Time-reversal imaging of seismic sources and application to the great Sumatra earthquake

Carene Larmat (1, 2) , Jean-Paul Montagner (1) , Mathias Fink (3) , Yann Capdeville (1) , Arnaud Tourin (3) , Eric Clévédé (1)

1 IPGP - Institut de Physique du Globe de Paris
2 Seismological Laboratory
3 LOA - Laboratoire Ondes et Acoustique (UMR 7587)

The increasing power of computers and numerical methods (like spectral element methods) allows continuously improving modelization of the propagation of seismic waves in heterogeneous media and the development of new applications in particular time reversal in the three-dimensional Earth. The concept of time-reversal (hereafter referred to as TR) was previously successfully applied for acoustic waves in many fields like medical imaging, underwater acoustics and non destructive testing. We present here the first application at the global scale of TR with associated reverse movies of seismic waves propagation by sending back long period time-reversed seismograms. We show that seismic wave energy is refocused at the right location and the right time of the earthquake. When TR is applied to the Sumatra-Andaman earthquake (26 Dec. 2004), the migration of the rupture from the south towards the north is retrieved. Therefore, TR is potentially interesting for constraining the spatio-temporal history of complex earthquakes.

Mots clés: 9820 General or Miscellaneous: Techniques applicable in three or more fields; 7209 Seismology: Earthquake dynamics (1242); 7215 Seismology: Earthquake source observations (1240); 7290 Seismology: Computational seismology; 9820 General or Miscellaneous: Techniques applicable in three or more fields.

Domaines: Géophysique [physics.geo-ph]; Volcanologie

Carene Larmat, Jean-Paul Montagner, Mathias Fink, Yann Capdeville, Arnaud Tourin, et al.. Time-reversal imaging of seismic sources and application to the great Sumatra earthquake. Geophysical Research Letters, 2006, 33 (19), pp.L19312. ⟨10.1029/2006GL026336⟩. ⟨insu-01390090⟩