SUBSURFACE INVESTIGATION USING REFRACTION MICROTREMOR

Abstract

Refraction Microtremor method is a class of non invasive method with a passive source which uses ambient seismic noise to gather data along an array of geophones to predict the velocity model of the subsurface. This method was developed by John N. Louie in 2001 and based on the premise that simple geophones arranged in an array using passive source is able to receive very low frequency waves and that a 2D slowness-frequency (p-f) transform can separate Rayleigh waves from kinds of waves. The advantages of this method over other methods are that it is very fast and not very expensive, the tool and instruments required are readily available, it is not affected by sources of noise and can be used discreetly without an active source. But studying ReMi data is without the use of commercial software is tough as the data is kept secret using proprietary file standards and other licences. In this study, I present to you a computer program written in Python 3 which is able to generate a synthetic seismic traces similar to actual ReMi acquisition data and a separate program which is able to convert initial data in the form of amplitudes relative to distance and time ( A(x,t) ) and convert it to slowness-frequency (p-f) domain which can later be used derive subsurface velocity properties using various forward modeling and inversion methods.