Global tomography using seismic hum

A Haned (1, 2) , E Stutzmann (1) , M Schimmel (3) , S Kiselev , A Davaille (4) , A Yelles-Chaouche (2)

1 IPGP - Institut de Physique du Globe de Paris
2 CRAAG - Centre de Recherche en Astronomie Astrophysique et Géophysique
3 Institute of Earth Sciences Jaume Almera
4 FAST - Fluides, automatique, systèmes thermiques

We present a new upper-mantle tomographic model derived solely from hum seismic data. Phase correlograms between station pairs are computed to extract phase-coherent signals. Correlograms are then stacked using the time-frequency phase-weighted stack method to build-up empirical Green's functions. Group velocities and uncertainties are measured in the wide period band of 30-250 s, following a resampling approach. Less data are required to extract reliable group velocities at short periods than at long periods, and 2 yr of data are necessary to measure reliable group velocities for the entire period band. Group velocities are first regionalized and then inverted versus depth using a simulated annealing method in which the number and shape of splines that describes the S-wave velocity model are variable. The new S-wave velocity tomographic model is well correlated with models derived from earthquakes in most areas, although in India, the Dharwar craton is shallower than in other published models.

Mots clés: Time-series analysis; Surface waves and free oscillations; Seismic tomography

Domaines: Sciences de la Terre

A Haned, E Stutzmann, M Schimmel, S Kiselev, A Davaille, et al.. Global tomography using seismic hum. Geophysical Journal International, 2015, 204, pp.1222 - 1236. ⟨10.1093/gji/ggv516⟩. ⟨hal-03617138v2⟩