Application of the Gauss theorem to the study of silicic calderas: The calderas of La Primavera, Los Azufres, and Los Humeros (Mexico)

摘要: Abstract We explored applications (including limitations) of Gauss's theorem to the study silicic calderas. First it enables us determine mass deficiency from Mass itself has also other potential applications. It make qualitative comparisons between can use test, in a quick way and as preliminary step formal gravity inversion, for feasibility caldera types simple geometry (i.e., piston subsidence funnel models). This application be done straightforward way, once been determined. For this purpose is converted volume material missing at caldera. Subsequently, example, respective diameter enable estimate height cylinder fitting model. If obtained parameters are congruent with known geology geophysical information then model may considered further inversion data detailed structure. Other models model) analyzed way. In particular, when working type, Gauss collapse (very difficult obtain based on geologic alone). These possible uses illustrated calderas La Primavera, Los Azufres, Humeros (Mexico). The these follow linear deficiency–diameter trend observed because their diameters deficiencies, Primavera Krakatau equiparable. comparison most importance considering that located neighbourhood metropolis (Guadalajara City). Since studies have already established calderas, we assessed used collapses. estimated subsidences (600 m), (500 Azufres (800 1200 m, respectively) supported by borehole data. relatively small subsidences, relation many western US, explained presence cylindrical sub-spherical magma chambers (of smaller size than those underlying US calderas—of Yellowstone, Valles, Long Valley example) an epicontinental setting young Quaternary rocks (against Precambrian cratonic basement US). A reassessment all available geological was done. limits were checked corrected necessary 2-D modeling, gradients, location volcanic vents. Regional tectonic lineaments might explain particular details structures. formed through piecemeal (controlled pre-caldera tectonics); example evolved incremental growth (as Vulsiniani Italy). comprises two contiguous emplaced regional depression.