I13: Geophysics and gravitational wave interferometric detectors

This project was previously Exploratory Project 3 and evolved into Interface Project 13 in 2017.

 

> Read the articles connected to the project.

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    Virgo_view_0.jpgGravitational 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.

    > To know more about Virgo, visit the official website: https://wwwcascina.virgo.infn.it/

     

    This project started with a completely exploratory nature. The first success has been to allow exchanges between the APC and IPGP geophysical and gravitational communities to explore new ideas and methods. Moreover, around our APC-IPGP team, several international collaborations have started, both on the geophysical 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 analysed some research possibilities (use of Virgo as inclinometer and long base extensometer, study of gravity gradient noise, study of gravitational disturbances due to earthquakes).

    We then identified an original research direction: the detection of rapid gravitational disturbance produced by mass redistribution during earthquakes, and its potential application to improving early warning systems for earthquakes.

    In 2017, the Exploratory project became an Interface project and presented beautiful results, fruits of the work of previous years with, among others, the following publications in Science and Nature :

    Observations and modeling of the elastogravity signals preceding direct seismic waves. Martin Vallée, Jean Paul Ampuero, Kévin Juhel, Pascal Bernard, Jean-Paul Montagner, Matteo Barsuglia. December 1, 2017, Science, DOI : 10.1126/science.aao0746
    See the article “Tiny changes in Earth’s gravitational field could help predict tsunami’s size”.

    Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake. Jean-Paul Montagner, Kévin Juhel, Matteo Barsuglia, Jean Paul Ampuero, Eric Chassande-Mottin, Jan Harms, Bernard Whiting, Pascal Bernard, Eric Clévédé & Philippe Lognonné, Nature Communications, doi:10.1038/ncomms13349
    See the article “Publication : Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake.”

    While research continues, a documentary film is being produced to present the results obtained by the I13 group to the general public: “NAMAZU”. The motivation behind this film is twofold. First, explain to a wide audience these latest developments in seismology and how they could help reduce the damage caused by large earthquakes. And two, tell the story of a close and fruitful collaboration between geophysicists and gravitational wave physicists. This project is truly a major illustration of the power of interdisciplinarity and the ability to generate new ideas by combining different points of view on the same subject, an idea that is at the heart of the collaborations promoted by UnivEarthS.
    See the “NAMAZU” film presentation page

     

     

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    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).

     

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    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.

     

     

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    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

     

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