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Cerro Overo maar and La Albóndiga lava dome are two independent monogenetic volcanoes located in the Central Volcanic Zone of the Andes in northern Chile, close to the active Lascar and Chiliques volcanoes. Cerro Overo maar was formed <77 ka ago by explosive-effusive eruptions, including phreatomagmatic activity, while La Albóndiga lava dome (Pleistocene) is the result of magmatic explosive-effusive activity alone. Cerro Overo and La Albóndiga are characterized by deposits composed of pyroclastic rocks and dense coherent lava blocks. At Cerro Overo, these deposits are located around the crater rim, while at La Albóndiga, they form coherent in situ lava dome features. Cerro Overo also displays thin ash- and lapilli-dominated deposit layers presumed to be pyroclastic surge deposits, which include juvenile pyroclasts exhibiting cauliflower textures, numerous exotic accidental lithics, and ballistically transported lapilli, bombs, blocks, and bomb sags. These fragments include recycled, juvenile pyroclasts, as well as material from older volcanic and intrusive rocks from the stratigraphic units immediately below. These small-volume volcanoes represent two of the less silicic volcanoes (~54 wt.% SiO2) in the northern Chilean Pleistocene to Holocene volcanic provinces. They are characterized by a fine grain size (mainly fine lapilli), olivine phenocrysts with skeletal textures, ignimbritic, dioritic, and granitic xenoliths, and quartz xenocrysts, with high concentrations of incompatible trace elements and light rare earth elements. The general magmatic evolution of the Cerro Overo and La Albóndiga systems has been controlled by fast ascent (e.g., skeletal olivine phenocrysts) of mantle-derived magma associated with mixing, fractional crystallization, and a low degree of crustal assimilation during turbulent ascent processes. Such eruptions provide evidence that various factors play an essential role in the transition from explosive-effusive magmatic (Cerro Overo and La Albóndiga) to phreatomagmatic (Cerro Overo) volcanic eruption styles. [ABSTRACT FROM AUTHOR]

Monogenetic volcanoes are small-volume landforms (< 1 km3) which can develop complex eruption histories. Their genesis may include variations in their primary magma sources and petrogenetic evolution, eruption styles transitions, changes in their emplacement conditions. The Central Andes (Northern Chile) contains >900 small-volume volcanoes, most of which lack a detailed knowledge of their eruption histories due to the limited volcanological studies available. In this paper, we present a detailed volcanostratigraphic, morphometric and petrologic study are used to reconstruct the geology and eruptive history of Cerro Negro volcano. It is a Pleistocene pyroclastic cone which stands out from all monogenetic volcanoes of this region due to its larger size (~1 km3) and location along the axis of the orogen. The activity of Cerro Negro began with a phreatomagmatic phase that produced breccias and a lithic-rich tuff, followed by magmatic activity with lava fountaining and Strombolian styles. This latter magmatic phase produced short lava flows, but mostly spatter agglutination and tephra fallout layers. The composition of erupted materials spans from calk-alkaline basaltic andesite to dacite. The least evolved magmas of Cerro Negro are derived from mantle wedge's partial melts without significant crustal assimilation. However, changes in the composition through the eruption suggest crystal fractionation and shallow magma storage, followed by mixing and crustal contamination during the late stage of the eruption. The absence of significant repose period between the deposition of the distinct products and their total volume together with the observed compositional variations imply that Cerro Negro represents a large volume polycyclic monogenetic volcano. These results are important to understand the mafic magma evolution in thickened crusts and the eruptive styles of long-lasting monogenetic eruptions. • Cerro Negro (CNV) is a c. 1 km3 (bulk volume) Pleistocene pyroclastic cone; it classifies as a large monogenetic volcano • CNV erupted in successive phreatomagmatic, lava fountaining and Strombolian phases; the eruption may have lasted years • CNV magmas were calk-alkaline (55.1 to 66.5 wt% SiO 2) and became more silicic as the eruption progressed • Magmas sourced from metasomatized spinel peridotite; polymagmatism involving fractionation, crustal assimilation and mixing [ABSTRACT FROM AUTHOR]

