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2 Volcanic hazard map with restricted access zones (evacuation and exclusion) used during the Calbuco 2015 eruption (Hazard extents from Moreno (1999), evacuation extents from Mella et al. (2016)).
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This report presents data and summarises the findings of a reconnaissance trip investigating the impacts of the April 2015 eruption of Calbuco volcano, Chile, undertaken in November- December 2016. This study is mostly focused on the Los Lagos region, focusing on impacts occurring within ~30 km of the volcano, which includes the tourism town of Pue...
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... volcanic arc of the southern Andes is the product of subduction of the Nazca plate underneath the South American plate at a velocity of 7-9 cm/yr ( Stern et al., 2007). There are 90 geologically active volcanoes in mainland Chile, mostly located in the Central and Southern Andes (Figure 3.1; Global Volcanism Program (GVP), 2013a). ...
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... main hazards associated with the volcano are: tephra (mainly to the east), lava flows (< 9 km in length), pyroclastic flows of varying size, including those generated by collapse or lateral explosion, ballistics, and cold and hot lahars (Moreno, 1999;Moreno et al., 2006; Moreno and Gibbons, 2007; Figure 3.2). The most affected areas to tephra are located to the northeast, east and southeast of the volcano (Moreno, 1999). ...
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... the 2015 eruption of Calbuco, the monitoring network consisted of two seismic stations deployed near and far field, one visual camera and one electronic tiltmeter. Following the 2015 Calbuco eruption, the monitoring network was expanded, and at the time of our visit consisted of six seismic stations, three visual cameras, one electronic tiltmeter and one infrasound sensor (Figure 3.3). ...
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... formed in all major drainages around the volcano (Figure 3.3). The lahars in the south were both syn-and post-eruptive, whilst those in the north were post-eruptive secondary lahars. ...
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... mostly affected the area northeast of the volcano (Figure 3.4). Tephra thicknesses of 20-30 cm were deposited in Ensenada, about 15 km to the northeast of the volcano. ...
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... September 2015, the exclusion zone was reduced again to include only an area of restricted access towards the summit of the volcano (Figure 4.3). The location of this restricted access zone was based on identification of areas that are above the 1500 m elevation zone and within flow hazard zones. ...
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... For instance, the presence of lava domes can stimulate the formation of explosive eruptions via gas accumulation in the conduit (e.g., Alfano et al. 2011;Surono et al. 2012;Maeno et al. 2019) and/or unpredictable PDCs via dome collapse, without any precursory sign (e.g., Shimizu 2022; Breard et al. 2023). While direct plume-forming eruptions may cause a real-time hazard and significant human disruption over large areas (e.g., Hayes et al. 2019;Williams et al. 2020). ...
Ten rock samples consisting of one pyroclastic density current (PDC1) deposit, seven lava flows (LF1–7), and two summit lava domes (LD1, 2) were studied to understand the petrogenesis and magma dynamics at Mt. Sumbing. The stratigraphy is arranged as LF1, PDC1, LF2, LF3, LF4, LF5, LF6, LF7, LD1, and LD2; furthermore, these rocks were divided into two types. Type I, observed in the oldest (LF1) sample, has poor MgO and high Ba/Nb, Th/Yb and Sr. The remaining samples (PDC1–LD2) represent type II, characterized by high MgO and low Ba/Nb, Th/Yb and Sr values. We suggest that type I is derived from AOC (altered oceanic crust)-rich melts that underwent significant crustal assimilation, while type II originates from mantle-rich melts with less significant crustal assimilation. The early stage of type II magma (PDC1–LF3) was considered a closed system, evolving basaltic andesite into andesite (55.0–60.2 wt% SiO2) with a progressively increasing phenocryst (0.30–0.48 \(\upphi_{PC}\)) and decreasing crystal size distribution (CSD) slope (from − 3.9 to − 2.9). The evidence of fluctuating silica and phenocryst contents (between 55.9–59.7 wt% and 0.25–0.41 \(\upphi_{PC}\), respectively), coupled with the kinked and steep (from − 5.0 to − 3.3) CSD curves imply the interchanging condition between open (i.e., magma mixing) and closed magmatic systems during the middle stage (LF4–LF6). Finally, it underwent to closed system again during the final stage (LF7–LD2) because the magma reached dacitic composition (at most 68.9 wt% SiO2) with abundant phenocryst (0.38–0.45 \(\upphi_{PC}\)) and gentle CSD slope (from − 4.1 to − 1.2).
