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Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Numerous slides, rock falls and flows occur in the arid mountainous areas of northwestern Argentina. On 10 January 2017, torrential rain caused the acceleration of large-scale and slow-moving landslides mainly in the Los Filtros basin and it produces important damage in the Volcán village causing fatalities, dozens of evacuees and great economic losses, with the total destruction of buildings, services and infrastructure. However, in the two adjacent creek basins, the Coiruro basin to the north and Del Medio basin to the south, the effects were smaller. A morphometric analysis of these three adjacent basins was carried out in order to understand this catastrophic event and to explore its causes. The geological characteristics of the study basins are very favourable conditioning factors in landslide generation. Precambrian-age low grade metaclastics shatter in the frost climate of the higher mountains and poorly consolidated Quaternary deposits along the sides of the gully erode readily and become source material for landslides. Also, the area, shape, relief and slope of the basins would have been other key factors in the debris/mud flow generation in the Los Filtros creek basin. The Melton ratio number has been a key morphometric index to discriminate river basins susceptible to different types of flows. Finally, this study aims to increase knowledge of all the above-mentioned events in order to provide several methods of analysis for landslide prevention and control in adjacent basins whit different dynamics in the Central Andes. [ABSTRACT FROM AUTHOR]

Slides, rockfalls, debris floods and debris flows are periodical events in the dry mountainous regions of Argentina, during times of torrential rainfalls. In the Grande River basin, Jujuy Province, these processes take place almost every summer. Extreme rainfall on January 10, 2017 caused the seasonal acceleration of large-scale and slow-moving landslides in the Los Filtros River basin. These slides broke down into a disaggregated mass, triggering a debris flow which transformed progressively downstream into a debris flood, producing widespread damage along a narrow valley (named Quebrada de Humahuaca), with the Volcán village withstanding the worst of the disaster. The event caused four fatalities and great economic losses, mainly destroying infrastructure and buildings. In order to document this catastrophic event and to explore its causes, a morphometric analysis of the Los Filtros river basin, tributary of the western margin of the Grande River and located on the Cordillera Oriental area, was carried out. The drainage network was derived from digital elevation models. In addition, some landslides were mapped using high-resolution satellite data acquired before and after the event. Of a total landslide area of 2.39 km², 0.60 km² was considered as active and 0.089 km² as new sliding area (from 2015 to 2017) associated to the large-scale and slow-moving landslides. The geological characteristics of the study basin are very favourable conditioning factors in landslide generation. Precambrian-age low grade metaclastics shatter in the frost climate of the higher mountains and poorly consolidated Quaternary deposits along the sides of the gully erode readily and become source material for landslide that damage or bury roads, railroads, and houses. Finally, this study aims to increase knowledge of all the above-mentioned events in order to provide several methods of analysis for landslide prevention and control. [ABSTRACT FROM AUTHOR]

Flash floods occur periodically in the hilly areas of Argentina but since they generally occur at inhabited areas, these are rarely registered. Several factors contribute to the occurrence of flash floods: heavy seasonal rains, rugged topography and geological structures. On Thursday night 23 January 2014 an extreme rainfall event took place in El Rodeo, Catamarca Province, triggering an unexpected flash flood. This flood caused 14 fatalities and great economic losses in the main localities of the Ambato Department. Steep slope gradients facilitated the quick drainage of the precipitated volumes. Water, boulders and debris channeled downstream caused severe stream bank erosion and major damage to houses roads and bridges. This paper presents a morphometric analysis in order to determine some geomorphic characteristics of the Ambato River basin together with a preliminary analysis of the flood hazard potentially damaging to inhabitants and infrastructure to downstream villages. The study was carried out using high-resolution satellite data acquired before and after the event. The drainage networks were derived from Aster GDEM V2 and satellite images. [ABSTRACT FROM AUTHOR]

A large (>0.1 km 2 ) and complex mass movement in the Central Andes of Argentina (final portion of Cordillera de Olivares, Frontal Cordillera), was studied to identify the triggering factors and understand their relationship with geomorphic, cryogenic and climatic dynamics. This debris-rockslide is composed of clast supported blocks of Permian–Triassic volcanic breccias. In order to characterize this feature, high resolution satellite imagery interpretation was carried out, together with the study of the landslide detachment zones and landslide bodies. These debris-rockslide events could have originated as a consequence of the combination of internal slow deformation and fragmentation under periglacial conditions, followed by a sudden collapse of the rock mass. Pre- and post-slide digital elevation models (DEMs) were created from topographical data with the help of a Geographic Information System (GIS) tool. Approximately 14.89 M m 3 of rock and debris travelled nearly 2 km from an elevation of 5023 m–4325 m asl. Although usually the origin of such catastrophic movements is related to seismically active areas with earthquakes whose magnitude frequently exceed Ms 6, our hypothesis is that this debris-rockslide event has a climatic origin caused by large snow accumulations during winters and subsequent fast meltdown processes during spring, which would have facilitated the sliding. The paper outlines the important role that snowmelt can play in the genesis and evolution of rock displacements and the importance of meteorological data, seismic catalogues, historical aerial photography and satellite images in geomorphological back-analysis. [ABSTRACT FROM AUTHOR]

