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27th IUGG General Assembly 2019 in Montreal, 8-18 July 2019, In 2008 we presented a new general worldwide Collapse Caldera DataBase (CCDB), in order to provide a useful and accessible tool for studying and understanding caldera collapse processes. The main aim of the CCDB was, and still is, to update the current field based knowledge on calderas, merging together the existing databases and complementing them with new examples found in the bibliography, and leaving it open for the incorporation of new data from future studies. After the most recent update in January 2019, the database includes over 630 documented calderas worldwide, trying to be representative enough to promote further studies and analyses. We have performed a broad compilation of published field studies of collapse calderas including more than 520 references. Since 2015, the CCDB is available on-line, http://www.gvbcsic. es/CCDB.htm, where the user can query the database according to different collapse caldera features such as age, magma composition, etc. The information recorded in the CCDB can be grouped in seven main information classes: caldera features, properties of the caldera-forming deposits, magmatic system, geodynamic setting, pre-caldera volcanism, caldera-forming eruption sequence and post-caldera activity. This research was partially funded by the research project SIMPROP(CGL2017-84901-C2-1-P) and the fellowship RYC-2012-11024., This research was partially funded by the research project SIMPROP(CGL2017-84901-C2-1-P) and the fellowship RYC-2012-11024

6 páginas, 4 figuras, 4 tablas, 1 lámina., [ES] El estudio de rocas andesíticas de la Isla King George (Archipiélago de las Shetland del Sur, Antártida) pone de manifiesto la existencia de procesos de alteración hidrotermal con la formación de minerales zeolíticos secundarios pertenecientes a asociaciones de baja temperatura. Se han identificado dos paragénesis (Esmectitas-Bytownita-Mordenita, Esmectitas-AlbitaLaumontita) que reflejan distintas condiciones durante la alteración hidrotermal de dichas rocas andesíticas., [EN] The study of some andesites from King George Island (South Shetland Islands, Anctartica) has pointed out the existence of a hydrothermal alteration process going rise to a zeolitic secondary minerals of low-temperature assemblages. Two paragenesis have been identified (Smectite-Bytownite-Mordenite, Smectite-Albite-Laumontite) which reflecting different conditions durign the hydrothermal alteration of these andesitic rocks.

14 páginas, 11 figuras, 1 tabla., [ES] El Coranzuli es uno de los grandes complejos volcánicos que representan el remate final de las Cadenas Volcánicas Transversales de la Puna Argentina, en los Andes Centrales. Se trata de un complejo volcánico del Mioceno superior situado a los 66º 15' W 23º S en el NW de Argentina en la provincia de Jujuy, en la intersección entre dos fallas regionales de dirección NE-SW y NW-SE, respectivamente. La actividad eruptiva se caracterizó por la existencia de, al menos, cuatro erupciones ignimbríticas que produjeron cuatro diferentes mantos ignimbríticos. Se trata de ignimbritas bien soldadas, muy ricas en cristales, pobre en fragmentos líticos y que presentan un contenido en fragmentos pumíticos de moderado a alto. El volumen total que representan estas ignimbritas supera los 650 km3. Los datos preliminares indican que el magma juvenil deriva de una cámara magmática homogénea no zonada. Las características de emplazamiento de estas ignimbritas, así como la falta de depósitos plinianos de caída en la base o intercalados entre las ignimbritas sugieren que las erupeiones se desarrollaron rápidamente en unas proporciones masivas., [EN] The Coranzulí is a large Upper Miocene volcanic complex located on a NE-SW and NW-SE regional faults intersection, at 66 15' W 23" S, in the Northwest of Argentina in Jujuy province. It corresponds to one of four large volcanic complexes which represent the end of Transversal Volcanic Chaines in La Puna Argentina in the Central Andes. The volcanic aetivity was characterized by at least four separate ignimbrite eruptions which produced four different ignimbrite sheets. These are well welded, very crystal-rich, lithic poor ignimbrites and have a moderate to high pumice content. The total volume of the Coranzuli ignimbrites excededs 650 Km3. Preliminary data indicate that the eruption occurred from a homogeneous magmatic chamber without zoning. The emplacement characteristics of the ignimbrites and the lack of basal or interbedded plinian fall deposits suggest that the eruptions developed quickly to massive proportions.

