南北地震带北段上地幔速度结构成像(Ⅰ)——方法与原理

IMAGING OF VELOCITY STRUCTURE OF THE UPPER MANTLE FOR THE NORTHERN PORTION OF NORTH-SOUTH SEISMIC BELT (Ⅰ)-THEORY AND METHOD

摘要:

本文详细讨论了利用P_n波走时资料对莫霍面的慢度场层析成像的方法与原理。在地震波慢度场的非均匀分布相对背景场为一挠动量的情况下,其走时为背景场分量与挠动场分量的线性迭加,因此,从观测走时中可提取出相对背景场的异常量。对走时异常分量的表达式作适当的变换即可得出拉冬变换形式,运用反投影重建或拉冬逆变换,可以直接求出慢度场的分布。

Abstract:

This paper deals with the theory and method of tomographic imaging of slowness field at the Moho surface using the data of the Pn wave travelling time.In the case of slowness inhomogeneous distribution which is disturbance compared with the background,the travelling time is a linear superposition of the background,and disturbance component,and the later can be extracted from the observation.Applying.the suitable transform on the formula of the disturbance component,the form of Radon transform is obtained.Then based on the inverse projection reconstruction or inverse Radon transform,the slowness distribution can be deduced directly.