The Negros de Aras monogenetic volcanic field in the Central Volcanic Zone of the Andes displays the highest concentration of scoria cones in northern Chile (0.23 per km2). It contains 66 vents, 22 of which are emission points of lava flows without an associated recognizable volcanic edifice, whereas 44 are typical scoria cones. Most vents are associated with basaltic andesite and andesite lava flows of up to 4.6 km in length. A few scoria cones show signs of either initial or final phreatomagmatic eruptions recorded in their pyroclastic successions. A geomorphological, morphometric, and spatial distribution analysis of the scoria cones of this volcanic field was carried out with the purpose of identifying the factors and processes that governed their emplacement, growth, and final morphology. The morphometric analysis was performed on 16 well-delimited scoria cones applying the MORVOLC algorithm using the TanDEM-X 12 m resolution digital elevation model. Analysis of the distribution and elongation of the craters of the scoria cones defines four alignments inferred to be related to the local and regional structural elements of the area. Volcanic activity seems to have been related to a N-S fault system with an E-W maximum stress orientation, favoring magma ascent and scoria cone emplacement following inherited fractures in these preferential orientations. The scoria cones show a wide range of morphologies and morphometries that can be related to different syn - and post-eruptive processes. Cones with large craters and high crater width / basal width ratios show clear evidence of phreatomagmatic eruptions (within their pyroclastic successions), whereas horseshoe-type cones are related to cone breaching or coeval lava flow effusion, and more pristine (i.e., relatively younger) cones are generally steeper. • First morphometric analysis of scoria cones in northern Chile. • Negros de Aras volcanic field contains 66 volcanic centers (44 scoria cones and 22 vents). • A local extensive regime and inherited N-S structures determined the spatial distribution of the scoria cones. • The MORVOLC algorithm with a TanDEM-X 12 m spatial resolution was used for calculating morphometric parameters. [ABSTRACT FROM AUTHOR]

Effusion rate is the instantaneous lava flow output by a vent. It is one of the most important factors that govern the emplacement and dynamics of lava flows and can be determined by direct measurements or estimated through modeling. The Negros de Aras monogenetic volcanic field, located in the Central Volcanic Zone of the Andes, is the largest volcanic field in northern Chile. It is situated north of the active Socompa volcano and south of the Salar de Atacama basin, consisting of scoria cones and lava flows. Here, we estimate the effusion rates of three overlapping and representative solidified lava flows from this volcanic field applying an iterative procedure using the Q-LavHA GIS plugin, where the effusion rate is treated as an unknown parameter and the solution is reached by comparing the simulated results with the real extension of the flows. The pre-eruptive surface was reconstructed using the 12 m resolution TanDEM-X digital elevation model. Other required input parameters for the modeling (e.g., channel ratio, viscosity, temperature) were estimated through geomorphometric, petrographic, and geochemical analysis. The estimated effusion rates vary between 14 and 113 m3/s, comparable with rates measured elsewhere. The method was validated by applying it to two directly measured (Nyamuragira 2006; Mount Etna 2001) and one calculated effusion rate (Lentiscal 2450 BP, Canary Islands). The estimated effusion rates gave an average underestimation of 10%. Considering this percentage of adjustment, the effusion rates for the three studied lava flows from the Negros de Aras monogenetic volcanic field vary from 15 m3/s to 124 m3/s. Our results provide valuable information for mitigating volcanic risk in the event of future lava flow eruptions, which could affect nearby villages and mining operations. • Estimation of effusion rate of cooled lava flows in the Negros de Aras monogenetic volcanic field. • Estimation of effusion rate using the lava flow simulation software Q-LavHA GIS. • Lava flows morphotypes vary from 'a'ā type to blocky type. • The pre-eruptive surface was modeled using the TanDEM-X 12 m spatial resolution digital elevation model. [ABSTRACT FROM AUTHOR]

