Juhel, K.Montagner, J. P.Valle, M.Ampuero, J. P.Barsuglia, M.Bernard, P.Clevede, E.Harms, J.Whiting, B. F.2025-03-222025-03-22Scopus:85060268441https://dspace-test.anu.edu.au/handle/1885/733730401As soon as an earthquake starts, the rupture and the propagation of seismic waves redistribute masses within the Earth. This mass redistribution generates in turn a long-range perturbation of the Earth gravitational field, which can be recorded before the arrival of the direct seismic waves. The recent first observations of such early signals motivate the use of the normal mode theory to model the elastogravity perturbations recorded by a ground-coupled seismometer or gravimeter. Complete modelling by normal mode summation is challenging due to the very large difference in amplitude between the prompt elastogravity signals and the direct P-wave signal.We overcome this problem by introducing a two-step simulation approach. The normal mode approach enables a fast computation of elastogravity signals in layered self-gravitating Earth models. The fast and accurate computation of gravity perturbations indicates instrument locations where signal detection may be achieved, and may prove useful in the implementation of a gravity-based earthquake early warning system.We thank Philippe Lognonn\u00E9, Yann Capdeville, David Al-Attar and Olivier Coutant for making their codes publicly available, and Thomas Heaton for stimulating discussions. We thank engineers involved in the installation, maintenance and data distribution of broad-band seismic stations. High-quality signals come from the Global Seismograph Network (ASL/USGS 1988), the New China Digital Seismograph Network (ASL/USGS 1992), the National Research Institute for Earth Science and Disaster Resilience/F-net, GEOSCOPE (IPGP/EOST 1982) and the Northeast China Extended Seismic Array (Ni 2009), all publicly available at the IRIS data management center, the Institut de Phys ique du Globe de Paris (IPGP) data center or the F-net data center. We acknowledge the financial support from the UnivEarthS Labex program at Sorbonne Paris Cit\u00E9 (grants ANR-10-LABX-0023 and ANR-11-IDEX-0005-02) and the financial support of the Agence Nationale de la Recherche through the grant ANR-14-CE03-0014-01. JPM acknowledges the financial support of I.U.F. (Institut uni-versitaire de France). JPA acknowledges funding by the French government through the \"Investissements d\u2019Avenir UCAJEDI\" project managed by the Agence Nationale de la Recherche (grant ANR-15-IDEX-01). Numerical computations were partly performed on the S-CAPAD platform, IPGP, France.13EnglishPublisher Copyright: © 2018 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society.Numerical solutionsTheoretical seismologyTime variable gravityTransient deformation2019-02-0110.1093/gji/ggy436http://www.scopus.com/inward/record.url?scp=85060268441&partnerID=8YFLogxK