Simulating lava flows on a gentle slope is complex since they can propagate in a wide range of directions. It is an even greater challenge to define lava flow trajectories when an eruption lasts over several years and flows cool down, changing the surrounding topography. In this study, we test Q-LavHA, an open source plug-in that simulates lava flow inundation calculating its probability, and using Paricutin’s eruption (1943–1952) in central Mexico as a case study. We have appropriately calibrated the Q-LavHA plug-in for the Paricutin case study, which provides insights on how to better model lava flows in gentle terrain. From this work, we observe that each phase is characterized by a unique set of parameters requiring a careful calibration and that low-relief topographies require special consideration. Our findings could be useful for real-time hazard evaluation in future volcanic scenarios in the Michoacán–Guanajuato volcanic field and elsewhere, where new monogenetic eruptions similar to Paricutin can be expected., This research was supported by the Government of Spain through “Juan de la Cierva” postdoctoral fellowship awarded to L. Becerril; NSF EAR 1019798 (2014–2016) and a UNAM-DGAPA postdoctoral fellowship (2018–2019) granted to P. Larrea; National Science Foundation (NSF) EAR grant #1019798 awarded to E. Widom. Consejo Nacional de Ciencia y Tecnología (CONACyT-167231) and Dirección General de Asuntos del Personal Académico (UNAM-DGAPA-IN-104221) granted to C. Siebe; and VeTOOLS and EVE projects funded by the European Commission (EC ECHO SI2.695524 and 826292EC ECHO SI2.695524) granted to J. Martí.

Camp dels Ninots is a mixed hard-soft maar-diatreme located in the Catalan Volcanic Zone (NE of Iberia), in which intra-maar lake sediments have preserved one of the most remarkable Pliocene fossil records in Europe. Geophysical surveys combined with the geological map and 11 boreholes, including two new continuous intra-crater drill cores, have enabled the construction of a 3D geological model of this maar-diatreme and its basement. The formation of this maar-diatreme started with a vent-opening phreatomagmatic explosion at the intersection between a regional fault and the Paleozoic groundwater level at a depth of 210 m. We infer and calculate the geometry, dip direction and dip angle of this regional fault. During the eruption, mixed Strombolian and phreatomagmatic episodes occurred, forming the tuff ring and filling the diatreme with minimum estimated volumes of 0.012 and 0.004 km3, respectively. The diatreme infill is composed of three main lithofacies that include tuff-breccias, welded scoriae, and mafic intrusions into the phreatomagmatic breccias. Thus, the stratigraphy of the diatreme succession suggests a progression of explosive events from deeper to shallower zones with short lateral migration of explosion vents, which control its final morphology, without evidence for significant deep enlargement of the diatreme during the later phases. This generated a wide funnel-shaped with low diatreme wall angles that differs from kimberlite pipes with great depths and sharp slope geometries. Hence, such 3D geological model helps to understand the complex architecture of maar-diatreme structures, highlighting the lack of geological modeling of this type of monogenetic system., We would like to thank the landowners, especially Mr. Jaume (Met), for their permission and help to work in the area, and the Town Council of Caldes de Malavella. We also would like to the Departament de Cultura of the Generalitat de Catalunya for the economic funding of the drill coring campaign under the project CLT009/18/00052. This study was partially funded by the project of the Spanish Government and the SGR2017-859 and SGR-2017-1666 projects of the Generalitat de Catalunya. X. Bolós was funded by a UNAM-DGAPA postdoctoral fellowship (2016–2018). O. Oms is part of SGR-2017-1666 Research Group of the Generalitat de Catalunya. B. Gómez de Soler and G. Campeny are funded by the CERCA Programme/Generalitat de Catalunya. The Institut Català de Paleoecologia Humana i Evolució Social (IPHES-CERCA) has received financial support from the Spanish Ministry of Science and Innovation through the ‘María de Maeztu’ program for Units of Excellence (CEX2019-000945-M).

