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Monogenetic fields present significant diversity, yet this diversity has not been fully quantified, and its origin remains elusive. We studied two large subduction-related fields in Mexico, the Sierra Chichinautzin and Los Tuxtlas, that have distinct crustal stress regime and structures, magma compositions, vent types, and climatic conditions. Using recently available 5-m resolution topographical data, we located all the eruptive centers, studied their spatial distribution and analyzed scoria cone shapes in detail, calculating morphometric parameters for the best preserved. We then applied a set of statistical tools to analyze and compare the patterns of vent distribution, vent alignment, and diversity in cone shapes in these two fields. We observe that, despite their distinct setting, the two fields are similar in terms of vent distribution and cone morphology, which shows that this type of data cannot be used alone to infer the tectonic, magmatic, and climatic context of monogenetic fields. It also confirms previous results that the diversity in cone shapes (slope, height-to-diameter ratio) reflects processes that are common to all cones (e.g., ballistic emplacement followed by scoria avalanching on slopes), and hence do not vary significantly (at field-scale) with external parameters. Differences in the crustal stress regime had no apparent impact on vent distribution as the dikes followed active faults, irrespective of their motion. Climatic differences did not affect the shape variety of the studied cones probably because of their young ages (< 50,000 years old) and their location in a vegetated environment. The fields nevertheless differ in size and vent density, as well as scoria cone shape complexity and volume, which can be attributed to differences in the geometry of the magma source for its impact on the closeness of the dikes feeding the activity. Differences in the relative proportion of small cones in both fields are likely due to factors impacting eruptive style such as magma-water interaction, magma composition, and/or fissure lengths.

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We present a MATLAB App aimed to characterize the degree of erosion of monogenetic scoria cones from two independent sets of morphometric parameters. One quantifies the shape and size of undulations in DEM level contours through a novel parameter, the Average Erosion Index ( AEI ), using Elliptical Fourier Descriptors to calculate the wavelength spectra of undulations in selected contours over an ample range of resolutions of the database. The other is a more conventional set of parameters characterizing the vertical profiles of cones. This algorithm permits correcting those parameters for terrain inclination. These methods aim for a consistent assessment of the erosion-related relative ages of volcanoes in extensive monogenetic fields, from DEM data. The age-related degree of erosion is revealed by two main parameters: The Average Erosion Index ( AEI ), calculated from the Elliptic Fourier Descriptor spectrum of a scoria cone contour lines; and the aspect ratio of a scoria cone vertical profile, considering terrain inclinations, if it is assumed that all cones acquired the same morphology at the time of their formation eruptions. The Method provides erosion metrics from a sizable range of DEM resolutions. For age-related applications, it is recommended to use resolutions better than 12 m.