The Tilocálar volcanic complex comprises four monogenetic volcanoes located at the southeastern edge of the Salar de Atacama Basin, northern Chile. These monogenetic volcanic centers are the Tilocálar Norte lava, the El Maní dome, the Tilocálar Sur small–lava shield, and the Tilocálar Sur maar, respectively, and were formed between 460 ± 50 ka to < 1 Ma ago along the north–south-striking Tilomonte ridge that underlies the Tucúcaro Ignimbrite (3.2 ± 0.3 Ma). Their formation is the result of an intermediate magma rising to the surface during a local transtensional regime, which is observed at El Maní, under a dominantly compressional tectonic setting. The Tilocálar monogenetic centers provide a rare opportunity to examine the variability from individual and small–volume magma batches to the development of a monogenetic volcanic field. These volcanoes and the control on their eruption styles were studied by geological mapping and stratigraphic considerations, morphometric analysis, textural studies (density and vesicularity), petrographic observations, and geochemical analyzes. The Tilocálar Norte lavas have an intermediate composition (mostly andesite, 62.02 wt.% SiO 2) that reach a maximum distance of 3.9 km to the north and 1.2 km to the southwest from their vent, with a dense–rock equivalent (DRE) volume of 8.73×107 m3. The El Maní lava dome is small (covering 750 m2 area and consisting of 1.06×103 m3 DRE volume) that presents mingled mafic (63.89 wt.% SiO 2) and felsic (73.73 wt.% SiO 2) products of the original magma source, related to shallow crustal melts. The Tilocálar Sur small lava–shield is characterized by a pyroclastic fall deposit and lavas. The pyroclastic fall deposit is characterized by agglutinated andesite scoria–spatter fall units, covering 2.81 km2 and consisting of 7.75×105 m3 DRE volume. In contrast, the lavas are characterized by an andesitic composition (57.64 wt.% SiO 2), which is 1.8 km in length to the northwest and 1.4 km to the east of their source. These lavas cover an area of 3.78 km2 with 9.15×107 m3 DRE volume. Tilocálar Sur maar crater has an elliptical shape in map view (363 m diameter east–west and 288 m diameter north–south), surrounded by individual conglomerates, sandstones, granitoids, and tuff fragments that lie on the present–day surface around the crater rim. The Tilocálar volcanic complex is interpreted as a small monogenetic volcanic field that shows an eruption history defined by a spectrum of eruptive processes determined by internal and external parameters at any given time from the four independent volcanic centers. • Four monogenetic centers are characterized as the Tilocálar monogenetic volcanic field. • Magmatic effusive, magmatic explosive, and phreatomagmatic activity is evidenced. • The Monturaqui-Negrillar-Tilopozo aquifer is associated with the Tilocálar Sur maar. • The El Maní dome with flow–mingled textures indicates a local transtensive regime. • A local transtensive regime is proposed for the Tilocálar volcanoes emplacement. [ABSTRACT FROM AUTHOR]

Cerro Tujle is an isolated Quaternary maar located 21 km south-east of the Salar de Atacama basin. It is situated at 3,554 m a.s.l., on the top of the Cordón de Tujle ridge forming a north-south striking morphological element in the Central Volcanic Zone of the Andes, in northern Chile. The material erupted at Cerro Tujle lies over the Tucúcaro Ignimbrite (3.2 ± 0.3 Ma), covering the whole area. The origin of the magma source, as well as the evolution and control of the volcanic eruptive styles, were determined by fieldwork, stratigraphic, morphometric, textural (density and vesicularity), petrographic, and geochemical analyses. The Cerro Tujle maar features an elliptical crater (333 × 279 m wide in east-west and north-south directions, respectively) surrounded by lava flow and tephra deposits. The total Dense Rock Equivalent volume of the products was calculated in 1.53 × 105 m3, and mainly correspond to andesites (58.62–59.80 wt% of SiO 2). The lava flow can be categorized in at least two types: i) brown-red and green-to-gray andesites located on the north-northwestern flank of the crater, and ii) black andesites with felsic rock clasts distributed around the crater underlying the other lavas. In contrast, the pyroclastic deposit displays breccias of juvenile pyroclasts with xenoliths of rhyolitic composition. These felsic clasts suggest magma assimilation with a shallow magma reservoir during a relatively fast ascent of the magma. This is evidenced by disequilibrium textures in mineral levels, such as reaction rim, and skeletal and sieve textures of the phenocrysts. The field evidence and results of the different analyses suggest a change in the eruptive style from effusive to explosive. This transition is associated with a decrease of the magma flux and a withdrawal of magma below the groundwater table, which has produced a phreatomagmatic eruption by magma-water interaction. • The field relationships between lava flow emission and pyroclastic surge deposit. • Changing eruptive styles in intermediate volcanism. • The hydromagmatic explosive eruptions are not uncommon in the Altiplano-Puna region, northern Chile. [ABSTRACT FROM AUTHOR]