Extreme geohazards (volcanic eruptions, earthquakes, landslides, and tsunamis) have the potential to inflict cascading effects whose associated risks are difficult to predict and prepare for. Thus, these events are generally not taken into account in hazard assessment. Anticipating the occurrence of such extreme events is thus key if our life-styles are to remain safe and sustainable. Volcanic islands are often the source of complex successions of disastrous events, as is evident from any examination, for instance, of the geological record of regions such as Hawaii, the Canary Islands, Reunion and Indonesia. The island of Tenerife in the Canary Archipelago is an excellent example of where cascading extreme hazards have occurred several times in the past and could occur again in the future. A cascading sequence involving a caldera-forming eruption, high-magnitude seismicity, mega-landslides and tsunamis occurred at least twice during the construction of this island. In order to understand the possible consequences of such processes if they were to reoccur, we simulated the extent and potential impact of a multiple, extreme geohazard episode similar to the last recorded one that took place on the island of Tenerife around 180 ka. The implications of such a disastrous succession of events are analyzed at local, regional and global scales, and the results obtained are discussed within the framework of disaster risk-reduction policies., This research was partially funded by the EG grant EVE (DG ECHO H2020 Ref: 826292). Marta López-Saavedra received a CSIC JAE Intro grant (JAEINT 19 01465), and an FPU PhDgrant (FPU19/02413).

The manuscript has been benefited from valuable suggestions from Mattia Pistone and Jiri Zak. This work is supported by IBERCRUST project (PGC2018-096534-B-I00). C. R. is grateful for her AUIP grants (Asociacion Universitaria Iberoamericana de Postgrado) for both stays at the Universidad Nacional de La Plata (Argentina), during 2015 and 2018, and for her postdoctoral contract from the University of Huelva (under the Estrategia Politica Cientifica de la UHU 2016/2017). This is the IBERSIMS publication n.85. JM is funded by the MINECO grant CGL2017-84901-C2-P1., The Paleocene-Eocene Cerro Munro pluton, to the east of the North Patagonian Batholith (NPB), is a tonalitic intrusion emplaced as a shallow, small, sub-circular tonalite-granodiorite body hosting abundant co-magmatic mafic microgranular enclaves (MME). Besides, the intrusive body is crosscut by radial porphyritic dikes and has been related to andesitic, dacitic and rhyolitic dikes, lava flows and ignimbrites cropping out at neighboring areas. Magmatic contacts between MME and host tonalites, together with their common geochemical features, suggest derivation from a common parental magma, although short-range mineralogical and geochemical differences point to an early crystallization of MME (chilled margins) at the sidewalls of ascent conduits or at shallow reservoirs. The established thermal gradient and the advance of the solidification front were responsible for the presence of the mafic microgranular and tonalitic subsystems and, in a continuous process, promoted the water saturation and the second boiling that finally account for the segregation of a water rich highly differentiated residual liquid. Hbl-Pl cumulate textures observed in the tonalites and mafic enclaves, as well as incompatible element-enriched rhyolitic melts record the results of this in-situ differentiation process. U–Pb zircon ages obtained from tonalites (57.1 ± 1.4 Ma), dacitic (55.4 ± 0.6 Ma) and rhyolitic (54.1 ± 0.7 Ma) dikes constrain an age of around 54 Ma for the final consolidation of the tonalitic magma and the crystallization of the expelled highly differentiated melts. This age coincides with the deposition of dacitic volcanic and volcanoclastic deposits to the north of the Cerro Munro pluton, which suggests that the fractionation process led to the extrusion of segregated melts, favored by extension, uplift and exhumation of an active rift tectonic setting., IBERCRUST project PGC2018-096534-B-I00, AUIP grants (Asociacion Universitaria Iberoamericana de Postgrado), University of Huelva, MINECO CGL2017-84901-C2-P1

Understanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences. Volcanoes erupt with variable reaction times as a consequence of the impact of seismic waves (i.e. dynamic stress) and changes in the stress field (i.e. static stress).In2012, three large(Mw≥7.3)subductionearthquakes struck Central Americawithin a period of 10 weeks;subsequently, some volcanoesin the regionerupted a few days after, whileotherstook months or even years to erupt. Here, we show thatthese threeearthquakes contributed to the increase in the number of volcanic eruptionsduring the 7 years that followed these seismic events. We found that onlythosevolcanoes that were already in a critical state ofunrest eventually erupted, which indicates that the earthquakes only prompted the eruptions. Therefore, we recommend the permanent monitoring of active volcanoes toreveal which are more susceptible to culminate into eruption in the aftermath of the next large-magnitude earthquake hits a region., Funding was provided by Japan International Cooperation Agency (JICA) and Istitute Nazionale di Geofisica e Vulcanologia (INGV).

