Volcanic evolution through geomorphological mapping: A case study of Cerro Bravo volcano (Colombia)

Abstract

Geomorphological mapping is essential for identifying landforms, determining erosion, and reconstructing the morphological evolution over time. The relative chronology between features can be established, supporting the study of the potential hazard and associated risks in volcanic terrains. Geomorphological analysis, performed on a 12.5 m ALOS PALSAR DEM, along with field-work and new K–Ar geochronological data, help to clarify the overall evolution of the Cerro Bravo volcano. The observed north-south arrangement of the craters, the stratigraphic relationships, and the new K–Ar ages reveal that the volcanic activity migrated towards the north, with the younger activity concentrated north of the volcanic area. This evolution, which occurred from the Middle Pleistocene to the Holocene, is evidenced by four consecutive semicircular crater-like structures associated with four building stages. Effusive and explosive activity was observed in all recorded volcanic activity stages, indicating a consistent volcanological behavior of this volcano over time, characterized by a bimodal effusive-explosive eruption style. The effusive activity involved lava domes and lava flows, while the explosive activity included dome collapses and Plinian eruptions. This morphological study can help assess the geological risk and potential hazards of inaccessible areas.