EGU2020-8304, updated on 11 Jan 2021
https://doi.org/10.5194/egusphere-egu2020-8304
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

GRAVL: a new satellite mission concept aiming to detect earthquakes with a magnitude of 6.5 Mw and higher

Jerome Woodwark1, Marcel Stefko2, and the GRAVL development team*
Jerome Woodwark and Marcel Stefko and the GRAVL development team
  • 1School of Geoscience, University of Edinburgh, United Kingdom (s1686744@ed.ac.uk)
  • 2Eidgenössische Technische Hochschule Zurich, Zurich, Switzerland (stefko@ifu.baug.ethz.ch)
  • *A full list of authors appears at the end of the abstract

Data from the US and German Gravity Recovery And Climate Experiment (GRACE) showed indications of pre-, co-, and post-seismic mass redistributions associated with earthquakes down to a magnitude of 8.3 Mw. These demonstrated state-of-the-art capabilities in obtaining high spatial resolution space-based gravimetry, and helped to improve understanding of mantle rheology, potentially even providing a route to developing early warning capabilities for future seismic events. We describe a new mission concept, GRAvity observations by Vertical Laser ranging (GRAVL), which aims to extend the earthquake detection limit down to magnitude 6.5 Mw, significantly increasing the number of observable events.

GRAVL directly measures the radial component of the acceleration vector via “high-low” inter-satellite laser ranging, increasing gravity field sensitivity. A constellation of Low-Earth Orbit (LEO) satellites act as test masses, equipped with reflectors and high precision accelerometers to account for non-gravitational forces. Two or more larger satellites are placed above these, in Geostationary or Medium Earth Orbit (GEO / MEO), and measure the distance to the LEO satellites via time-of-flight measurement of a laser pulse. To do this, the GEO/MEO spacecraft are each equipped with a laser, telescope and detector, and additionally require highly  accurate timing systems to enable ranging accuracy down to sub-micron precision. To detect co-seismic mass redistribution events of the desired magnitude, we determine a gravity field measurement requirement of order 0.1 µGal at a spatial resolution of approximately 100 km over a 3-day revisit interval. These are challenging requirements, and we will discuss possible approaches to achieving them.

The GRAVL mission concept was developed during the FFG/ESA Alpbach Summer School 2019 by a team of science and engineering students, and further refined using the Concurrent Engineering approach during the Post-Alpbach Summer School Event at ESA Academy's Training and Learning Facility at ESEC-Galaxia in Belgium.

GRAVL development team:

A. Adler (1), N. Anthony (2), M. Archimbaud (3), S. Beeck (4), I. Bjorge-Engeland (5), E. Bogacz (6), F. Boutier (7), V. Camplone (8), H. Collier (9), C. Dandumont (10), O. Dhuicque (11), B. Drozd (12), M. Eizinger (13), M. Fayolle-Chambe (14), V. Galetsky (15), B. Linder (16), E. Lopez-Contreras (17), M. Milasevicius (18), F. Mueller (19), T. Nielsen (20), M. Noeker (21), S. Ocaña Losada (2), A. Pagu (22), J. Vilaboa Pérez (10), A. Putz (13), L. Salfenmoser (23), G. Salvia (24), A. Savu (25), L. Schreiter (26), M. Stefko (27), E. Weterings (2), D. Wischert (28), J. Woodwark (29), R. Zeif (30). 1: Duale Hochschule Baden-Württemberg, 2: Luleå University of Technology, 3: Ecole Polytechnique Féminine, 4: Technical University of Denmark, 5: University of Bergen, 6: University College Dublin, 7: École polytechnique fédérale de Lausanne, 8: International Research School of Planetary Sciences, 9: Trinity College Dublin, 10: University of Liège - Centre Spatial de Liège, 11: CNES/ONERA/Observatoire de Paris, 12: Warsaw University of Science and Technology, 13: Fachhochschule Wiener Neustadt, 14: Delft University of Technology, 15: Instituto Superior Tecnico, 16: Stockholm University, 17: Polytechnic University of Catalonia, 18: Vilnius Gediminas Technical University, 19: German Aerospace Center, 20: University of Oslo, 21: Royal Observatory of Belgium and Université catholique de Louvain, 22: University of Oxford, 23: TU Berlin, 24: Institut Politechnique des Sciences Avancees, 25: Technical University of Civil Engineering Bucharest, 26: University of Bern, Astronomical Institute, 27: Eidgenössische Technische Hochschule Zurich, 28: ESA, 29: University of Edinburgh, 30: Graz University of Technology.

How to cite: Woodwark, J. and Stefko, M. and the GRAVL development team: GRAVL: a new satellite mission concept aiming to detect earthquakes with a magnitude of 6.5 Mw and higher, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8304, https://doi.org/10.5194/egusphere-egu2020-8304, 2020

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