← Back to Sessions

Improved Characterization of Earthquake Sequence Patterns in the Mexican Subduction Zone Using Seismogram Correlation to Enhance Detection of Smaller Seismicity

Description: 

In the past decade, there has been a staggering ten magnitude 7 or larger earthquakes in Mexico, while detailed studies have identified earthquake swarms are also prominent in this region. Ventura-Valentin et al. (2024) generated a catalog of 667 sequences with at least 10 clustered earthquakes in the 2012-2022 Mexico SSN catalog using the approach of Zaliapin & Ben-Zion (2013). They developed an automated characterization of these sequences to help distinguish which are mainshock-aftershocks and which are swarms. However, nearly half of the sequences have less than 15 events, making it difficult to understand their behavior. To investigate whether undetected smaller events could enhance our understanding of these sequences, we sought to apply the template-matching form of seismogram correlation to improve the detection of events in each sequence. We developed an efficient strategy for determining the cross-correlation threshold for positive detections at a single station based on statistical deviation from the background rate of detection for spurious noise.
Of the 100 sequences we focused on, template matching produced a change in characterization type for approximately half of the sequences (change greater than 0.3 units on the automated rating scale). We then explored template matching of the sequences over the full 10 years which revealed 3 general temporal patterns of seismic activity associated with the patches of fault the sequence represents. Approximately two-thirds of the sequences showed evidence for episodic activity over the longer time frame, with other sequences showing activity that was either isolated to the time frame of the original sequence or ongoing activity every month of the 10 years. However, we also identified that some sequences match with each other, indicating spatial proximity and potential relationships that make sequence characterization more complicated. To address this, we explored the relative influence of swarm-like behavior, similarity with nearby sequences, and distance from the station on the overall productivity of the template matching.

Session: Advanced Geophysical Observations, Analytical Methods, and New Insights for Earthquake Swarms [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Mehrnaz

Student Presenter: Yes

Invited Presentation: 

Poster Number: 113

Authors