An earthquake detection, identification, and location system for the northeastern U.S. Based on the wavelet transform

Abstract

In order to optimize the ability of the New England Seismic Network (NESN) to detect all local earthquakes to the smallest possible magnitude, Weston Observatory of Boston College has developed an automated event detection and identification system based on the wavelet transform. This software system performs a wavelet transform on the data from each station being received and uses the time, frequency content, and energy of the first arrival, the highest energy arrival, and the end of the detection to compute the Bayesian probability that the detection was a distant earthquake (teleseism), regional earthquake, local earthquake, quarry blast, Rg wave from a quarry blast, or transient noise. At each station, these measured parameters are used to estimate the origin time, epicentral distance, and magnitude for each detection. The systems attempts to associate the detections from different stations that have a common event identification as a teleseism, regional/local earthquake, or quarry blast. If three or more stations associate, an automatic event location and magnitude (if a regional or local earthquake) are computed. This wavelet-transform detector and identifier has greatly increased the sensitivity of detecting and locating small earthquakes and quarry blasts in the New England region.