... Such tephra fallouts will be deposited on the roofs, providing load pressure on the buildings underneath (i.e., dwellings, and public infrastructures). Significant roof collapse is likely to occur if the load pressure (from tephra fall deposits) exceeds the maximum load capacity (MLC), making the impacted buildings becomes non-reparable (e.g., Hayes et al. 2019). Therefore, in this section, we attempted to constrain the susceptible zone from pyroclastic fall deposits by identifying areas with the highest probability of roof collapse. ...
... Thus, we suggest that any buildings within 7.7-22.1 km radius distances from the summit (under various tephra conditions, i.e., dry, wet, and saturated) are facing significant potential roof collapse, thus must be immediately evacuated and restricted if another VEI 3-4 eruptions were to occur at Sumbing volcano. Finally, it is significant that our recommendation regarding distances (SZ) is similar to the other VEI 3 and 4 eruptions, such as the 2015 CE eruptions of Cotopaxi (Ecuador) and Calbuco (Chile), where the restricted area reaches 20 km radius from the vent (equivalent to > 20 cm tephra thickness; Biass and Bonadonna 2011, Hayes et al. 2019. The fact that buildings inside the 20 km radius suffered extensive damage (from non-reparable to moderately reparable) also supports this idea (see Fig. 5.2. in Hayes et al. 2019). ...
This study documents the first record of seven-, Quaternary (<27.4 - >1.1 ka) lapilli fall layers at Sumbing volcano, Central Java, Indonesia. These lapilli layers (from lower towards upper stratigraphic height) are named orange–red lapilli, dark brown lapilli, orange lapilli, red–brown lapilli, blackish brown lapilli, pale red lapilli, and red lapilli. All deposits were dominated by juvenile scoria (Cscoria\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{scoria}$$\end{document} = 54–96%) with various portions of volcanic lithics (Clithics\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{lithics}$$\end{document} = 4–44%). The products were dispersed across a wide area (400–2149 km² for 1 cm isopach), suggesting sub-Plinian to Plinian intensity, with mean eruption plumes reaching 15–28 km and volcano explosivity index (VEI) of 3–4. The deposition of tephra (lapilli) on the roof provides load pressure, thus threatening buildings from collapse. No significant bulk density (ρbulk\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\uprho }_{bulk}$$\end{document}) variation between each lapilli deposit (690–813 kg/m³ for dry tephra, 856–1007 kg/m³ for wet tephra, and 1208–1422 kg/m³ for saturated tephra). Thus, tephra thickness (h\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$h$$\end{document}) is believed to play the most significant role in controlling load pressure (P=ρbulk×h\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$P = {\uprho }_{bulk} \times h$$\end{document}), as it varies over three orders of magnitude (< 1–100 cm). Finally, under the assumption that all-nearby settlements followed the national standard for maximum load capacity (MLC; 487 kg/m²), we proposed three susceptible zones (SZs). The estimated radius for SZ I (representing dry tephra condition) is ~7.7 km and ~14.6 km for VEI 3 and 4 eruptions, respectively. If tephra becomes wet and/or even saturated with water due to heavy rain (which is likely to occur in tropical regions such as the present case), the estimated radius increases to ~12.7 km and ~15.3 km (VEI 3), and ~17.7 km and ~22.1 km (VEI 4) for SZ II and SZ III, respectively. These areas must be evacuated immediately if VEI 3–4 eruptions were to occur at Sumbing volcano.
... The most recent eruption of the Calbuco volcano occurred in April 2015 ( Figure 2); it was sub-Plinian, with a Volcanic Explosivity Index (VEI) of 4 [54][55][56]. It generated pyroclastic density currents, lahars, and tephra fall, causing many impacts in Chile and Argentina such as damage to infrastructure, and agricultural and livestock activities, as well as suspending regional air traffic for a few weeks [57]. The tephra mostly affected areas northeast of the volcano (Figure 1), such as the Ensenada village nearly 15 km away, which was covered by tephra deposits of 20-30 cm thick [54]. ...
