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Introduction

My Least-Squares Joint Imaging of Multiples and Primaries (LSJIMP) algorithm Brown (2003a) separates pegleg multiples and primaries. LSJIMP computes separate images of the peglegs and primaries, and then uses the mutual consistency of the images to discriminate against unwanted noise types in each image. The images must be consistent in two respects. Kinematically, the events must be correctly positioned in time and flat with offset. This is accomplished by an improved normal moveout operator (HEMNO) introduced in a companion paper in this report Brown (2003b). This paper addresses the second aspect of image consistency: amplitudes.

LSJIMP requires that the amplitudes of the pegleg images be correct not in absolute terms, but relative to the primary image. Correct modeling of the relative amplitudes of pegleg multiples requires more work than a scaling by a reflection coefficient. For one, the reflection coefficient of the multiple-generating layer generally varies with position. Multiples also have longer raypaths through the earth, and thus suffer greater geometric spreading and anelastic attenuation losses than do primaries with the same offset. Furthermore, multiples and primaries have different reflection angles for a fixed offset, so the multiples and primaries will exhibit different amplitude-versus-offset (AVO) behavior.

In this paper, I present three innovations which transform pegleg multiples into events which are directly comparable to their corresponding primary reflections.


next up previous print clean
Next: Snell Resampling Removes AVO/Attenuation Up: Brown: Pegleg amplitudes Previous: Brown: Pegleg amplitudes
Stanford Exploration Project
7/8/2003