Circular features in the Trans-Mexican Volcanic Belt

One hundred and ninety-one circular or elliptical features have been located on Landsat imagery of the Trans-Mexican Volcanic Belt (TMVB). The origin of most of these features is unknown. Nine have been recognized as collapse calderas (clearly visible on Landsat imagery) and studied in detail, while an equally small number have been tentatively identified as such but not thoroughly investigated. On the basis of the identification of at least five of the nine calderas through their detection on Landsat images, it is proposed that the present inventory is a reliable base to extend the census of the TMVB confirmed calderas, now clearly too small for a population of roughly 8000 volcanic centers, many of which emitted large volumes of felsic pyroclastic products.