Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1, 2017 | Supplemental Material
Journal Article Open

Observations and modeling of the elastogravity signals preceding direct seismic waves


After an earthquake, the earliest deformation signals are not expected to be carried by the fastest (P) elastic waves but by the speed-of-light changes of the gravitational field. However, these perturbations are weak and, so far, their detection has not been accurate enough to fully understand their origins and to use them for a highly valuable rapid estimate of the earthquake magnitude. We show that gravity perturbations are particularly well observed with broadband seismometers at distances between 1000 and 2000 kilometers from the source of the 2011, moment magnitude 9.1, Tohoku earthquake. We can accurately model them by a new formalism, taking into account both the gravity changes and the gravity-induced motion. These prompt elastogravity signals open the window for minute time-scale magnitude determination for great earthquakes.

Additional Information

© 2017 American Association for the Advancement of Science. Received 11 June 2017; accepted 2 November 2017. We are grateful to the developers of AXITRA, and more specifically to O. Coutant for making his code publicly available, both in the moment tensor and in the single-force configurations. We thank engineers involved in the installation, maintenance, and data distribution of broadband seismic stations. High-quality signals come from the Global Seismograph Network (https://doi.org/10.7914/SN/IU), New China Digital Seismograph Network (https://doi.org/10.7914/SN/IC), National Research Institute for Earth Science and Disaster Resilience /F-net, GEOSCOPE (https://doi.org/10.18715/GEOSCOPE.G), and Northeast China Extended Seismic Array (https://doi.org/10.7914/SN/YP_2009) networks, all publicly available at the IRIS data management center (http://ds.iris.edu/ds/nodes/dmc/), Institut de Physique du Globe de Paris (IPGP) data center (http://datacenter.ipgp.fr/), or the F-net data center (www.fnet.bosai.go.jp/top.php). Global Centroid-Moment-Tensor Project (www.globalcmt.org/) source parameters of the Tohoku earthquake were very valuable for this study. The careful reviews of three anonymous reviewers were very valuable to clarify observational and theoretical aspects of the initial manuscript. We acknowledge T. Heaton for stimulating discussions that pushed us to carefully study the role of the gravity-induced acceleration. J. Harms provided valuable comments on the relationships between gravity and elastic perturbations. Most numerical computations were performed on the S-CAPAD platform, IPGP, France. We acknowledge the financial support from the GEOSCOPE program (funded by CNRS Institute for Earth Sciences and Astronomy and IPGP), the UnivEarthS Labex program at Sorbonne Paris Cité (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02), and the Agence Nationale de la Recherche through grant ANR-14-CE03-0014-01. Seismic Analysis Code (http://ds.iris.edu/ds/nodes/dmc/software/downloads/sac/) and Generic Mapping Tools (http://gmt.soest.hawaii.edu/projects/gmt) free software packages were used for data processing and figure preparation.

Attached Files

Supplemental Material - aao0746_DataS1.tar.zip

Supplemental Material - aao0746_Vallee_SM.pdf


Files (6.0 MB)
Name Size Download all
1.3 MB Preview Download
4.7 MB Preview Download

Additional details

August 19, 2023
October 17, 2023