On June 8th, Dr. Yu Chen from SUNY at Stony Brook (Stony Brook University) was invited by Dr. Yan Lu to give a presentation entitled “Source process of global large deep-focus earthquakes” at the IGGCAS. 

In his presentation, Dr. Yu Chen introduced the recent progress in understanding deep-focus earthquakes. With his research team, he has developed a multiple source inversion method to study the global large deep-focus earthquakes with Mw larger than 7 and depth greater than 400 km. Their method decomposes a large earthquake into several sub-events, and resolves the spatio-temporal distribution and focal mechanisms of the sub-events. Their results indicate that most earthquakes cannot be modeled in a single fault plane. The source geometry of some earthquakes is inconsistent with the slab geometry, which excludes transformational faulting as a potential mechanism. The geographical changes in the focal mechanisms suggest that the earthquakes occurred in pre-existing weak zones. They proposed that, the earthquakes may be best interpreted as cascading failure of shear instabilities in pre-existing weak zones, with the stress perturbations triggering subsequent earthquakes. 

 Dr. Yu Chen is giving the presentation