The dimensions, the geographical position and the complex geological history of the Iberian Peninsula makes it a unique and singular target to study its crustal and upper mantle structure and geodynamical evolution using geophysical methods. The lithospheric structure beneath Iberia has been investigated since the 1970’s using deep multichannel seismic reflection and refraction/wide-angle reflection profiling. Gravimetric and magnetic data were acquired following the deployment of permanent and temporary stations, mostly during the 1990’s. Beginning in the late 1990’s, the progressive use of Global Navigation Satellite Systems (GNSS) instruments contributed to monitor the present-day motions. During the last decades, numerous geological and geophysical surveys have investigated the Iberian lithosphere and upper mantle in the onshore and offshore regions, the most recent ones related to the TopoIberia project. The approach developed in this contribution is twofold. Firstly, we summarize the available geophysical information over Iberia, from focusing on the upper crust to the lithosphere-asthenosphere boundary and the transition zone marking the bottom of the upper mantle. Results of GNSS data, potential fields, controlled source seismic profiles, magnetotelluric data, body and surface wave tomography, receiver functions and 2D and 3D lithospheric modeling are reviewed and compared. Secondly, we focus on the areas of greater geodynamic interest and the regions where inconsistencies within the geophysical results, or contradictions in their tectonic interpretation exist, identifying the major questions that are still under debate. Besides shedding light to the state of knowledge and pointing out present-day research challenges, this review provides a tool for the integration of the diverse geophysical datasets with the surface geology and geodynamical processes that are interpreted to have built the complex geology of the Iberian Peninsula., The authors acknowledge funding from the Generalitat de Catalunya, grant/awards number AGAUR 2017SGR1022, and AGAUR 2017SGR847, the Spanish Ministry of Science, Innovation, and Universities grant numbers RTI2018-095594-B-I00, PGC2018-095154-B-100 and PGC2018-094227-B-I00 and the Spanish Ministry of Economy and Competitiveness grant numbers CGL2017-84901-C2 and PIE-CSIC-201830E039. IP is funded by the Spanish Ministry of Science, Innovation, and Universities and University of Salamanca grant BEAGAL18/00090. AV acknowledges funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S).

San Miguel volcano (or Chaparrastique), one of El Salvador's most active volcanoes, has erupted 28 times in the past 431 years (historical period). The majority of historical eruptions have been Strombolian (VEI 1–2) that have occurred from the central vent and have generated ashfall and ballistics, but some of them (8) have been effusive flank eruptions, mainly producing lava flows of basaltic and basaltic-andesite composition. Secondary lahars generated by remobilization of the young tephra are also common at San Miguel volcano. Using the information for these historical as well as prehistoric eruptions and applying probabilistic tools designed for volcanic-hazards assessment, we simulated: (1) the five most likely scenarios (ashfall scenarios, local-moderate extent, and VEI 1–2); (2) other probable scenarios related to lava flows, based on the historical record of the volcano; (3) other possible scenarios related to pyroclastic density currents (PDCs) with similar characteristics to those that occurred during its eruptive history; and (4) the most hazardous scenarios (ashfall, lava flow, PDC) that have been identified from its prehistoric geological record. Finally, we construct a qualitative integrated volcanic hazard map through the combination of the simulated scenarios. This study was developed with the aim of improving the existing volcanic-emergency plan. It should serve to improve the collaboration and coordination between scientists, the national observatory (OA-MARN), and the civil protection agency of San Miguel municipality, and will help to strength this cooperation to respond effectively to future volcanic crises., This research was partially funded by Grant I-COOPA20161 (CSIC).

We present a detailed stratigraphy of the Coranzulí caldera-forming deposits. This caldera, located in the Altiplano-Puna Volcanic Complex (Central Andes), generated four ignimbrite deposits with similar field characteristics and facies that differ from each other in, above all, the nature of the lithic fragments they contain. Three different lithofacies (fine-grained cross-stratified facies, massive lithic breccia facies and massive ignimbrite facies) are found in all the ignimbrite deposits, which occasionally also contain a lenticular lithic-rich facies and/or a pumice-rich facies. These field characteristics and, in particular, local deposit thicknesses were used to develop a theoretical model of the dynamics and emplacement mode of the Coranzulí pyroclastic flows. Our results show that these ignimbrites were emplaced by dense pyroclastic density currents subjected to high accumulation rates and velocities, thereby indicating rapid en masse emplacement that was also influenced by local paleotopography as deduced from facies analysis., This work was supported by Agencia Nacional de Promoción Científica y Técnica (PICT-2012-419; PICT-2017-2798; PICT-2017-1928) and the Consejo Nacional de Investigaciones Científicas y Técnicas (PUE 2016-2021), Argentina. SG is grateful to Elena López, Albano Floridia and Emanuel Ramos for their assistance in the field and Valmir da Silva Souza for the helpful discussions. JM is supported by the Spanish Grant CGL2017-84901-C2-1.

