Seismic Phase Association Based on the Maximum Likelihood Method

• Published in: Frontiers in earth science (Lausanne) Vol. 9
• Main Authors: Sheen, Dong-Hoon, Friberg, Paul A.
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 25-08-2021
• Subjects: earthquake early warning system; earthquake monitoring system; earthworm; local earthquake; maximum likelihood method; seismic phase association
• ISSN: 2296-6463; 2296-6463
• DOI: 10.3389/feart.2021.699281

Phase association is a process that links seismic phases triggered at the stations of a seismic network to declare the occurrence of earthquakes. During phase association, a set of phases from different stations is examined to determine the common origin of phases within a specific region, predominantly on the basis of a grid search and the sum of observations. The association of seismic phases in local earthquake monitoring systems or earthquake early warning systems is often disturbed not only by transient noises, but also by large regional or teleseismic events. To mitigate this disturbance, we developed a seismic phase association method,
binder_max
, which uses the maximum likelihood method to associate seismic phases. The method is based on the framework of
binder_ew
, the phase associator of Earthworm, but it uses a likelihood distribution of the arrival information instead of stacking arrival information. Applying
binder_max
to data from seismic networks of South Korea and Ohio, United States, we found a significant improvement in the robustness of the method against large regional or teleseismic events compared to
binder_ew
. Our results indicate that
binder_max
can associate seismic phases of local earthquakes to the same degree as
binder_ew
as well as can avoid many of the false associations that have limited
binder_ew
.