EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Extreme hydrometeorological events, a challenge for geodesy and seismology networks

Michel Van Camp1, Olivier de Viron2, Alain Dassargues3, Laurent Delobbe4, and Kristel Chanard5
Michel Van Camp et al.
  • 1Seismology-Gravimetry, Royal Observatory of Belgium (
  • 2Littoral Environnement et Sociétés – LIENSs, U. La Rochelle, France
  • 3Hydrogeology & Environmental Geology, Urban & Environmental Enineering, U. Liege, Belgium
  • 4Royal Meteorological Institute of Belgium, Belgium
  • 5Université de Paris - IPGP, Géodésie – IGN, France

The use of seismometer and gravimeter captures complementary data and brings a new understanding of the July 2021 catastrophic floods in Belgium. A sudden increase in seismic noise coincides with the testimony reporting on a “tsunami” downstream of the Membach geophysical station, along the Vesdre valley. Concurrently, the gravimeter evidenced a rising saturation of the weathered zone, thus showing less and less water accumulation. When rain re-intensified after a 3-hour break, the saturated state of the subsoil induced an accelerated increase of the runoff, as revealed by the Vesdre River flow, in a much stronger way than during the rainy episodes just before. We show that a gravimeter can detect in real-time the saturation of the catchment subsoil and soil. This saturation resulted, when the rain re-intensified, in a sudden, devastating and deadly flood. This opens perspectives to use real-time gravity for early warnings of such events

How to cite: Van Camp, M., de Viron, O., Dassargues, A., Delobbe, L., and Chanard, K.: Extreme hydrometeorological events, a challenge for geodesy and seismology networks, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2454,, 2022.