DInSAR for a Regional Inventory of Active Rock Glaciers in the Dry Andes Mountains of Argentina and Chile with Sentinel-1 Data

The Dry Andes region of Argentina and Chile is characterized by a highly developed periglacial environment. In these arid or semi-arid regions, rock glaciers represent one of the main pieces of evidence of mountain creeping permafrost and water reserves in a solid state. However, their distribution, degree of activity, and response to global warming are not yet well understood. In this context, this work aims to show the potential of the Sentinel-1-based interferometric technique (DInSAR) to map active rock glaciers at a regional level. In particular, the paper presents an active rock glacier inventory for the study area, which covers approximately 40,000 km2, ranging from latitude 30°210S to 33°210S. A total of 2116 active rock glaciers have been detected, and their elevations show a high correlation with the west-east direction. This result was obtained by using only 16 interferometric pairs. Compared to other remote sensing classification techniques, the interferometric technique offers a means to measure surface displacement (active rock glacier). This results in a reliable classification of the degree of activity compared to other methods, based on geomorphological, geomorphometric, and/or ecological criteria. This work presents evidence of this aspect by comparing the obtained results with existing optical data-based inventories. We conclude that the combination of both types of sensors (radar and optical) is an appropriate procedure for active rock glacier inventories, as both mapping methodologies are complementary.Fil: Villarroel, Cristian Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geología; ArgentinaFil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario; ArgentinaFil: Forte, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Monserrat, Oriol. Agencia Espacial Europea; EspañaFil: Morvillo, Mónica Cristina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentin

Assessment of ground deformation and seismicity in two areas of intense hydrocarbon production in the Argentinian Patagonia

The exploitation of both conventional and unconventional hydrocarbons may lead to still not well-known environmental consequences such as ground deformation and induced/triggered seismicity. Identifying and characterizing these effects is fundamental for prevention or mitigation purposes, especially when they impact populated areas. Two case studies of such effects on hydrocarbon-producing basins in Argentina, the Neuquén and the Golfo de San Jorge, are presented in this work. The intense hydrocarbon production activities in recent years and their potential link with the occurrence of two earthquakes of magnitude 4.9 and 5 near the operating well fields is assessed. A joint analysis of satellite radar interferometry and records of fluid injection and extraction demonstrate that, between 2017 and 2020, vertical ground displacements occurred in both study areas over active well fields that might indicate a correlation to hydrocarbon production activities. Coseismic deformation models of the two earthquakes constrain source depths to less than 2 km. The absence of seismicity before the beginning of the hydrocarbon activities in both areas, and the occurrence of the two largest and shallow earthquakes in the vicinity of the active well fields just after intensive production periods, points towards the potential association between both phenomena.Fil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Grosso Heredia, Javier A.. Universidad Nacional del Comahue; ArgentinaFil: Béjar Pizarro, Marta. Instituto Geológico y Minero de España; EspañaFil: Pérez López, Raúl. Instituto Geológico y Minero de España; EspañaFil: Portela, Juan. Universidad Politécnica de Madrid; EspañaFil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Monserrat, Oriol. Centre Tecnològic de Telecomunicacions de Catalunya; Españ

Magnitudes y características de los procesos geodinámicos en el ambiente glacial y periglacial del Cordón de la Ramada (Andes Centrales argentinos) mediante técnicas de teledetección

