Seismic tomography at Popocatepetl volcano, Mexico

We performed the first 3D seismic tomography of the Popocatepetl volcano, Mexico, from the inversion of the P-wave arrival times of nearly 1500 earthquakes recorded by up to 11 seismic stations of the permanent CENAPRED-SSN network. We used the Bayesian tomographic algorithm developed by Monteiller et al. (2005) to perform this P-wave travel-time tomography and carefully choose optimal regularization hyper-parameters. Sensitivity tests show that the inversion is correctly constrained under the volcano from -1 to 4 km depth b.s.l.. At these depths, the optimal tomographic model mainly shows low-velocity volumes surrounded by higher-velocity volumes. Lateral heterogeneity is strong: the variation of the P-wave velocity may reach up to +/- 20% of the average value at a given depth. Low-velocity volumes correlate well with results from former geological and geophysical studies. (C) 2011 Elsevier B.V. All rights reserved.