The central library of the Technical University of Manabí (UTM), provides the service of loans of electronic equipment (laptops and tablets), in which theft has occurred. This article describes the integration of RFID through a web application. For this, the requirements were raised, systems analysis and identification technologies were analyzed, based on the study of art the development methodology, programming languages, tools and technologies applied in the solution were described, the system architecture was designed With visual / audible alarm, the integrator system was developed and implemented and finally function tests were executed. As a result, it was evidenced that using barcode and RFID technology in the library service there is a better control of entry and exit of electronic equipment, preventing any attempt of theft, and the university and general community receives a quality service and speed. [ABSTRACT FROM AUTHOR]

In the transfer of students with visual disabilities at the Technical University of Manabí (UTM) accidents have been reported when going through some ramps and other obstacles, especially on rainy days. This article belongs to an investigation into the realization of an alert system for students with visual disabilities. The objective of the implementation of this system is to guide students with visual disabilities on different obstacles that exist in their transfer through the university. To carry out the implementation of this system, the alert systems and the technologies that are currently used as a result of a recording studio in the national and international scope were analyzed, the tools and technologies used in the developed solution are described. (Definition, technologies for the change of people, software, programming languages, etc.) that allowed an efficient implementation in a short time of the proposed system by means of RFID (Radio Frequency Identification) technology. The above is reflected in the positive orientation for the transfer of 32 students with visual disabilities through the university and by those who have contributed to improving their quality of life. [ABSTRACT FROM AUTHOR]

Volcano sector collapses are catastrophic events that can mobilize huge volumes of material and cause changes in the magmatic plumbing system, leading to variations in growth rate and/or composition. Dating pre-historic volcanic debris avalanche deposits is challenging. Geological materials directly recording avalanche formation and amenable to radiometric dating are rare, and, in the case of Holocene events, the applicable radiometric dating techniques are scarce. Socompa volcano suffered the largest collapse event in the Central Volcanic Zone of the Andes, producing one of Earth's most spectacular and best-preserved volcano avalanche deposits. We apply multiple dating techniques to unravel the timing of Socompa's collapse and gain insights into its pre- and post-collapse eruptive history. The age of the collapse event is constrained by a 14C age of 6,200–6,400 BP of a paleosol buried by the avalanche, and by a post-collapse lava flow dated at 5.91 ± 0.43 ka by zircon double-dating. Bayesian age sequence modeling integrating these ages determines that the collapse occurred at 6.18 - 0.64 + 0.28 ka. Four zircon eruption dates and one unspiked K–Ar age between 69.2 ± 6.0 and 22.1 ± 1.9 ka constrain the age of the youngest stage of activity before the collapse. The ages, together with paleosurface modeling and volume calculations, allow estimating growth rates for the young pre-collapse and post-collapse stages of ~ 0.2–0.3 km3/kyr and ~ 0.5–2 km3/kyr, respectively, indicating a significant increase in activity after the collapse event. The collapse may have triggered a new growth phase or accelerated an ongoing one and was likely associated with a Plinian eruption that produced widespread pumice fallout. The pre- and post-collapse lavas have similar compositions and zircon crystallization age distributions, suggesting that the same or a similar magma reservoir was tapped before and after the collapse. Thus, huge collapses such as Socompa's event can promote increased volcanic activity as a consequence of the unloading effect, but the overall plumbing system may not be affected enough to show significant variations in erupted compositions, at least transiently. Our results highlight the efficacy of the zircon double-dating method for dating very young felsic lavas and for constraining the age of debris avalanche deposits. This is particularly relevant in the Andean Central Volcanic Zone and other regions with arid climates, where organic material is rare and hence 14C dating is often unfeasible. Furthermore, the post-collapse zircon eruption age of 5.91 ± 0.43 ka is the youngest radiometric age yet obtained for a lava flow in the southern Central Volcanic Zone, highlighting the youth of volcanic activity at Socompa, and confirming its status as a Holocene active volcano. [ABSTRACT FROM AUTHOR]