... The most recent eruption of the Calbuco volcano occurred in April 2015 ( Figure 2); it was sub-Plinian, with a Volcanic Explosivity Index (VEI) of ~4 [54][55][56]. It generated pyroclastic density currents, lahars, and tephra fall, causing many impacts in Chile and Argentina such as damage to infrastructure, and agricultural and livestock activities, as well as suspending regional air traffic for a few weeks [57]. The tephra mostly affected areas northeast of the volcano (Figure 1), such as the Ensenada village nearly 15 km away, which was covered by tephra deposits of 20-30 cm thick [54]. ...
The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with nega-tive impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a better understanding of its eruptive frequen-cy. We developed a continuous eruptive record of Calbuco for the 1514–2016 period by dendro-chemical analysis of Fitzroya cupressoides tree rings at a biennium resolution using inductively coupled plasma–mass spectrometry. After comparing the chemical record of 20 elements con-tained in tree rings with historical eruptions, one group exhibited positive anomalies during (Pb/Sn) and immediately after (Mo/P/Zn/Cu) eruptions, with a Volcanic Explosivity Index (VEI) ≥ 3, and so were classified as chemical tracers of past eruptions (TPE). The tree-ring width chronol-ogy also exhibited significant decreases in tree growth associated with eruptions of VEI ≥ 3. Ac-cording to these records, we identified 11 new eruptive events of Calbuco, extending its eruptive chronology back to the 16th century and determining a mean eruptive frequency of ~23 years. Our results show the potential to use dendrochemical analysis to infer past volcanic eruptions in Northern Patagonia. This information provides a long-term perspective for assessing eruptive history in Northern Patagonia, with implications for territorial planning.
... Together with Villarrica and Llaima, Calbuco is one of the most hazardous and active volcanoes in the Southern Andes as witnessed by its recurrent explosivity and its 2015 sub-Plinian eruption that caused significant damage to the local communities and disrupted Chilean and Argentinean air traffic. This eruption had also severe economic consequences for one of Chile's key salmon-farming and agricultural area (Hayes et al. 2019). Calbuco is a truncated-cone shaped stratovolcano located on the southern shore of lake Llanquihue in the Central Southern Volcanic Zone (CSVZ, 41°20' S) (Fig. 1). ...
The recurrent explosive eruptions of Calbuco (Andean Southern Volcanic Zone (SVZ)) threat a rapidly expanding touristic and economic region of Chile. Providing tighter constraints on its magmatic system is therefore important for better monitoring its activity. Calbuco is also distinguished by hornblende-bearing assemblages that contrast with the anhydrous parageneses of most Central SVZ volcanoes. Here we build on previous work to propose a detailed petrological model of the magmatic system beneath Calbuco. Geochemical data acquired on a hundred samples collected in the four units of the volcano show no secular compositional change indicating a steady magmatic system since ~ 300 ka. A tholeiitic Al2O3-rich (20 wt. %) basalt (Mg# = 0.59) is the parent magma of a differentiation trend straddling the tholeiitic/calc-alkaline fields and displaying a narrow compositional Daly gap. Amphibole crystallization was enabled by the higher H2O content of the basalt (3–3.5 wt. % H2O at 50 wt. % SiO2) compared to neighboring volcanoes. This characteristic is inherited from the primary mantle melt and possibly results from a lower degree of partial melting induced by the mantle wedge thermal structure. Although macrocrysts are not all in chemical equilibrium with their host rocks and were thus presumably unlocked from the zoned crystal mush and transported in the carrier melt, the bulk-rock trend follows both experimental liquid lines of descent and the chemical trend of calculated melts in equilibrium with amphibole (AEMs). These contradictory observations can be reconciled if minerals are transported in near cotectic proportions. The AEMs overlap the Daly gap revealing that the missing liquid compositions were present in the storage region. Geothermobarometers all indicate that the chemical diversity from basalt to dacite was acquired at a shallow depth (210–460 MPa). We suggest that differentiation from the primary magma to the parental basalt took place either in the same storage region or at the MOHO.