Anticipating volcanic eruptions at central volcanoes require knowing how magma chambers prepare for new eruptions. Pre-eruptive processes that occur in such magma chambers are recorded in the products of these eruptions, so their characterisation in terms of magma composition and physics offers the clues to understand past eruptions and predict future ones. Here, we study the very well preserved pyroclastic succession of El Palomar Member (712 ± 41 ka), in Las Cañadas caldera, Teide, Canary Islands. This deposit resulted from a single explosive eruption of a phonolitic magma that started with a sustained eruption column (sub-plinian or plinian) that formed a massive, 40 m thick non-welded fallout deposit, progressively changing into a lower intensity fire fountain that deposited a 25 m thick fallout succession of non-welded to strongly welded pumices. Stratigraphic and petrological data suggest that this eruption was related to a thermally-compositionally zoned and relatively shallow magma chamber in which the arrival of a hotter and more mafic magma rapidly triggered the eruption. The studied deposit shows how this zoned structure was maintained during the whole process, which allows one to reconstruct what happened during the eruption. Comparison of this eruption with the current situation at Teide volcano alerts on the potential rapid preparation for new eruptions in the case that sufficient phonolitic magma was available in the shallow plumbing system of this active volcano if new inputs of deeper magma take place.

The correct identification and interpretation of unrest indicators is useful for forecasting volcanic eruptions, delivering early warnings, and understanding the changes occurring in a volcanic system prior to an eruption. Such indicators play an important role in upgrading previous long-term volcanic hazard assessments and help explain the complexities of the preceding period of eruptive activity. In this work, we present a retrospective analysis of the 2011 unrest episode on the island of El Hierro, Canary Islands, that preceded a submarine eruption. We use seismic and surface deformation monitoring data to compute the susceptibility analysis (QVAST tool) and to study the evolution over time of the unrest (ST-HASSET tool). Additionally, we show the advantages to be gained by using continuous monitoring data and hazard assessment e-tools to upgrade spatiotemporal analyses and thus visualize more simply the development of the volcanic activity., This research was funded by the European Commission (EC ECHO Grant SI2.695524: VeTOOLS). Joan Martí is grateful for the MECD (PRX16/00056) grant.

Graben calderas are volcano-tectonic structures that use the faults of a graben as main vents from which magma is massively erupted from a shallow magma chamber during collapse of intra-graben blocks. These eruptions are generally silicic and explosive and form large volume ignimbrite sheets without a previous Plinian major depressurization event. Graben calderas can be associated to tectonic settings ranging from pure extension to strike slip ranstension, including complete grabens, half-grabens or pull-apart grabens. The Sierra Madre Occidental (SMO) in western Mexico includes several of these graben type calderas with the corresponding large volume ignimbrite sheets that result from fissure type eruptions along the graben’s border and interior faults. The Bolaños graben constitutes one of the best examples of these tectonically controlled collapse calderas and is the second largest caldera of the world after Toba caldera. It is a 90 x 25 km rectangular caldera and the vent of the 25.37 ± 0.36 Ma silicic Alacrán ignimbrite, with a minimum Dense Rock Equivalent volume of 2,650 km3 (3,800 km3 rock volume). Post-collapse silicic domes were emplaced just after the Alacrán ignimbrite from 25.02 ± 0.33 Ma to 23.94 ± 0.33 Ma, with a total minimum lava volume of 171 km3. Both ignimbrite and domes account for at least 2,800 km3 rhyolitic magma output from Bolaños graben caldera, without considering the distal deposits, and in particular the co-ignimbrite ash-cloud deposit. We describe the characteristics of the Bolaños graben caldera focusing on its major products, the Alacrán ignimbrite and the post-collapse dome volcanism, providing the geological frame of the Bolaños graben area documented with 40Ar-39Ar ages. We finally propose a conceptual model to explain the dynamics of the Bolaños graben that can be applied to other similar volcano-tectonic depressions of the Sierra Madre Occidental and elsewhere in the world with similar geological settings., We thank to the mining companies of the Bolaños district, Mina El Pilón, and to Compañía Minera México for logistical support through Ing. Javier de la Vega. We also thank the help of Mariana Coutiño, Isabel Hernández and Carmen Jaimes-Viera for applying GIS tools for map digitizing and volume estimation of the caldera units. The final version was greatly improved by comments and recommendations of referees and JVGR editor. This study was financed with grants to the first author from CONACYT P46005F and UNAM PAPIIT IN-124606, IN-106109, Spain’s sabbatical grant MICYT, and from several grants from the CIC-UNAM-CSIC and Barcelona Interchange Program. JM has been supported by the MINECO CGL2017-84901-C2-1 Grant. IGP thanks CONACYT for a Master thesis scholarship No. 195620.

