Implications of source complexity on earthquake rupture and interactions within Mendocino Triple Junction

The Mendocino Triple Junction (MTJ) is a geologically complex region that includes two transform faults and the subduction interface. The plate boundary deformations, along with internal deformations within the Gorda plate produce abundant seismicity recorded by global networks. Previous studies have found low strength near the thrust interface, and strong? depth variation of stress drops. The complex rupture characteristics of the 2015 M5.7 earthquake make it very challenging to model its rupture process [Gong and McGuire, 2017]. Using a global database of source time functions (STFs) based on the SCARDEC method [Vallee and Douet, 2016], we compute and examine the roughness of STFs for over 3000 earthquakes. The distribution of roughness for strike-slip earthquakes shows coherent spatial patterns, where almost all earthquakes in the MTJ region in the database including the M5.7 earthquake exhibit significant rupture complexity. In this study, we seek to better understand the patterns and control factors of rupture process of moderate earthquakes in this region, and relationships between earthquake rupture and earthquake triggering and interactions. We focus on the time periods with dense OBS arrays from Cascadia Initiative projects, and apply a time-domain iterative deconvolution method based on the empirical Green's function approach to obtain STFs, which are subsequently inverted for sub-event models to illustrate the spatiotemporal distribution of slip history along the fault zone, and to better understand how earthquake nucleate, propagate and arrest. We will investigate how earthquake rupture process influence aftershock distributions and stress interactions among different types of fault systems within this complex region.