Year: 2025
Type: article
Abstract: Understanding the dynamics of microearthquakes is a timely challenge with the potential to address current paradoxes in earthquake mechanics, and to better understand earthquake ruptures induced by fluid injection. We perform fully 3D dynamic rupture simulations caused by fluid injection on a target fault for Fault Activation and Earthquake Ruptures experiments generating M w ≤ 1 earthquakes. We investigate the dynamics of rupture propagation with spatially variable stress drop caused by pore pressure changes and assuming different slip‐weakening constitutive parameters. We show that the spontaneous arrest of propagating ruptures is possible by assuming a high fault strength parameter S, that is, a high ratio between strength excess and dynamic stress drop. In faults with high S values (low rupturing potential), even minor variations in D c (from 0.45 to 0.6 mm) have a substantial effect on the rupture propagation and the ultimate earthquake size. Modest spatial variations of dynamic stress drop determine the rupture mode, distinguishing self‐arresting from run‐away ruptures. Our results suggest that several characteristics inferred for accelerating dynamic ruptures differ from those observed during rupture deceleration of a self‐arresting earthquake. During deceleration, a decrease of peak slip velocity is associated with a nearly constant cohesive zone size. Moreover, the residual slip velocity value (asymptotic value for a crack‐like rupture) decreases to nearly zero. This means that an initially crack‐like rupture becomes a pulse‐like rupture during spontaneous arrest. These findings highlight the complex dynamics of small induced earthquakes, which differ from solutions obtained from conventional crack‐like models of earthquake rupture.
DOI: 10.1029/2024jb029621
Authors: Francesco Mosconi, Elisa Tinti, Emanuele Casarotti, Alice‐Agnes Gabriel, Antonio Pio Rinaldi, Luca Dal Zilio, Massimo Cocco
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: Center of Excellence for Exascale in Solid Earth - Second Phase, Characteristic Science Applications for the Leadership Class Computing Facility, G3787276462, G434337789, Collaborative Research: Frameworks: Quakeworx - An extensible software framework for earthquake simulations, Geosphere INfrastructures for QUestions into Integrated REsearch, A Digital Twin for GEOphysical extremes, Center Operations: Cascadia Region Earthquake Science Center (CRESCENT), Collaborative Research: Toward an integrated modeling framework for physics-based estimates of megathrust rupture potential
OpenAlex ID: W4408499123