Search

The dataset compiles high-resolution imagery of landform features of the SW flank of the Doña Juana Volcanic Complex, Colombia. Images were acquired with an unmanned airborne vehicle during June, 2018, using two DJI quadcopter Phantom 4 Pro, equipped with a 20 MP camera. We captured 4575 NADIR images with an approximated height of 120m above ground level and a 70% overlap. We performed 20 flights, which covered a top-down elevation difference of ~900 m and a 5.5 km along the Humadal Creek length. Measurements were staggered, considering the significant altitude differences along the creek. Information includesa digital terrainmodel (DTM) with a 4.7cm ground sampling distance (GSD).

La reactivación de volcán Nevado del Huila en el 2007 y actividad posterior, han dado lugar a la formación de grietas a gran escala en la cima, pequeñas emisiones de ceniza, emisión continua de lodo en octubre - noviembre de 2008, generación de importantes lahares, destacándose los generados el 18 de abril de 2007 y el 20 de noviembre de 2008, en los cuales hubo un aporte de 10 y 77 millones de m³ de agua respectivamente, a la Represa de Betania, cantidad muy superior a la generada por la fusión de hielo-nieve debida a la actividad y, como fase magmática, la extrusión de domos coalescentes en el flanco SW del Pico Central en 2007 y 2008. Análisis de cenizas emitidas durante las actividades eruptivas se caracterizan por presentar en cantidad variable minerales de origen hidrotermal tales como cuarzo, sílice, feldespato, pirita, alunita, anhidrita, yeso, clorita, muscovita, esmectita, caolinita e ilmenita, mientras que el material juvenil es muy poco o ausente. Este hecho, así como el volumen inusual del agua involucrada en la generación de los lahares indicarían que, a excepción de los domos, el material emitido por el volcán Nevado del Huila, está asociado a eventos de actividad freática, debida a la interacción de fluidos y gases magmáticos con agua proveniente de acuíferos superficiales y posiblemente reservorio hidrotermal bajo el edificio volcánico. Los resultados de los análisis de cenizas emitidas así como los de sedimentos, aguas y precipitados en el rio Páez, sustentan esta hipótesis. The reactivation of the Nevado del Huila volcano in 2007 and subsequent activity, led to the formation of large cracks at the top, small emissions of ash and continuous emissions of mud in October-November 2008. There were also major lahars, notably those generated on April 18 2007 and on November 20 2008 in where an excess of 10 and 77 million m³ of water respectively, was repported in Betania Reservoir (which was substantially higher than the water that could be generated by the fusion of ice-snow due to the activity). Magmatic episode led to the extrusion of coalescent domes in the SW flank of Pico Central in 2007 and 2008. Analysis of emitted ash during the eruptive episodes are characterized by varying amounts of hydrothermal mineral such as quartz, silica, feldspar, pyrite, alunite, anhydrite, gypsum, chlorite, muscovite, smectite, kaolinite and ilmenite, while the juvenile material is few or absent. These facts and the unusual volume of water involved in the generation of lahars indicate that, except for the domes, the material emitted by the volcano Nevado del Huila are associated to phreatic activity due to the interaction of fluids and magmatic gases with water from shallow aquifers and possibly with a hydrothermal reservoir beneath the volcano. The results of the analysis of ash as well as sediment, water and precipitates taken from the Páez River support this hypothesis.

El basamento del Altiplano Nariñense está conformado por rocas de los grupos Diabásico yDagua de edad Cretácica, las cuales están suprayacidas por depósitos volcanoclásticos aflorantescomo ignimbritas, lavas y depósitos piroclásticos del Neógeno Superior – Holoceno, provenientesesencialmente de los complejos volcánicos del Azufral, Cumbal, Chiles-Cerro Negro, Pajablanca yalgunos volcanes de la Cordillera Real Ecuatoriana.Este trabajo presenta la descripción litológica y análisis estratigráfico de los depósitos volcánicos apartir del levantamiento de 880 m distribuidos en nueve (9) columnas estratigráficas en afloramientoslocalizados en los municipios de Ipiales, Guachucal, Carlosama, Ospina y Túquerres. En generalse interpretan cinco secuencias con distintas características litológicas, las cuales presentan unadistribución regional a pesar de los cambios laterales producto de la actividad antigua y reciente delos diversos centros eruptivos.

We present the Dona Juana Volcanic Complex (DJVC) geological map, stratigraphy, Ar/Ar-and-C14 geochronology resulting from a pilot-mapping project in Colombia, as a study-case for the application of modern, international volcano geology techniques in low-latitude environments. Lithostratigraphy and lithofacies analysis (for description of rock bodies and mapping), lithosomes (for the definition of eruptive centres) and unconformity-bounded units (for stratigraphic correlation), as well as new geochronological data and the interpretation of eruption units were successfully integrated. The geological mapping and stratigraphic analysis provided an effective representation of the volcanic edifices/vents that make up the DJVC, so that we could reconstruct the geological evolution from the time and spatial distribution of the corresponding volcanic products and the range of lithofacies associations. The geological database and the forthcoming interpretation in terms of eruption behaviour establish the basis for realistic long-term hazard assessment. The DJVC is a calc-alkaline dacitic volcanic complex within the Central Cordillera of Colombia, which started its activity about 1125.4 ± 4.4 ka ago. It comprises three spatially overlapping edifices and three adventive cones, which unconformably overlay Lower Cretaceous metasedimentary and metavolcanic rocks of oceanic origin. Each of the three overlapping edifices is truncated at the summit by a volcano-tectonic depression, without identifiable caldera-forming products. Two of these volcano-tectonic features display important proximal unconformities and, together with their correlative disconformities and paleosols, indicate significant quiescences of volcanic activity. The Holocene record has been mostly characterized by the emission of three lava-dome fields infilling the youngest volcano-tectonic depression and interrupting the corresponding unconformity. These lava domes have recurrently collapsed to originate block-and-ash flows followed by vulcanian explosions producing pyroclastic density currents and lahars. The corresponding eruptive products have drained along the present river basins to the NE and SW of DJVC, forming depositional terraces currently populated by nearly 49,000 rural and urban inhabitants.