Pyroclastic deposits and eruptive heterogeneity of Volcán Antuco (37°S; Southern Andes) during the Mid to Late Holocene (&lt;7.2 ka)

Romero, Jorge E.; Ramirez, Victoria; Alam, Mohammad Ayaz; Bustillos, Jorge; Guevara, Alicia; Urrutia, Roberto; Pisello, Alessandro; Morgavi, Daniele; Criollo, Evelyn

doi:10.1016/j.jvolgeores.2019.106759

Cited by 7 publications

(5 citation statements)

References 81 publications

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“…Recent investigations highlighted the role of volcanic eruptions (Zingaretti et al, 2023), GLOFs (Wilson et al, 2019; Bahamondes et al, 2022), wildfires (Iroumé et al, 2015) and landslides (Sepúlveda et al, 2015) on fluvial dynamics, and Mazzorana et al (2019) highlighted how these can also trigger process cascades resulting in complex geomorphic adjustments. The Antuco Volcano located in the upper part of the study basin erupted at least 27 times from 1,624 to 1939 (Romero et al, 2020), some of which involved pyroclastic flows and tephra deposition, and while no records exist on the impact of the Laja River's evolution, it is reasonable to expect effects similar to those observed after the 2008 Calbuco Volcano eruption (Iroumé et al, 2015).…”

Section: Discussionmentioning

confidence: 96%

Synergistic process interactions and morphological change in a river reach subject to multiple disturbances, the Laja River, Chile

Barahona,

Alcayaga,

Caamaño

et al. 2024

Earth Surf Processes Landf

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This work studies the multiple sources of impacts and disturbances in the Laja River (Central Chile) and evaluates the changes in water and sediment flows and planimetric geomorphic changes.The disturbances sources correspond to hydroelectric plants, water withdrawals for irrigation and the sustained decrease trend in rainfall in the basin. The changes in the plan‐view shape of the river reach were quantified using remote sensing techniques, through a supervised classification of Landsat 5 TM and 8 OLI satellite images, identified Water (W), Islands and Riverine Vegetation (IRV) and Bars and Banks Without Vegetation (BBWV), obtained a Kappa index>0,83 for a period of 15 years (2006–2021).Compared with historical records, the period of analysis shows a decrease in annual rainfall by 17.5%. In addition, water withdrawals for irrigation have contributed to a 64% decrease in monthly stream discharge during the dry season. As a consequence of the decrease in annual rainfall and water withdrawals for irrigation, the sediment transport capacity has also decreased by 10.5%.The changes in morphological driving variables (stream flows and sediment transport regimes) have manifested themselves in morphological changes, where it was possible to establish that a change in the channel form occurred in the last 15 years, going from a river with a single channel to a braided one. An important vegetation establishment has accompanied this morphological change on both riverbanks and the central bars. The colonizing vegetation corresponds to fast‐growing non‐native species (Salix spp., Populus spp. and Alnus spp). A stabilization of the channel form is expected, consolidating itself as a braided section with alternating vegetated bars.

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Section: Discussionmentioning

confidence: 96%

Synergistic process interactions and morphological change in a river reach subject to multiple disturbances, the Laja River, Chile

Barahona,

Alcayaga,

Caamaño

et al. 2024

Earth Surf Processes Landf

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“…At the Laguna del Maule volcanic complex, for example, at least three Plinian eruptions, three moderate explosive eruptions (i.e., VEI 3-4) and one ignimbrite-forming eruption, all younger than 14 ka, were identified (Fierstein et al, 2013). Further south, the tephrostratigraphic record at Antuco volcano revealed 23 mid-to-late Holocene explosive eruptions, three of them with sub-Plinian characteristics (Romero et al, 2020b). Similarly, 27 <12 ka-old tephra deposits were described by Gilbert et al (2014) at Lonquimay volcano.…”

Section: Recognising Past Explosive Eruptionsmentioning

confidence: 92%

The Andean Southern Volcanic Zone: a review on the legacy of the latest volcanic eruptions

