Mechanics of spontaneously arrested laboratory earthquakes
Event details
| Date | 14.10.2021 |
| Hour | 16:00 › 17:00 |
| Speaker | Prof. David Kammer Computational Mechanics of Building Materials, ETH Zurich |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract: Earthquakes, which we experience as ground shaking, consist of sudden relative motion between tectonic plates. The underlying mechanical process involves three phases – the initiation of local slip, its growth along the tectonic fault, and its arrest. This rupture-like process is governed by physics at multiple length scales, making it a highly complex phenomenon that remains only partially understood. This is particularly true for earthquake arrest, which directly affects its magnitude. The current understanding of earthquake arrest is almost exclusively based on remote measurements because most laboratory experiments are too small to allow rupture arrest to occur naturally. However, recently developed large-scale laboratory experiments on granite blocks provide the necessary fault length to generate laboratory earthquake ruptures that not only nucleate and propagate, but also arrest, spontaneously. These experiments provide an opportunity to reexamine and better understand the physics governing earthquake arrest conditions. In this talk, we will discuss various analytical and numerical models that enable in-depth analysis, interpretation and extrapolation of results from such large-scale laboratory earthquake experiments. The results suggest that rupture arrest (at least in the laboratory) is controlled by the driving force rather than by the resistance, as often assumed. Further, we will discuss fault fracture energy, which is a key parameter in the arrest of earthquake ruptures. We will present a minimal numerical model with scale-invariant fault fracture energy in accordance with laboratory observations. However, when applying seismological approaches to estimate the fault fracture energy, it appears to be scale-dependent, similar to field observations, despite being scale-invariant. Therefore, the model reconciles conflicting observations from the field and the laboratory, and provides a pathway for more realistic models of earthquake arrest mechanisms.
Practical information
- General public
- Registration required
Organizer
- ETH Zurich & EPFL Lausanne
Contact
- ETH, Prof. George Haller [email protected] EPFL, Prof. John Kolinski, [email protected]