La investigación lleva a cabo la medición de los cambios en superficie (geodinámica) de las distintas formaciones crío y glaciogénicas de los ambientes glacial y periglacial del Cordón de la Ramada en los Andes Centrales argentinos. Conocer la evolución en las últimas décadas de este ambiente permite estimar su estado de conservación o deterioro, haciendo posible evaluar el impacto del calentamiento global o de la actividad antrópica a escala local. Las mediciones se han llevado a cabo con fotogrametría e interferometría SAR, a las que se ha dado soporte con trabajo de campo. En el primer caso con datos de sensores analógicos aerotransportados de la década del sesenta y con imagen satelital contemporánea de alta resolución (SPOT 6 y 7). Y para el segundo caso, con datos de la misión Sentinel-1 de la ESA. En las campañas de campo se efectuaron mediciones geodésicas GNSS de puntos de apoyo fotogramétrico. Mediante estas técnicas ha sido posible: A) identificar los fenómenos de movimiento en la región y establecer sus características en tres dimensiones mediante DInSAR, B) establecer campos de vectores de velocidad de los desplazamientos en planimetría para los glaciares mediante técnicas de correlación de imágenes, y finalmente, C) generar dos DEM de alta resolución con cincuenta años de lapso cronológico entre si para realizar balance de masas geodésico.Atendiendo a los resultados se expone un análisis cuantitativo y cualitativo, permitiendo tanto visualizar las características de los movimientos como evaluar las dificultades e idoneidad en la aplicación de los métodos para los objetivos propuestos. La aproximación al objeto de estudio se realiza desde una escala geográfica media. Es habitual encontrar casos de estudio muy detallados circunscritos a fenómenos particulares como por ejemplo el estudio de un solo glaciar. O por el contrario muy amplios, como grandes inventarios regionales que exponen variables genéricas como modelos climáticos o de distribución espacial de permafrost. Menos habituales son los trabajos que abordan la temática desde unidades geográficas intermedias que permite manejar niveles de precisión de detalle, a la vez que realizar una interpretación en términos regionales. Se describe de este modo por primera vez en forma detallada y de modo sistemático el ambiente glacial y periglacial de la Ramada, permitiendo una mejor comprensión de su dinámica y evolución.The aim of the research was to carry out the measurement of changes in surface (geodynamic) of the different cryo and glaciogenic formations of the glacial and periglacial environments of the Cordon de la Ramada in the Argentine Central Andes. Knowing the evolution of this environment in the last decades allows to estimate its state of conservation or deterioration, making possible to evaluate the impact of global warming or anthropogenic activity at the local scale. The measurements were carried out with photogrammetry and SAR interferometry, which have been supported with field work. For the first case, with data from airborne analogue sensors of the sixties and with contemporary high-resolution satellite image (SPOT 6 and 7). For the second case, with data from the ESA Sentinel-1 mission. In the field campaigns, GNSS geodetic measurements of ground control points for photogrammetric purposes were made. Through these techniques it has been possible to: a) identify the dynamical phenomena in the region and establish its three dimensional characteristics through DInSAR; b) establish vector velocity vector fields in planimetry for the glaciers using image correlation techniques; and finally, c) generate two high-resolution DEMs with fifty years of chronological time-lapse between them to perform geodetic mass balance. Based on the results, a quantitative and qualitative analysis is presented, allowing for both the visualization of the characteristics of the movements and the evaluation of the difficulties and suitability in the application of the methods for the proposed objectives. The approximation to the object of study is presented from a medium geographic scale point of view. Usually it is possible to find either very detailed study cases circumscribed to a particular phenomenon such as the study of a single glacier, or research with broad scope, such as large regional inventories that expose generic variables like climate models or permafrost spatial distribution. Researches that approaches the subject from intermediate geographical units, whose allows for handling levels of detail precision, while also performing an interpretation in regional terms, are less common. In this way, the glacial and periglacial environment of the Cordon de la Ramada is described here for the first time in a very detailed and systematic manner, allowing a better understanding of its dynamics and evolution. The approach to the subject is developed following the most recent methods applied to this type of study.Fil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentin

High resolution SPOT DEM over large areas in central and south Andes and observations on the 2018 Perito Moreno glacial lake outburst flood

