Crustal imaging of western Michoacan and the Jalisco Block, Mexico, from Ambient Seismic Noise

Detailed crustal imaging of western Michoacan and the Jalisco Block is obtained from ambient noise tomography. Results show a deep and well-delineated volcanic system below the Colima volcano complex, rooting up to similar to 22 km depth, with a shallow magmatic chamber constrained to the first similar to 7 km. A shallow low-velocity system to the south of the Chapala rift and west of the Michoacan-Guanajuato volcanic field merges, underneath the Colima rift, with the Colima volcano system at about 20 km depth, honoring the geometry of the Trans-Mexican Volcanic Belt. For depths greater than similar to 30 km, low-velocity features become parallel to the slab strike, right beneath the Mascota, Ayutla and Tapalpa volcanic fields, suggesting the presence of the mantle wedge above the Rivera plate. All mentioned low-velocity bodies are spatially correlated with the superficial volcanic activity suggesting their magmatic origin so that, the shallower these bodies, the younger are the associated volcanic deposits. Along the coast, different depths of the uppermost layer of the Rivera and the Cocos plates suggest that the latter plate subducts with an angle similar to 9 degrees steeper than the former. (C) 2014 Elsevier B.V. All rights reserved.