Variability of Seismic Radiation of Repeating Events as a Clue for Understanding Intermediate-Depth Earthquake Rupture

Session: What Can We Infer About the Earthquake Source Through Analyses of Strong Ground Motion? [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

How do earthquakes start? In particular, does the beginning of the rupture process of small and large earthquakes differ in some way? Today, the deterministic nature of rupture onset is still under debate but has strong implications on early warning systems. We use high-quality records of repeating intermediate-depth earthquakes in the Bucaramanga Nest, one of the most productive regions in the world. From 2010 to 2018 we have more than 160 M4+ earthquakes, many of them having very similar waveforms that we can assign to repeating families. After cross-correlation alignment, relocation and clustering of the seismic waveforms of these repeating events, we qualitatively try to determine what features are useful to determine the eventual size of the events based upon the variation of the rupture parameters as we propose. Given the high similarity between the frequency patterns and the differences in amplitude of the repeating earthquakes with significant differences in magnitude in the Bucaramanga Nest, we conclude that the temporal evolution of seismic radiation may show how and when one repeating event starts to grow larger than its family. Based on the information found in the first few seconds of the waveforms we infer the relationship between the slip amount and the area of the patches that are generating the repeating events. We see that this behavior of an increasing amount of slip within a constant patch area modeled numerically can be considered as a universal rupture pattern to all families in our catalog of intermediate-depth earthquakes.

Presenting Author: Sofia Cubillos

Authors