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Extreme hydrometeorological events, a challenge for gravimetric and seismology networks
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  • Michel J Van Camp,
  • Olivier de Viron,
  • Alain Dassargues,
  • Laurent Delobbe,
  • Kristel Chanard,
  • Kevin Gobron
Michel J Van Camp
Royal Observatory of Belgium

Corresponding Author:[email protected]

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Olivier de Viron
La Rochelle University
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Alain Dassargues
Liège University
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Laurent Delobbe
Royal Meteorological Institute
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Kristel Chanard
IPGP
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Kevin Gobron
Royal Observatory of Belgium
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Abstract

Extreme events will become more common due to global change, requiring enhanced monitoring and pushing conventional observation networks to their limits. This encourages us to combine all the possible sources of information to obtain a complete picture of extreme events and their evolution. This commentary builds on an example of the July 2021 catastrophic floods that hit northwest Europe, for which the use of seismometer and gravimeter captures complementary data and brings a new understanding of the event and its dynamics. A sudden increase in seismic noise coincides with the testimony reporting on a “tsunami” downstream of the geophysical station. Concurrently, the gravimeter showed increasing saturation of the weathered zone, showing less and less water accumulation and increasing runoff. When rain re-intensified after a 3-hour break, the subsoil’s saturation state induced an accelerated runoff increase, as revealed by the river flow, in a much stronger way than during the rainy episodes just before. We show that the gravimeter detected the saturation of the catchment subsoil and soil in real-time. When the rain re-intensified, this saturation resulted in a sudden, devastating and deadly flood. Our study opens up the possibility of integrating real-time gravity in early warning systems for such events.
Apr 2022Published in Earth's Future volume 10 issue 4. 10.1029/2022EF002737