The Central Volcanic Zone of the Andes (CVZA) has been the focus of volcanological research for decades, becoming a very important site to understand a number of volcanic processes. Despite most of the research in the CVZA being carried out by foreign scientists, the last two decades have seen a significant increase in contributions by regional researchers. This surge has been facilitated by the creation of new volcanic observatories, improvement of the monitoring networks, creation of postgraduate programs where new local volcanologists are trained, creation of specialized research nuclei or groups, and increasing investment in research. This article presents a review of the evolution of the contributions of the regional volcanological community to the knowledge of the CVZA in the last 20 years (2000–2019), both from research and monitoring institutions in Peru, Bolivia, Argentina, and Chile. Based on updates made by the regional groups, a new list of active/potentially active volcanoes of the CVZA is presented, as is a complete database for article published on the CVZA. We find that a significant motivator has been regional volcanic unrest that has triggered new investment. Perú is the country with the highest investment in monitoring and research and is the best instrumented, Argentina is the country with the highest number of local participation in published papers in the domain of volcanology and magmatic systems, and Chilean volcanoes are the focus of the highest number of articles published. The current situation and general projections for the next decade (2020–2030) are also presented for each country, where we believe that the over the next 10 years, will be increased the monitoring and research capabilities, improved the scientific knowledge with more participation of regional institutions, and strengthen the collaboration and integrated work between CVZA countries, especially in border volcanoes. [ABSTRACT FROM AUTHOR]

El País is a monogenetic lava flow field located 16 km southeast of Peine town in the Altiplano-Puna area, Antofagasta region, Chile. El País is a monogenetic lava flow field located 16 km southeast of Peine town in the Altiplano-Puna area, Antofagasta region, Chile. El País is composed by lava flows of small-to-moderate volumes, which are fed from individual point sources unassociated with a central volcano of large-volume (stratovolcano) typical of the Andean arc. This lava flow field was emplaced in an area dominated by thin-skinned deformation under a compressive tectonic regime, where multiple volcanic centers (monogenetic and polygenetic volcanoes) have been developed. The volumetric and chemical evolutions were determined by fieldwork, stratigraphic, morphometric, textural (density and vesicularity), petrographic, and geochemical analyses. El País can be divided into three principal mafic lava flows such as Northern-, Main-, and Western-lava flows, which display an E-W orientation. Besides, at least eight ephemeral vents were identified as small erosion remnants of lava emitting point-sources. The identified vents are principally aligned in an ENE-WSW direction, east of the Main lava flow. It is inferred that El País was emplaced near-simultaneously above two ignimbrite sheets: Tucúcaro Ignimbrite (3.2 Ma) and Patao Ignimbrite (3.1 Ma). Stratigraphically, the Main lava flow has a surface texture with strong similarities to an ʻaʻā lava flow, composed of three unique layers well distinguishable in the field such as i) Basal, ii) Top auto-breccia, composed of sub-angular scoriaceous and dense clasts in an oxidized matrix, and iii) A single core between both auto-breccias, composed of dense lavas, exhibiting multiple cooling jointing, such as vertical to platy jointing. The advanced stage of erosion since the formation of El País is evidenced by the poorly preserved lava flows (flat morphology), upper auto-breccia layer, and the presence of large sub-angular blocks of lava (vesicular and dense) along the axis of the lava flows. The eruptive products are geochemically basaltic andesite (Main lava flow and ephemeral vents) and andesite (specifically in the Northern lava flow), making the lava flow field one of the most mafic in the broader region. The lava presents a glomeroporphyric texture, showing at least three different glomerocrysts: i) Plagioclase + clinopyroxene having reabsorption boundaries, ii) Clinopyroxene with reabsorption boundaries, and iii) Plagioclase with sieve-texture. The groundmass is principally composed of glass, plagioclase microlites with a low orientation preference, and opaque minerals (magnetite). This study helps understand the development of dispersed-monogenetic-volcanism (e.g., Tilocálar complex and Cerro Tujle maar), and its relationship with neighboring polygenetic volcanism (e.g., Toloncha stratovolcano) in the Central Volcanic Zone of the Andes, northern Chile. • Different vent location during effusive eruption in lava flow field context. • Ascent rate of basic and intermediate volcanism related with deep source and low magma supply. • Erosion process in dessert climate. [ABSTRACT FROM AUTHOR]

