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Interactions Between Megathrust and Adjacent Crustal Faults

Description: 

How do megathrust earthquakes interact with crustal earthquakes on faults adjacent to the subduction interface zone? Much evidence shows that earthquakes with magnitudes greater than Mw > 8 produce a release of stress in the upper crust that could trigger crustal faults and vice versa. To understand this problem, we build a 3D model of a northwest striking crustal fault that connects directly to a north-south striking subduction zone interface, where on both faults we prescribe rate and state frictional properties and effective normal stress consistent with the pressure and temperature conditions expected at depth. The convergence at the subduction zone is set to 70 mm/year, and zero for the crustal fault. We feed these data to a quasi-dynamic boundary element code, where we model slip evolution and tractions on both faults. Our results show that fault planes to the north of a Mw~ 8.6 interplate co-seismic rupture produce Mw7crustal earthquakes, with an average recurrence of ~1100 years. Similarly, our results demonstrate that active crustal fault are linked to seismic segmentation along the subduction zone, avoiding the propagation of large megathrust Mw~9. This means that with knowledge of crustal fault locations along subduction zones, one can potentially estimate earthquake recurrence models for both types of faults, as well as maximum magnitudes along different segments of subduction zones.

Session: Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Jorge Crempien

Student Presenter: No

Invited Presentation: 

Authors