Aftershock Productivity Variation in Intermediate-Depth Earthquakes

Session: Earthquake Source Parameters: Theory, Observations and Interpretations
Type: Oral
Date: 4/30/2020
Time: 01:45 PM
Room: 120 + 130
Description: 

The mechanism(s) causing intermediate-depth, intraslab earthquakes are not well understood: dehydration-linked embrittlement and thermal shear runaway are among the more well-supported proposed mechanisms for these events, which occur at temperatures and pressures that ought to disable brittle fracture. Recently, there is increasing evidence that the particular mechanisms enabling these earthquakes may be dependent on the tectonic setting in which they occur. Moreover, although intermediate-depth earthquakes are thought to exhibit few to no aftershocks in comparison to shallow earthquakes, productive aftershock sequences have been observed at intermediate depths in Japan, Colombia, Mexico and Alaska, among other regions. An enduring question, hence, is why certain intermediate-depth earthquake sequences appear to produce aftershocks whereas others do not, and whether or not the existence of aftershocks can be linked to the underlying mechanism, event depth or tectonic properties. To answer this, we study the aftershock productivity of intraslab earthquakes as a function of depth in diverse regions. We find a difference in b-value between regions with high aftershock productivity and low aftershock productivity. We also draw correlations between aftershock productivity and source properties of the earthquakes by region.

Presenting Author: Shanna Chu

Authors