Characterization of seismic signals and background seismic noise

Abstract

A variety of signal processing methodologies have been utilized in the analysis and characterization of the seismic signals and the background noise recorded by modern seismic instrumentation at the UC Berkeley Seismological Laboratory. The capabilities of seismic instrumentation have vastly improved over the past couple of decades since the advent of microcomputer and related technologies. Modern seismic instrumentation consists primarily of force fedback broadband seismometers (to record weak ground motions) and strong motion accelerometers (to record large local shocks) coupled to high resolution digital (24-bit+integer) data loggers. We discuss the characteristics and capabilities of the various seismic sensors and the digital recording systems. The earth’s background noise and the instrumental self-noise characteristics are discussed. Various weak signals (both coherent and transient) detection and analysis methodologies are also discussed along with some interesting cases of detecting and characterizing unusual natural and artificial seismic sources.