MAPPING OF THE P-WAVE VELOCITY STRUCTURE BENEATH THE ECUADORIAN ANDES- EVIDENCE FOR CONTINUITY OF THE CENTRAL ANDES

Arrival times of P-waves of local and regionally recorded events are u sed to determine the one- and three-dimensional velocity structures of the crust and the upper mantle beneath the Ecuadorian Andes. The thre e-dimensional structure reveals two major features: (1) the average cr ustal velocity below the Interandean Depression is lower than the velo city found along the Cordilleras, and (2) beneath the Interandean Depr ession, tile depth of the Moho increases. Unfortunately, we do not hav e enough firmly determined data to tell how deep the Moho plunges from its average 50 km depth elsewhere. This structure is similar to the o ne observed farther South in the Central Andes of Peru-Bolivia.