I13: Geophysics and gravitational wave interferometric detectors
This project was previously Exploratory Project 3 and evolved into Interface Project 13 in 2017.
Gravitational waves are a prediction of Einstein’s theory of General Relativity. They are ripples in the space-time metric produced by cataclysmic astrophysical events. The direct detection of gravitational waves provides not only an important test of General Relativity, it also represent a new way to observe the Universe. The detection principle is based on the measurement of the space-time deformation between test masses with high-precision optical interferometers. The sensitivity of those instruments is limited at low frequency by seismic noise, due to geological and human activity. Geological activity affects the interferometric detectors, and conversely – for the same reason – the interferometric detectors can be used to extract information on the geological activity.
The goal of this project is to explore the possibility to use the data of the Virgo interferometer to extract useful geophysical information
Follow this link to know more about Virgo : https://wwwcascina.virgo.infn.it/
POSITION NAME SURNAME LABORATORY NAME GRADE, EMPLOYER WP leader Matteo Barsuglia APC DR2, CNRS WP co-leader Jean-Paul Montagner IPGP Professor, Paris Diderot WP member Kevin Juhel IPGP Doctorant, Paris Diderot WP member Donatella Fiorucci APC Post-doc WP member Pascal Bernard IPGP Physicien, CNRS WP member Eric Chassande-Mottin APC DR2, CNRS
Collaborations with J.Harms (INFN Florence), B.Whiting (Florida University), J.-P.Ampuero (Caltech), M.Ando (Tokyo University), F.Sorrentino (INFN Genova).
This project started with a completely exploratory nature. The first success of the E3 WP is to have allowed exchanges between the geophysical and gravitational-wave communities at APC and IPGP in order to explore new ideas and methods. Moreover, around our APC-IPGP team, several international collaborations started, both on the geophysics side (Prof. Ampuero, Caltech-seismolab) and on the gravitational-wave side (Prof.Withing, U.Florida and Dr.Harms, INFN-Urbino). During this first exploratory phase (2012-2014) we have analyzed a few research possibilities (use of Virgo as long-base tiltmeter and strainmeter, study of the gravity-gradient noise, study of the prompt gravity perturbations due to earthquakes). We have then identified an original research direction: the detection of the prompt gravity perturbation produced by the mass redistribution during earthquakes, and its potential application to the improvement of earthquake early-warning systems.
Main scientific results achieved:
1) Search of an instantaneous gravity signal from the Tohoku 2011 earthquake
2) First analytical computation of the prompt gravity signal by an earthquake.
3) Simulation of the gravity signal with the method of Earth normal modes
4) Feasibility study of a gravity strainmeter
4) A feasibility study for a gravity-based earthquake early warning system network
The goal is to have in the next months a general publication about gravity early warning system, summarizing the goals, the outcome of the feasibility studies of the detector and the implementation strategy. Some parts of this paper have been already written.
The objectives for 2018-2019 are threefold:
1) conclude the feasbibility study of a gravity-based early warning system.
2) Study the local gravity fluctuations study for gravitational-wave detectors.
3) Use of Virgo data for geophysics.
J. Harms, J.-P. Ampuero, M. Barsuglia, E.Chassande-Mottin, J.-P. Montagner, S. N. Somala and B. F.Whiting,
Transient gravity perturbations induced by earthquake rupture,
Geophys. Journal International (2015) 201, 1416-1425
Jean-Paul Montagner , Matteo Barsuglia , Kévin Juhel , Jean-Paul Ampuero, Eric Chassande-Mottin, Jan Harms, Bernard Whiting, Pascal Bernard, Eric Clévédé, Philippe Lognonné
Prompt gravity signal due to the 2011 Tohoku-oki earthquake
Nature Communications, 2016, DOI: 10.1038/ncomms13349
Vallée et al.,
Observation and modeling of the elasto-gravity signal preceeding the direct seismic waves,
Science 358, 1164–1168 (2017)
D.Fiorucci et al.,
Impact of infrasound atmospheric noise on gravity detectors used for astrophysical and geophysical applications
Physical Review D., January 2018, DOI: 10.1103/PhysRevD.97.062003