18.116.88.128

2022 Rupture styles and recurrence patterns in seismic cycles linked to physical properties of the fault zone

By Shiying Nie

University of Southern California

Category

Webinars

Published on

Description

Rupture styles emerge in a broad range of rupture styles, from slow-slip events collocated with or without tremors to pulse-like earthquake sequences. Meanwhile, Earthquake catalogs exhibit various recurrence patterns, from periodic and characteristic earthquakes to chaotic sequences with super-cycles, aftershocks and dissimilar ruptures. The underlying physical mechanisms of these phenomena are usually documented separately and the potential connection between them is poorly understood. Here, we explore a wide range of frictional properties using quasi-dynamic models of seismic cycles in two dimension to assess the link between rupture style and recurrence patterns. We obtain a broad spectrum of rupture behaviors controlled by several non-dimensional parameters, including the Dieterich-Ruina-Rice number Ru, which is the ratio of asperity to a characteristic nucleation size, and Rb, which reflects the relative amplitude of weakening and strengthening effects. Seismogenic slow-slip events are the natural behavior of near-velocity neutral condition (low Rb) with a small characteristic nucleation size (high Ru), which is commonly found below the seismogenic zone. The deviation from periodic and characteristic recurrence behaviors are responses of homogeneous or compliant fault-zone models with high Ru numbers. The presence of a compliant zone can be incorporated into the Ru number in quasi-dynamic simulations. Observations of rupture characteristics and recurrence patterns can bring useful constraints on the physical properties of fault zones.

Tags