News

This experiment was our first attempt to induce a magnitude 1.0 earthquake in the Earthquake Physics Testbed at BedrettoLab. A magnitude 1.0 event is very small and cannot be felt, but it is an important scientific target. By observing earthquakes of this size under controlled conditions, we can better understand how earthquakes start, grow and stop. Using controlled high‑pressure fluid injections, we were able to activate a specific fault zone and set the surrounding rock in motion.
We recorded more than 12,000 very small earthquakes (“microquakes”) within the experimental area. These events had magnitudes between −5 and −0.1, meaning the target magnitude of 1.0 was not yet reached. The injections were stopped because the activity began to move away from the most densely monitored zone. Despite this, the experiment produced an exceptionally rich dataset that helps us better understand how faults are activated.
A key part of the experiment is our advanced monitoring system. It allows us to measure seismic waves across a wide range of frequencies and amplitudes, as well as other important physical parameters. One important component is a network of fibre‑optic cables installed in boreholes and along the tunnel floor. Using a technique called Distributed Acoustic Sensing (DAS), these cables can detect both ground shaking and very small permanent deformations caused by earthquakes. Such deformations are well known in large natural earthquakes but are rarely measurable in small events.
In addition, a specially designed digital control system allowed us to run and monitor the entire experiment remotely from Zurich. This system is a key part of our safety concept and performed reliably throughout the experiment. For example, during an unexpected electrical short circuit, the system immediately shut down the experiment as designed, preventing further damage and demonstrating the effectiveness of the safety concept.
Although the detailed analysis is still ongoing, the potential of our monitoring system is already clear. For example, the recorded data (see animation) provides a detailed view of how and where the fault was activated.
Based on these results, we are now preparing a series of follow‑up experiments. The goal is to gradually increase the maximum magnitude towards 1.0. These experiments will allow us to observe earthquake processes with unprecedented detail and represent an important step towards controlled earthquake experiments beyond BedrettoLab.