytov approximation of frequencydomain wave equation to derive the traveltime sensitivity kernels for Fresnel zone tomography.It is distinguished from the ray theory in that the sensitivity is established on the bandlimited wave signal and the first Fresnel zone. We present Fresnel zone tomography based on the Rytov approximation traveltime delay by comparing it with ray theory traveltime delay.We apply our method into the construction of the near surface velocity model.The inverted result proves that our method has a higher resolution and accuracy when comparing with the ray theory tomography.更多还原