SEISMIC FIRST BREAK PICKING ALGORITHM WITH CASE STUDIES FOR FULL WAVE ELASTIC PHYSICAL MODELING IN THE LAB

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2012-05

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Abstract

This thesis presents several experiments of physical modeling in the Allied Geophysical Lab (AGL) at the University of Houston. The purpose of our physical models is to simulate the shallow water seismic acquisition using aluminum to represent a hard seafloor. The calibration of the model requires characterization of our particular aluminum, so several experiments were conducted to estimate its P-wave and S-wave velocity. The experiments cover a range of frequencies from 100 kHz to 5 MHz, allowing me to analyze the relation between velocity and frequency (velocity dispersion). In these measurements, travel time picking is critical for estimating the velocity accurately. Therefore, a fast and reliable picking algorithm was developed (named suaglpickr) and implemented in the C programming language as a program in the Seismic Unix (SU) processing package. The new picking program was validated and proved to be accurate and reliable. Picking details are made flexible through user inputs for choices of threshold level, or noise and signal window extent. The user can also adjust parameters to fine-tune the probability of false positive picks, for example, to control event-picking reliability. The picking algorithm is applied to seismic data from laboratory experiments to estimate seismic velocity in aluminum.

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Keywords

Picking algorithm, Seismic velocity, Full waveform, Seismic modeling

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