The Angolan alkaline&ndash, carbonatite complex of Monte Verde has a semi-circular shape and is comprised of a central intrusion of foidolite rocks surrounded by concentrically arranged minor bodies of other alkaline rocks and carbonatite magmatic breccias. This rock association is hosted by fenitized Eburnean granites. Concentric swarms of alkaline dykes of late formation, mostly of nepheline trachyte composition, crosscut the previous units. Most high-field strength elements (HFSE) and rare earth elements (REE) are concentrated in pyrochlore crystals in the carbonatite and alkaline breccias. Magmatic fluornatropyrochlore is replaced and overgrown by five secondary generations of pyrochlore formed during subsolidus stages and have higher Th, REE, Si, U, Sr, Ba, Zr, and Ti contents. The second, third, and fourth pyrochlore generations are associated with late fluids also producing quartz and REE rich minerals, whereas fifth and sixth pyrochlore generations are linked to the fenitization process. On the other hand, minerals of the rinkite, rosenbuschite, w&ouml, hlerite, eudialyte groups, as well as loparite-(Ce), occur in accessory amounts in nepheline trachyte, recording low to moderate agpaicity. In addition, minor REE-bearing carbonates, silicates, and phosphates crystallize as late minor secondary minerals into carbonatite breccia and alkaline dykes. In conclusion, the scarcity of HFSE and REE minerals at the Monte Verde carbonatite-alkaline-agpaitic complex suggests low metallogenetic interest and economic potential for the outcrops analysed in this study. However, the potential for buried resources should not be neglected.

We present a new 1:80,000-scale geologic map of the Acoculco caldera (Ac) located between the states of Puebla and Hidalgo in eastern México. The map, encompassing an area of 856 km2, is grounded on an ArcMap data set and is supported by nine new 40Ar/39Ar dates. The caldera lies upon Cretaceous limestones and Miocene to Pliocene volcanic rocks (13–3 Ma). The caldera consists of 31 lithostatrigraphic units formed between 2.7 and 0.06 Ma that include a wide variety of volcanic landforms (cinder cones, lava domes). The caldera has a semi-circular shape (18–16 km) bounded by the Atotonilco scarp to the north, the NW–SE Manzanito fault to the west, and scattered vents to the east and southern parts. The distribution of the Acoculco ignimbrite, the lithic breccia, and lacustrine sediments define the caldera ring fault. Late Pleistocene activity and pervasive hydrothermal alteration suggest a high geothermal potential in the area. © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps, This study was funded by Grant 207032 of the Centro Mexicano de Inovación en Energía Geotérmica (CeMIE Geo) project P15 to J.L. Macías. JM is grateful for the MECD (PRX16/00056) grant.

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 20 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969, and 1970) and the volcanic unrest episodes that happened in 1992, 1999, and 2014–2015 demonstrate that the occurrence of future volcanic activity is a valid and pressing concern for scientists, technical and logistic personnel, and tourists, that are visiting or working on or near the island. We present a unifying evolutionary model of the magmatic system beneath Deception Island by integrating new petrologic and geochemical results with an exhaustive database of previous studies in the region. Our results reveal the existence of a complex plumbing system composed of several shallow magma chambers (≤10 km depth) fed by magmas raised directly from the mantle, or from a magma accumulation zone located at the crust-mantle boundary (15–20 km depth). Understanding the current state of the island’s magmatic system, and its potential evolution in the future, is fundamental to increase the effectiveness of interpreting monitoring data during volcanic unrest periods and hence, for future eruption forecasting. © 2019, The Author(s)., This research was supported by the MICINN grants RECALDEC (CTM2009–05919-E/ANT) and PEVOLDEC (CTM2011–13578-E/ANT), and the POSVOLDEC(CTM2016–79617-P)(AEI/FEDER, UE) and VOLCLIMA(CGL2015–72629-EXP)(AEI) projects. A.G. is grateful for her Ramón y Cajal contract (RYC-2012–11024). Analyses of stable isotopes were funded by the grant Programa Propio I (Usal-2014) through A.M.A-V.