This study describes the use of multi-temporal SPOT 6 and 7 tri-stereo images for producing high resolution (3 × 3 m pixel) digital elevation models (DEM) over two large (2680 and 837 km2) mountainous and glaciated regions in the Argentinian Andes. The images were radiometrically adjusted to enhance matching over different light intensity conditions, allowing for photogrammetric reconstruction in zones of both poor texture and chromatic contrast. Independent point clouds were obtained from every image pair and contrast adjustment, and then merged into a single point cloud, which was cleaned from noisy points by an iterative filtering process. The first testing place, the Cordón de la Ramada massif, is in the Central Andes, an arid area with one of the highest density of rock glaciers in the world and some of the highest peaks of the Americas. The second is in the Parque Nacional Los Glaciares in the Southern Andes, host of the notorious Perito Moreno glacier which ends in the Lago Argentino, forming cyclical ice-dams with a consequent downstream flooding after dam-break. This work provides 1) a practical application to generate high resolution DEM from SPOT 6 and 7 tri-stereo images, 2) the first high resolution DEM over Cordón de la Ramada and Perito Moreno glacier, and 3) the March 2018 preand postice-dam break DEM for the Perito Moreno glacier, which provides the opportunity to describe this glacial lake outburst flood.Questo studio illustra l’utilizzo di immagini tri-stereo multi-temporali SPOT 6 e 7 per modelli altimetrici digitali (DEM) di alta risoluzione (3 × 3 m pixel) di due vaste regioni (2680 e 837 km2) montuose glacializzate nelle Ande argentine. Le immagini sono state radiometricamente modificate per incrementare le corrispondenze fra punti in diverse condizioni di intensità di luce, rendendo possibile una ricostruzione fotogrammetrica in zone di scarso contrasto sia di tessitura che cromatico. Sono state ottenute nuvole di punti indipendenti per ogni coppia di immagini e modifica di contrasto, poi successivamente unite in un’unica nuvola di punti dalla quale sono stati eliminati punti erroneamente proiettati attraverso un processo di filtraggio iterativo. La prima area test, il Cordón de la Ramada, si trova nelle Ande centrali, e consiste in un’area arida con una delle più alte densità di rock glacier nel mondo, oltre alla presenza delle cime più alte delle Americhe. La seconda area test è collocata nel “Parque Nacional Los Glaciares” nelle Ande Meridionali, dove si trova il famoso Ghiacciaio Perito Moreno che termina nel Lago Argentino formando sbarramenti temporanei e conseguenti onde di piena a seguito del loro collasso. Questo lavoro fornisce a) un’applicazione pratica per la generazione di DEM ad alta risoluzione da immagini tri-stereo SPOT 6 e 7, b) il primo DEM di alta risoluzione del Cordón de la Ramada e del Ghiacciaio Perito Moreno e c) i DEM del Marzo 2018, pre e post collasso dello sbarramento glaciale del Perito Moreno, fornendo elementi utili per descrivere il fenomeno di esondazione che ne è conseguito.Fil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Roberti, G.. No especifíca

Active layer and permafrost thickness in rock glaciers derived from geophysical methods in the semiarid Andes of Argentina

The Argentinean Central Andes region (31°S to 35°S) exhibits one of the largest densities of rock glaciers on Earth. However, few studies have focused on the knowledge of the internal structure of these landforms. In the present paper, a characterization of the internal structure of two rock glaciers has been achieved by using Seismic Refraction Tomography and Vertical Electrical Sounding. In one of the rock glaciers, the thickness of the active layer is quite homogeneous, while in the other said thickness diminishes towards the front. In both rock glaciers, near the top of the active layer, the P-wave velocity values vary between 350 and 600 m/s, while in the bottom of the layer the P-values range from 800 to 1700 m/s. As regards the permafrost layer, it shows an irregular thickness with values varying between 4 and 27 m approximately. In addition, P-wave values ranging from 1600 to 3300 m/s and a few kΩm values of electrical resistivity have been recorded. The increase of geophysical surveys in rock glaciers in the Andes region is expected to give a better understanding of the characteristics, distribution and origin of the ice present in these landforms. It should also allow researchers to estimate with certainty their ice content as solid-state reserves.Fil: Villarroel, Cristian Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Forte, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Ortiz, Diana Agostina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Güell, Arturo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentin

Internal structure of a large, complex rock glacier and its significance in hydrological and dynamic behavior: A case study in the semi-arid Andes of Argentina

This paper presents an analysis of the internal structure, hydrogeology and dynamics of a large, complex, multilobate and multiroot rock glacier combining electrical resistivity tomography (ERT), hydrochemical data and differential interferometry synthetic aperture radar (DInSAR). The rock glacier consists of a series of overlapping lobes that represent different advancing stages with different degrees of conservation. The ERT surveys characterize the active layer and the upper part of the permafrost layer, the latter showing a heterogeneous geometry and electrical resistivity values ranging from 7 to 142 kΩm. Hydrochemical data argue for both the existence of different disconnected water flow pathways inside the rock glacier and the remarkable ionic concentrator effect of this landform. The horizontal displacement from October 2014 to April 2017 shows greatest magnitudes in the upper sector of both tongues, reaching speeds of up to 150 cm/year. The active frontal sector shows a displacement rate of 2–4.5 cm/year. This study contributes to knowledge of the material properties of rock glaciers, which are considered to represent important reservoirs/water resources, and their influence on the distribution of mountain permafrost, hydrology, and dynamics. Finally, to the best of our knowledge, the possible influence of the metal content of the ground on the resistivity values recorded for mountain permafrost is highlighted for the first time.Fil: Villarroel, Cristian Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Ortiz, Diana Agostina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina. Universitat Bonn; AlemaniaFil: Forte, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Tamburini Beliveau, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Ponce, Oscar David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Imhof, Armando Luis. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; ArgentinaFil: López, Andrés. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentin