Browsing by Author "Maringue Canales, José Ignacio"

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    Amenaza sísmica en Mejillones mediante una aproximación geofísica : análisis dinámico y amplificación sísmica asociada.
    (2017) Maringue Canales, José Ignacio; Yáñez Carrizo, Gonzalo Alejandro; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    La Península de Mejillones, ubicada en el norte de Chile, representa un sitio de interés en términos de peligro sísmico debido a una ‘laguna’ sísmica de aproximadamente 100 años en la zona, los grandes efectos de sitio potenciales, y la presencia del puerto más importante en la región de Antofagasta. Además, el borde oeste de la Pampa de Mejillones está limitado por la Falla de Mejillones, la cual controla el desarrollo de la Cuenca del mismo nombre hacia el este. En este trabajo, se realizó una caracterización dinámica de la porción norte de la cuenca usando una modelación integrada de observaciones geofísicas. Estas observaciones fueron: método gravimétrico, método magnetotelúrico (MT), y análisis de dispersión de ondas superficiales. Los resultados de la campaña geofísica muestran espesores de suelo de hasta 750 metros en la zona más profunda, con pendientes más fuertes hacia el Oeste, y variaciones más suaves hacia el Este, en concordancia con una geometría de cuenca del tipo hemi-graben asociada a una falla normal. El estrato sedimentario está caracterizado por velocidades de onda de corte entre 300 y 700 m/s, resistividades eléctricas extremadamente bajas (inferiores a 1 ohm-m) y densidades de entre 1.4 a 1.8 gr/cm3. La interpretación integrada permitió generar un modelo espacial y petrofísico de la cuenca de Mejillones, a partir del cual se estudia el comportamiento sísmico del lugar. Resultados preliminares del análisis dinámico inelástico (mediante el método de Elementos Espectrales) muestran aceleraciones en superficie de hasta un 100% superior a la solicitación, evidenciando posibles amplificaciones significativas en superficie ante movimientos sísmicos. Estos efectos se hacen más importantes en la porción centro-oeste (zona más profunda). Hacia los extremos, las amplitudes disminuyen junto con la disminución de la columna de suelo.
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    Unravelling geological controls on groundwater flow and surface water-groundwater interaction in mountain systems: A multi-disciplinary approach
    (ELSEVIER, 2023) Marti, Etienne Bernard Christian; Leray, Sarah Tiphaine Lucile; Villela, Daniela; Maringue Canales, José Ignacio; Yañez Morroni, Gonzalo José; Salazar, Esteban; Poblete, Fernando; Jiménez, Jose; Reyes, Gabriela; Poblete Farias, Guillermo Hernán; Huaman Sevilla, Zeidy Lisseth; Figueroa González, Ronny Javier; Araya Vargas, Jaime Andrés; Sanhueza, Jorge; Muñoz, Marjorie; Charrier, Reynaldo; Fernández, Gabriel
    Mountain water resources are considered to be the world's water towers. Still, despite their importance for downstream societies and ecosystems and their vulnerability to climate change, they remain poorly understood - It is the case in particular of mountain groundwater systems. Their complexity makes them difficult to conceptualize, while their remoteness makes them difficult to study, both observationally and instrumentally. Understanding mountain hydrogeological systems is mostly limited by the lack of characterization of the subsurface geologic framework and by the limited understanding of the role of geological structures on groundwater flow and on surface water-groundwater interaction. Removing methodological barriers is therefore a necessary step for improving the understanding of mountain hydrogeological systems. To tackle this problem, we develop a comprehensive multi-disciplinary approach to gain insights into the hydrogeological role of geological structures in ungauged mountain catchments. The methodology consists of several complementary methods: (1) geological mapping at multiple scales; (2) a geophysical study including on ground Electrical Resistivity Tomography (ERT) and, gravimetry transects, and a UAV-based magnetic survey; (3) hydraulic data, including a 9 km long transect of streamflow measurements in the recession period, the longterm Normalized Difference Vegetation Index (NDVI), and varied hydric markers (e.g., a thermal spring and a puddle). The methodology is tested in the Parque Nacional del Rio Clarillo, an ungauged catchment in the Andes Mountains (& AP;130 km2) that is illustrative of the complexity of mountain hydrosystems featuring fault zones, weathered zones, intrusive rocks, and volcano-sedimentary successions.An increase of approximately 50% in the streamflow is observed over a short distance of 1 km. Such a localized and significant increase in the baseflow is not related to any superficial supply and can only be explained by groundwater exfiltration. Based on the multiscale geological mapping and geophysical survey, a regional N-S fault and a secondary set of E-W local faults are identified in the vicinity of the resurgence area, which conjointly are likely to export groundwater from a neighbouring subcatchment up to the resurgence area. Downstream of the resurgence area, no significant change in the baseflow is observed, corresponding to the presence of an impermeable granitic pluton identified by the geological and geophysical mapping. Finally, a fractured zone in the Andean foothills is identified in the volcanic unit, which coincides with a perennial thermal spring, indicating upwelling flow and hydrogeological connectivity between the mountain block and the alluvial basin.The results strongly support the ability of the proposed methodology to identify geological structures that substantially impact the evolution of the baseflow through the catchment. The complementary multi-disciplinary methods are used innovatively to infer the link between geological and hydrogeological structures. The methodology does not aim to fully characterize the geological framework of the catchment but pragmatically focuses on hydrogeologically pertinent structures that may impact baseflow and consequently catchment management.