UV cameras have been used for over a decade in order to remotely sense SO2 emission rates from active volcanoes, and to thereby enhance our understanding of processes related to active and passive degassing. Whilst SO2 column density retrievals can be more accurate/sophisticated using alternative techniques (e.g., Differential Optical Absorption Spectrometer (DOAS), Correlation Spectrometer (COSPEC)), due to their higher spectral resolutions, UV cameras provide the advantage of high time-resolution emission rates, a much greater spatial resolution, and the ability to simultaneously retrieve plume speeds. Nevertheless, the relatively high costs have limited their uptake to a limited number of research groups and volcanic observatories across the planet. One recent intervention in this regard has been the introduction of the PiCam UV camera, which has considerably lowered instrumental cost. Here we present the first data obtained with the PiCam system from seven persistently degassing volcanoes in northern Chile, demonstrating robust field operation in challenging conditions and over an extended period of time, hence adding credence to the potential of these units for more widespread dissemination to the international volcanic gas measurement community. Small and weak plumes, as well as strongly degassing plumes were measured at distances ranging 0.6–10.8 km from the sources, resulting in a wide range of SO2 emission rates, varying from 3.8 ± 1.8 to 361 ± 31.6 td−1. Our acquired data are discussed with reference to previously reported emission rates from other ground-based remotely sensed techniques at the same volcanoes, in particular considering: resolution of single plume emissions in multi-plume volcanoes, light dilution, plume geometry, seasonal effects, and the applied plume speed measurement methodology. The main internal/external factors that influence positive/negative PiCam measurements include camera shake, light dilution, and the performance of the OpenCV and control points post processing methods. A simple reprocessing method is presented in order to correct the camera shake. Finally, volcanoes were separated into two distinct groups: low and moderate SO2 emission rates systems. These groups correlate positively with their volcanological characteristics, especially with the fluid compositions from fumaroles. [ABSTRACT FROM AUTHOR]

A detailed study on the mineralogy and chemistry of fumarolic deposits with a focus on metals and metalloids is presented. Two active volcanoes in northern Chile, Guallatiri and Lastarria, are characterised by vigorous and persistent fumarolic activity and the formation of zoned fumarolic deposits. Twelve minerals were identified in the studied deposits by X-ray diffraction: anhydrite, barite, gypsum, rhomboclase, orpiment, pyrite, galena, cristobalite, quartz, magnetite, sassolite, and native sulphur. Chemical analyses revealed the presence of 30 chemical elements, including metals and metalloids such as As, Hg, Pb, Sb, Te, and Tl. Backscattered-electron imaging revealed four types of rock textures in the fumarolic deposits: i) massive and poorly vesiculated, ii) highly vesiculated, iii) clastic-like, and iv) flow-like. Micro-chemical analyses showed the presence of cinnabar nataliyamalikite and unidentified mineral assemblages of As S, Te S, Pb S, Hg S, Tl I, and Tl-I-Pb compositions. Based on colour, outlet gas temperature, mineralogy, and chemistry, four distinct zones of fumarolic deposits are identified. (1) Grey zone: sulphide and silicate dominant with minor native elements, high concentrations of Pb and As, and a clastic-like texture (gas outlet temperature > 265 °C). (2) Red zone: sulphide and silicate dominant with minor oxides and native elements, small As, Pb, Tl, I, and Te minerals, and predominance of a flow-like texture (200–280 °C). (3) Yellow-orange zone: dominated by native sulphur and minor borates and sulphur with small As-, Sb-, Hg-, and I-containing minerals, massive and vesiculated texture (80–200 °C). (4) Yellow-white zone: formed by native sulphur, minor borates and As-rich zones, usually displaying a vesiculated texture (<100 °C). • Mineralogy and chemistry of fumarolic deposits of Guallatiri and Lastarria volcanoes are investigated. • Native sulphur is the most common mineral in fumarolic deposits. • Rare As S, Te S, Pb S, Hg S, Tl I, and Tl-I-Pb mineral assemblages were found. • A detailed description of northern Chilean fumarolic deposits is provided. [ABSTRACT FROM AUTHOR]