Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake

Jean-Paul Montagner (1) , Kévin Juhel (1) , Matteo Barsuglia (2) , Jean Paul Ampuero (3) , Eric Chassande-Mottin (2) , Jan Harms (4) , Bernard Whiting (5) , Pascal Bernard (1) , Eric Clevede (6) , Philippe Lognonné (6)

1 IPGP - Institut de Physique du Globe de Paris
2 APC (UMR_7164) - AstroParticule et Cosmologie
3 Seismological Laboratory, California Institute of Technology, 1200 E. California Blvd., Pasadena, California 91125, USA.
4 Università degli Studi di Urbino 'Carlo Bo'
5 UF|Physics - Department of Physics [Gainesville]
6 IPGP - Institut de Physique du Globe de Paris

Transient gravity changes are expected to occur at all distances during an earthquake rupture, even before the arrival of seismic waves. Here we report on the search of such a prompt gravity signal in data recorded by a superconducting gravimeter and broadband seismometers during the 2011 Mw 9.0 Tohoku-Oki earthquake. During the earthquake rupture, a signal exceeding the background noise is observed with a statistical significance higher than 99% and an amplitude of a fraction of mGal, consistent in sign and order of magnitude with theoretical predictions from a first-order model. While prompt gravity signal detection with state-of-the-art gravimeters and seismometers is challenged by background seismic noise, its robust detection with gravity gradiometers under development could open new directions in earthquake seismology, and overcome fundamental limitations of current earthquake early-warning systems imposed by the propagation speed of seismic waves.

Domaines: Planète et Univers [physics]; Sciences de la Terre

Jean-Paul Montagner, Kévin Juhel, Matteo Barsuglia, Jean Paul Ampuero, Eric Chassande-Mottin, et al.. Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake. Nature Communications, 2016, 7 (1), ⟨10.1038/ncomms13349⟩. ⟨insu-02279303⟩