Romero,

Vergara-Pinto,

Forte

et al. 2024

andgeo

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The Andean Southern Volcanic Zone (SVZ) concentrates many of the most active volcanoes of the Andean continental arc, as well as the region’s most recent and impactful volcanic eruptions. In this contribution, we briefly revise the general characteristics of the SVZ volcanism and provide a synthesis of the scientific findings related to the latest volcanic eruptions (430 peer-reviewed publications with over 9,000 citations, with large-magnitude (VEI 4-5) eruptions being the most studied. Our study shows that SVZ research has been primarily focused on environmental and atmospheric impacts (29%), eruption descriptions and physical volcanology (20%), volcanic hazard and risk assessments (15%), and other investigations complementary to volcanology. Whereas the least silicic eruptions (e.g., Llaima 2008-2009 and Villarrica 2015) shed light on magma replenishment and degassing dynamics controlling eruption styles, intermediate eruptions (andesitic-dacitic) offered clues on either rapid or slow eruption initiation, with relevant findings on phreatic-to-magmatic style transitions and eruption triggering mechanisms. On the other hand, silicic (i.e., rhyolite-rhyodacite) eruptions provided unique observations on rapid magma ascent, high-rate magma extrusion, rheology, fragmentation processes, and style transitions. These recent eruptions have also inspired a new generation of tephrochronological, tephrostratigraphical, and physical volcanology studies, aimed at assessing the long-term (kyr-scale) evolution of the volcanic systems and their associated hazards. We debate how the knowledge gained from research and the long-term human coexistence with volcanoes are relevant to reducing volcanic risk in the SVZ. Finally, we discuss how challenges and opportunities emerging from other disciplines can complement our understanding of volcanism in this active region.

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“…y BP according to our radiocarbon dating. Simultaneously, between 4.4 and 3.5 ky BP El Pino sub-Plinian tephra fallout affected the eastern side of the volcano (Romero et al 2020), thus indicating a dominant explosive behavior of Antuco soon after the lateral collapse. Further volcanic activity was characterized by a high effusive flux (0.65-0.94 km 3 kyr −1 ), about twice that of the pre-collapse stage (see Martinez et al 2018), allowing the rapid cone regeneration in a few thousand years.…”

Section: Age Of the Collapse And Impactsmentioning

confidence: 99%

“…Normal faults beneath volcanoes produce unstable flanks which are normal to sigma 1, to the dyke injections strike, and which affect the cone flanks that are in extension (Mathieu et al 2011). Despite any syn-collapse earthquake being preserved, some of these extensional structures have shown to be active during at least the last 3 kyr BP and to have generated seismites in the SW margin of Laja Lake which were interpreted as caused by M W ~ 5 earthquakes by Romero et al (2020). Also, mafic dyke intrusions during eruptions may induce large increases in the pore pressure, leading to instability, but also volcano-tectonic seismicity that may reach M W 4-6 (Romero et al 2021b and references therein).…”

Section: Triggering Factorsmentioning

confidence: 99%

Mid-Holocene lateral collapse of Antuco volcano (Chile): debris avalanche deposit features, emplacement dynamics, and impacts

Romero

Moreno²,

Polacci

et al. 2022

Landslides

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Antuco (37.4°S, 71.4°W; Chile) is a dominantly basaltic stratovolcano whose original ~ 3300 m altitude main cone experienced a catastrophic sector collapse at ~ 7.1 cal ka BP, producing a volcanic debris avalanche deposit (VDAD) with hummocky surface and ~ 6.4 km3 of volume. We carried out geological studies of its debris avalanche deposit, which was distributed to the W and displays a longitudinal facies transformation from edifice’s megablocks and block to mixed facies in distal areas (up to 25 km from the scar). Our observations support the behavior of the avalanche beginning as a translational slide, and then as plug flow when confined within the Laja River valley. Clay abundance and high content of hydrothermally altered material may suggest active participation of water; flow velocities are estimated to ~100 m s−1. We primarily identify the steep-sided flanks of the cone, and hydrothermal alteration promoted the edifice instability, while basement seismogenic structures may have ultimately triggered the landslide. Subsequent landslide-led events include the transformation of the volcanic activity with explosive eruptions producing a sequence of dilute pyroclastic density currents (PDCs) ending ~3.4 ky BP, and extensive lava effusion rapidly reconstructing the collapsed edifice. Moreover, the Antuco VDAD also blocked the natural output of the Laja Lake, increasing its level by ~200 m and then triggering cataclysmic outburst floods by dam rupture, preserved as high-energy alluvial beds with ages between 2.8 and 1.7 ky BP. The Antuco constitutes an excellent example of a critical chain of events initiated by a stratovolcano lateral collapse and warns for detailed hazard investigations to better comprehend its related impacts.

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Pyroclastic deposits and eruptive heterogeneity of Volcán Antuco (37°S; Southern Andes) during the Mid to Late Holocene (<7.2 ka)

Cited by 7 publications

References 81 publications

Synergistic process interactions and morphological change in a river reach subject to multiple disturbances, the Laja River, Chile

Synergistic process interactions and morphological change in a river reach subject to multiple disturbances, the Laja River, Chile

The Andean Southern Volcanic Zone: a review on the legacy of the latest volcanic eruptions

Mid-Holocene lateral collapse of Antuco volcano (Chile): debris avalanche deposit features, emplacement dynamics, and impacts

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