Seminar - Understanding the Complexity of Fluid-Induced Microearthquake Ruptures: Insights from High-Resolution Observations and 3D Dynamic Modeling

Speaker: Prof. Elisa Tinti – Sapienza Università di Roma | Thursday 23 April 2026 | 4,30 p.m. - Classroom 1F

23.04.2026

Understanding the dynamics of microearthquakes is a key challenge in modern seismology, particularly in the context of fluid-induced seismicity. We exploit unique datasets from hydraulic stimulation experiments at the Bedretto Underground Laboratory (Switzerland), where dense near-fault monitoring networks recorded seismic sequences with magnitudes up to Mw ~0. These high-quality data enable robust estimates of source parameters, showing stress drops on the order of MPa, consistent with near scale-invariant behavior.
Building on these observations, we run fully 3D dynamic rupture simulations and focal mechanism inversion to interpret the observed seismicity. We investigate how fluid injection alters fault stress conditions and controls rupture propagation. Our results show that even small variations in stress or fault properties can determine whether ruptures remain self-arresting or grow until encountering structural barriers.
Finally, by integrating synthetic simulations with spectral inversion, we identify waveform features—such as high-frequency radiation and P/S corner frequency ratios—that help discriminate between rupture arrest mechanisms. This work highlights the value of combining high-resolution observations with physics-based modeling to better understand microearthquakes and induced seismicity.