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San Miguel, one of the most active volcanoes in El Salvador, is surrounded by several villages and cantons, which could be seriously affected in case of a new eruption. This study presents an exposure analysis of the San Miguel volcano area by considering population distribution, land use, private houses, official buildings (hospitals, schools, etc.), and communication infrastructure. We use spatial analysis Geographic Information System tools to estimate exposure for different volcanic hazards (air fallout, lava flows, pyroclastic density currents, lahars). Moreover, in the particular case of private houses and official buildings, we estimate a Vulnerability Index for the hazardous areas, applying the Physical Vulnerability Methodology based on the characterization of the type of construction materials of walls and roofs. We construct different exposure maps for: 1) population, 2) land use, 3) road networks, 4) schools, and 5) health centers. This approach identifies the elements at risk according to each potential hazard, thus providing the authorities with a comprehensive tool to better understand the problem and to define emergency plans to minimize risk. © 2019 Elsevier B.V., This research was partially funded by Grant I-COOPA20161 ( CSIC ).

The Coranzulí caldera (23°00′ S – 66°15′ W) is one of the least known caldera complexes in the eastern part of the Argentinian Altiplano-Puna plateau (Central Andes). It lies at the intersection of N-S, NW-SE and NE-SW fault systems and was formed about 6.6 Ma ago; during the eruption, four main crystal-rich dacitic ignimbrites were emplaced in different directions around the caldera. Caldera collapse was not homogeneous, rather it occurred along different sectors of the ring fault as subsidence progressed. The location of co-ignimbrite lag breccias and the composition of the dominant lithic fragments within the different ignimbrite flow units reveal how the caldera collapse developed. According to the succession of deposits, in particular the lack of an initial fallout and the presence of co-ignimbrite lag breccias associated with the different ignimbrite units, we interpret this caldera-forming eruption as a pulsating boiling-over event in which the caldera collapse developed immediately after the onset of the eruption, favored by a transtensive tectonic system. Within the central part of the caldera, there is Cerro Coranzulí, a resurgent dome that exposes a thick intracaldera ignimbrite succession covered by ~ 100-m-thick dacite lava flows that erupted at the end of caldera formation. © 2019 Elsevier B.V., SG would like to thank the Progama de Financiamiento Parcial para Investigadores run by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) that facilitated a research period of two years at the Instituto de Ciencias de la Tierra Jaume Almera (CSIC). SG is also grateful to Agencia Nacional de Promoción Científica y Técnica (PICT 419-2012) and the Consejo Nacional de Investigaciones Científicas y Técnicas (PUE 2016-2021) Argentina, and also to Elena López, Albano Floridia, and Emanuel Ramos for their assistance in the field and Valmir da Silva Souza for helpful discussions. RS thanks the Servicio Geológico Minero Argentino (SEGEMAR). JM was supported by grant CGL2017-84901-C2-1-P.

The Acoculco caldera complex (ACC) is located in the eastern part of the Trans-Mexican Volcanic Belt in the northern part of the State of Puebla. The complex sits at the intersection of two regional fault systems with NE-SW and NW-SE orientations. The ACC was built atop Cretaceous limestones, the Zacatán basaltic plateau of unknown age, early Miocene domes (~12.7–10.98 Ma), and Pliocene lava domes (~3.9–3 Ma). Detailed field mapping and stratigraphy studies complemented by 40Ar/39Ar and 14C dating allowed the division of the ACC volcanic succession into 30 volcanic units. Based on the new results and previous studies, the ACC eruptive chronology was grouped in four eruptive phases: syn-caldera, early post-caldera, late post-caldera, and extra-caldera. Inception of the ACC volcanism began around 2.7 Ma with the dispersion of an andesitic ignimbrite followed by the collapse of the magma chamber roof as attested by the presence of a lithic breccia in isolated parts of the caldera rim. The collapse produced a 18 × 16 km caldera depression which was partly filled by the ignimbrite (total volume of ~127 km3) followed by the establishment of an intracaldera lake of unknown total extension. Early post-caldera collapse activity (2.6–2.1 Ma) was restricted within the caldera producing 27 km3 of lava flows and domes dominantly of basaltic trachyandesite to basaltic composition. Late post-caldera collapse activity (2.0-1 km hosted in the Cretaceous limestones. These bodies might represent a series of horizontal mafic intrusions located at different depths that provide the energy that maintains the Acoculco geothermal system active., This study was partially funded by the Centro Mexicano de Innovación en Energía Geotérmica (CeMIE-Geo) project P15 and GEMex 4.4. to J.L. Macías. J. Marti is grateful for the MECD, Spain (PRX16/00056) grant.

