Seismic acceleration signal analysis and application

Abstract

Although various types of geophones are applied in seismic exploration, there are only three common types of signals produced by geophones: displacement, velocity, and acceleration signals. Currently, our understanding of the signal characteristics, such as the generation mechanism, the geophysical properties, and the significance of the corresponding rock physics, remains unclear, which makes it difficult to both scientifically evaluate and take full advantage of the different types of geophones. In this paper, the mechanism by which seismic waves are generated is studied based on the spring-damped vibration theory. The physical characteristics of the three above-mentioned signal types and the relationships among the physical properties of the signals and medium are analyzed, as well as the signal-to-noise ratio (SNR), resolution, and spectrum characteristics. Based on laboratory tests, field experiments, and applications, we obtained the following conclusions. The acceleration signal reflects the elastic characteristics of the medium and the change rules, and the signal strength is positively correlated with physical property changes. The acceleration signal has favorable attributes, such as small distortion, high fidelity, strong high-frequency amplitudes, and a wide frequency band. Therefore, the acceleration signal is more suitable for high-precision seismic exploration of complex media. In addition, the P-wave acceleration signal more accurately reflects the elastic Young modulus, shear modulus, and density changes than the velocity signal. However, the sensitivity decreases with increasing shear modulus and density. For the S-wave, the acceleration signal is more sensitive to the shear modulus and density than the velocity signal.