Possible Precursory Slow-Slip to Two ML ∼3 Mainevents of the Diemtigen Microearthquake Sequence, Switzerland

How earthquakes initiate is still a largely debated question in earthquake science. On the lab scale, rupture initiation is well studied, and detailed models of how rupture nucleation evolves have been developed. Contrarily, for real earthquakes, only a few high-resolution observations of this process are available today, mostly limited to mainshock magnitudes > M5. Consequently, there is still no consensus on whether and how laboratory results can be transferred to real earthquakes. Here we show that rupture nucleation phenomena observed on the lab scale can also be imaged on the microearthquake-scale with little instrumental effort. Our results highlight the potential of the applied analysis workflow to significantly improve the observation quality of seismicity patterns and immediate foreshock phenomena in microearthquake sequences. Our approach can help to narrow the existing observational gap to the lab scale and may contribute to a better understanding of the mechanisms of earthquake initiation in the future.

Automated summary

The initiation of earthquakes remains a debated topic in earthquake science, with a gap between laboratory studies and real earthquake observations. The study shows that rupture nucleation phenomena observed on the lab scale can also be imaged on the microearthquake-scale, improving the quality of seismicity patterns and immediate foreshock phenomena. This approach may help bridge the observational gap between laboratory and field studies to enhance understanding of earthquake initiation mechanisms in the future.