Recent studies on intraplate volcanic islands reveal that magma ascends sub-vertically through these volcanic edifices, following well-defined zones in the lithospheric mantle and oceanic crust, and occasionally suffering lateral propagation along rift zones when it reaches very shallow depths. Visualizing the internal structure of the shallowest part of such magma plumbing systems is crucial to understanding magma transport and the location of basaltic volcanism in these volcanic environments. Tenerife (Canary Islands) is a very good example of an intraplate volcanic island, in which the distribution of basaltic volcanism includes well-defined rift systems, and wider monogenetic fields where cinder cones form clusters along different tectonic alignments. In order to characterize the structure of the uppermost part of the basaltic plumbing system of Tenerife, we conducted a detailed gravimetric study of the north-western, central, and southern sectors of the island. We developed a 3D density contrast model of the subsoil based on the application of a genetic algorithm for the inversion of gravity data. The results of our inverse modelling suggest that the observed gravimetric anomalies below the northwestern rift zone are shallow and aligned parallel to this structure. This is consistent with a shallow character for the rift system and a lateral migration of magma along it that comes from a deeper zone located towards the east of this rift zone. Conversely, the anomalies located in the south are also shallow but are distributed along more than one alignment and are connected to much deeper sub-vertical similar density anomalies. These results support the existence of several main channels at the north and south of the island that allow the ascent of deep basaltic magma to shallower zones of Tenerife. There, magma may be either caught by the rifts systems, being distributed laterally and occasionally erupting, or may continue its ascent to the surface using a secondary system of shallow fractures that dominates the southern part of Tenerife. The results of our inverse model also offer new insights on others aspects of the internal structure of Tenerife, such as the distribution of the basaltic shield or that of Las Cañadas caldera. © 2019 Elsevier B.V., Joan Martí was funded by the MECD ( PRX16/00056 ) grant. This work was partially supported by the Instituto Geográfico Nacional of the Spanish Ministerio de Fomento and through projects CGL2014-53044-R and CGL2015-63799-P of the Spanish Ministry of Economy and Competitiveness .

The Las Cañadas caldera is one of the best exposed volcanic calderas in the world and one of the few known evolved alkaline volcanoes. It truncates the pre-Teide-Pico Viejo central volcanic edifice, the Las Cañadas edifice, which started to take shape at the end of the formation of a large basaltic shield that forms the main part of island of Tenerife. Historically, the origin of the Las Cañadas caldera has been controversial, as it has been interpreted as the result of either multiple vertical collapses or due to a giant sector collapse. The available stratigraphical, structural, volcanological, geochronological, and geophysical data, as well as its comparison to other well-known collapse calderas should not offer any doubt as to its direct relationship with a long history of phonolitic explosive volcanism. However, the existence of large landslide events on Tenerife, which have significantly modified the flanks of the Las Cañadas volcano, have also been used as a potential explanation for the origin of the Las Cañadas depression. This contribution reviews the available information on the Las Cañadas caldera, the causes of this controversy, and rationalises the most plausible explanation for the origin of Las Cañadas caldera based on the current evidence gathered from all previous studies. © 2019 Elsevier B.V., I also thank Teide National Park for giving permission to undertake this research, which has been funded, among others by the EC grants TEIDE: European Laboratory Volcano, ERUPT, EXPLORIS (EVR1-CT-2002-40026), and VUELCO (FP7-ENV-2011 282729), and the Spanish grants MCyT TECTOTENE, MCyT FONOTEN, MEC TEGETEIDE (CGL2004-21643-E), MEC TENERISK (CGL-2006-13830), MEC PR-2006-0499, MICINN (CGL2010-11983-E), EXPLOTEI MICINN (CGL2008-04264), and MEC (CGL-2004-21247).