Understanding earthquake physics
Earthquakes are one of the most significant hazards for human society, and, at the same time, remain the most elusive. Improving the ability to forecast earthquakes is one of the main challenges remaining for the natural sciences. With the European Research Council (ERC) Synergy project “Fault Activation and Earthquake Rupture” (FEAR), a consortium of scientists from the Eidgenössiche Technische Hochschule Zürich (ETH Zurich) in Switzerland, the Rheinisch-Westfälische Hochschule (RWTH Aachen University) in Germany, and the Instituto Nazionale di Geofisica e Vulcanologia (INGV) in Italy are conducting a suite of ambitious experiments in the world-unique Bedretto Underground Laboratory for Geosciences and Geoenergy (BedrettoLab), an underground experimental facility in the Bedretto Tunnel, located at 1000m depth under the Swiss Alps.
The core idea of FEAR is to gain understanding on how earthquakes start and stop by using hydraulic stimulation to modify stress and initiate small non-damaging earthquakes (magnitude ~1.0 events on fault patches of 10-50m scale) on candidate faults in the vicinity of the Bedretto Tunnel. A dense network of multidisciplinary sensors will capture the rupture preparation phase, the earthquake rupture, and the post-rupture response of the rock mass. These experiments will give unprecedented up-close near-field insight into the physics of earthquake processes, contribute to pushing forward the current limits on earthquake predictability and advance the state-of-the-art in safe use of geoenergy.
Second M0 experiment finished successfully
The second multi-day hydraulic stimulation conducted in the framework of FEAR was finished successfully at the end of August. A team of about ten people monitored a stimulation lasting for about three days, injecting water with a pressure of 20 MPa.
As anticipated, the injection triggered a high level of microseismicity: our real-time monitoring workflow detected several thousand tiny earthquakes. The two largest events reached a magnitude of around -1.0. This is equivalent to when rocks rupture in an area of one meter in diameter and move by up to 1 millimetre.
The experiment was conducted according to a previously designed protocol. With the new remote-control system, the entire experiment and monitoring could be conducted from a control room at ETH Zurich and the Barracke near the tunnel entrance in Ronco, with no one in the tunnel.
Now, the team is busy analysing the rich data set and preparing for the next experiments in November and December 2024.
Continuation of the M0 experiment
Following the successful M0 experiment in late April, a new extended hydraulic stimulation experiment is scheduled for late August. The objective is to replicate the results of the previous test, which triggered, as planned, an earthquake with a magnitude of about 0. The now schedulded experiment will involve a shorter, high-pressure stimulation (20 MPa) lasting a maximum of three days.
This approach will help determine if the seismicity characteristics remain consistent with or differ from the prior experiment, which involved several days of rock mass preconditioning at intermediate pressures (15 MPa).
The potential risks associated with these experiments are considered low. However, safety measures have been implemented, including remote-controlled pump circuits that allow the experiments to be conducted without personnel in the tunnel. Additionally, predefined thresholds for magnitude and ground motion will trigger the halt of the injection to avoid any dangerous ground motions to occur.
Find out more about our experiments here
FEAR Science day on 17th September
The FEAR team met for two days at ETH Zurich to present their research and prepare the FEAR 1 Experiment. There were almost 40 participants and 13 presentations focused on the M0 experiment and the fault characterization in preparation for the FEAR1 experiment.
FEAR annual meeting (13-15th March 2024)
The FEAR annual meeting was held in Aachen this year from 13 to 15th March. The meeting included presentations and updates of each working group as well as poster sessions.
Besides fruitful discussions on FEAR and the upcoming experiments, some social activities like a geological tour of Aachen gave opportunities to broaden the horizon and also have some fun.
ERC TECTONIC-FEAR Seminars on Earthquake Physics
The weekly virtual seminars on the physics of earthquake faulting and the application of Machine Learning to earthquake science are available online.