This study employs statistical modeling techniques and geomorphological mapping to analyze the distribution of debris-rockslides in relation to altitude, aspect, slope angle, lithology and distance to lineaments using optical remote sensing techniques with GIS. The study area includes a portion of the Central Precordillera of San Juan around 32°S, 69°W, where few geomorphological studies have been conducted. A debris-rockslides inventory map was prepared using debris-rockslides locations identified from satellite imageries, a total of 35 debris-rockslides were identified in an area of 288.13 km 2 (with a total slide area of 6.36 km 2 ). All of the debris-rockslides were rotational slides, affecting Upper Ordovician and Upper Devonian deposits. The volumes of debris-rockslides were estimated using the sloping local base level technique that allows computing the possible pre-rockslide topography and the bedrock–deposits interface. The relationship between the variables and the slide distribution was analyzed using the frequency ratio method and logistic regression models. The analytical results show that lithology and slope exert major influences. Lithology is found to be the most important aspect in the study area. [ABSTRACT FROM AUTHOR]

In this paper we evaluate hydrological aspects of the Seco River basin and the relationship with damages that occurred in the town of Los Berros, south of the city of San Juan, in the Sarmiento department, during the torrential rains of January 2013. One of the main geological hazards that affect the Sarmiento department is flash floods, produced by heavy seasonal rains, characterized by their high velocities and destructive power Several morphometric characteristics of the basin are analyzed and some basic parameters (area, perimeter, length, altitude and slope of the main channel, etc.) are calculated. These calculations are the basis for roughly predicting the behavior of the basin in the presence of torrential rainfall, resulting in large volumes of water with peak lows capable of generating significant floods. On the basis of the January 2013 rainfall (84 mm/h), the estimated peak lows demonstrated the basin behavior, which during the exceptional rainfalls becomes a potentially dangerous area with high levels of destruction. Furthermore, a description is included of the landforms identified in the drainage basin, whose axes are the eastern piedmont of the Loma Redonda and the cerro Pedernal de Los Berros. The study allowed explanation of the relief features of the region and recognition of several geomorphological units generated by various geomorphic processes that have determined the complex nature of the regional landscape. [ABSTRACT FROM AUTHOR]

Abstract: The Dry Andes of the Cordillera Frontal of San Juan (30°S latitude) is characterized by high relief with peaks up to 5000ma.s.l. This geological province is mainly made up of a suite of Triassic to Miocene volcanic rocks. Modern ice glaciers are small and few in number, and persistent snow fields are similarly small and scattered. The predominant landforms in these areas have been shaped in a periglacial environment superimposed on an earlier glacial landscape. A preliminary inventory map of rock glaciers was constructed using optical remote sensing techniques, digital topographic analysis and aerial photograph data organized in a geographic information system (GIS). Over 140 rock glaciers have been identified: 90% are active or inactive and the rest are fossil. A total of 88 rock glaciers are considered active. The most common periglacial features recognized in the area are talus glaciers, and only 23% are tongue-shaped glaciers. [Copyright &y& Elsevier]

• Lithology is an important related factor in the debris flow occurrence in the area. • Fifteen debris flows-related factors were applied to debris flow susceptibility. • All flow tracks and geometrical interval has higher prediction accuracy. • The methodology is easy to reproduce and applied to other mountainous regions. Debris flow and floods represent one of the main natural hazards that impact transport infrastructure, causing serious damage, economic losses and hinder regional economic development. These processes are eventually associated with massive traffic cuts and direct damage to road structures. To enable the prevention of such consequences, this paper employs statistical modeling techniques, various instability factors and geomorphological mapping to generate debris flow susceptibility maps in a portion of an important route on the Dry Andes of San Juan in the Agua Negra River basin, Argentina. A debris flows inventory map was prepared using satellite images and field checks. The debris flows inventory was randomly divided into a model dataset 80% (47 debris flows) and remaining 20% (12 debris flows) data was used for validation purpose. The instability factors chosen that influence debris flows occurrence were: elevation, slope angle, slope aspect, solar radiation, topographic wetness index, stream power index, topographic position index, Melton ruggedness number, terrain ruggedness index, sediment transport capacity index, plan curvature, profile curvature, lithology, distance to road and proximity to stream. Using these factors, six different models of debris flow susceptibility were calculated by Frequency ratio (Fr). Lithology (igneous complex) was found to be important debris flows-related factor in the study area. The precision of the results was evaluated by receiver operating characteristic (ROC) analysis. According to the area under the curve (AUC) the models of all flow track and natural breaks and all flow track and geometrical interval were 0.83 and 0.84, respectively, showing a practically identical predictive capacity. [ABSTRACT FROM AUTHOR]