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On the Dynamic of Peierls Creep at Subduction Zones: Implication for Intermediate-Depth Lower Plane Earthquakes

Description: 

Most earthquakes occur within Earth's subduction zones, where oceanic plates, possessing negative buoyancy, descend into the underlying asthenosphere mantle at trench boundaries. The interactions between the subducting slab and the surrounding mantle generate substantial deformation, resulting in double zone seismic in subduction regions, but the controversy of earthquakes in the lower plane persists. The occurrence of seismic events is intricately linked to the strength of tectonic plates. Olivine is presumed to influence plate strength through its rheological properties. Previous studies predominantly focused on dislocation and diffusion creep, neglecting the significance of Peierls creep. The wide variance in experimental approaches and flow laws used yields a diverse range of parameters related to Peierls creep.

To examine the impact of Peierls creep on deformation mechanisms and stress states within subducting slabs, pseudo-two-dimensional numerical models were developed using LaMEM. Systematic exploration of parameters including activation energy, activation volume, and Peierls stress categorizes model outcomes into three regimes, delineating the effects of Peierls creep on slab deformation patterns. When Peierls stress or activation energy is low, signifying strong Peierls creep effects and a weak slab, the subduction angle becomes substantial, eventually leading to a flat lying slab at the base. Conversely, higher activation energy with the inclusion of activation volume indicates diminishing Peierls effect and a stronger slab, potentially causing slab retrogradation. Increasing activation energy, Peierls stress, and critical activation volume tend to segment the slab, resulting in a moderate subduction angle. Additionally, given the Peierls creep's alignment with the lower plane seismic zone within the subduction double seismic zone, there is speculation regarding a potential correlation between lower plane seismic activity and Peierls creep, offering a novel perspective on seismic origins.

Session: Numerical Modeling in Seismology: Developments and Applications - III

Type: Oral

Date: 5/1/2024

Presentation Time: 02:45 PM (local time)

Presenting Author: Rui

Student Presenter: Yes

Invited Presentation: 

Authors