... Consequently, the descriptions of the Los Venados inhabitants' experiences of psychological stress and anxiety during compulsory evacuation periods are associated with leaving their livestock and houses alone. Similar findings have been identified in other contexts of Southern Chile (Wilson et al., 2009;Major and Lara, 2013;Hayes et al., 2019b). For example, during the 2008 Chaitén eruption (Sandoval, 2017), people resisted the post-evacuation relocation from their territory that had being declared uninhabitable (Larenas, 2014). ...
Human societies have inhabited volcanic zones since times immemorial, but only recently scientists and decision-makers have turned the attention to the study of such dwellings, aiming at reducing major risks and impacts involved. There is growing consensus about the importance of integrating natural and social sciences approaches and engaging with local communities. Nevertheless, such integration and dialogue among local actors, scientists and decision-makers is usually difficult to achieve. We present the case of the Rayün Yallel indigenous community, inhabiting in-between two mayor volcanic systems (Carrán Los Venados and Puyehue-Cordón Caulle), to explore their experience in relation with past and recent eruptions; to analyze the connections between the local communities’, scientists and decision-makers; and to identify gaps and potentials for risk reduction and livelihoods in volcanic environments. Results show that people have relied on the land and its resources over time, developing a sense of place with and a body of knowledge about volcanoes. But recent eruptions have challenged community perceptions of risk, showing fragmented and limited understanding of eruptions and disconnection with science and policy. Findings stress the potentials of interdisciplinary integration and the need for enhanced volcanic risk and hazard communication and community preparedness.
... To collect the required information, we conducted semi-structured interviews with officials from organisations involved with the response to the eruption and residents affected by the eruption in both Chile and Argentina. Interviews were conducted as part of a larger research project assessing the impacts from the Calbuco 2015 eruption on infrastructure, facilities, primary industries, and public health (see Hayes et al. 2019a). The project was reviewed and approved by the University of Canterbury Human Ethics Committee (Ref: HEC 2016/69/LR-PS). ...
... The permanent population of Ensenada is approximately 4000, but during the tourism season (December-February) it can increase to over 10,000. Ensenada was evacuated when Calbuco erupted in April 2015 (Hayes et al. 2019a). Route 225 was affected by up to 20 cm of tephra from the eruption, which was only accessible by 4WD vehicles (Hayes et al. 2019a). ...
... Ensenada was evacuated when Calbuco erupted in April 2015 (Hayes et al. 2019a). Route 225 was affected by up to 20 cm of tephra from the eruption, which was only accessible by 4WD vehicles (Hayes et al. 2019a). Consequently, a priority of the emergency response was to restore road connectivity between Puerto Varas and Ensenada for evacuation purposes (Hayes et al. 2019a). ...
Reliable methods for volcanic impact and risk assessments are essential. They provide constructive information to emergency and disaster managers, critical infrastructure providers, the insurance industry, and wider society. Post-eruption clean-up of tephra deposits is a prevalent and expensive (time and resource) activity which is often not planned for. Here, we present an overview of the clean-up efforts undertaken in four communities after the VEI 4 eruption of Calbuco volcano in 2015. We narratively reconstruct clean-up efforts in Ensenada (Chile), Junín de los Andes (Argentina), San Martín de los Andes (Argentina), and Villa La Angostura (Argentina) using semi-structured interviews, syn-and post-deposition photographs, pre-and post-event visual spectrum satellite imagery, and media reports. We compare these reconstructions with estimates based on a geospatial modelling approach adapted from Hayes et al. (Journal of Applied Volcanology 6:1; 2017). Specifically, we compare reported and geospatially derived estimates for volume of tephra removed, and clean-up operation duration. Our modelling approach performed well for Junín de los Andes but did not adequately capture volume and clean-up operation duration for the three remaining case study locations. We discuss several sources of uncertainty (including observational errors and natural variance of tephra deposit thickness), reported tephra removal volume estimates, clean-up methods, land use, and temporal evolution of clean-up operation demand. Our work demonstrates the utility of using simple geospatial data to develop assessments for tephra clean-up for use in response and recovery planning, and quantitative volcanic impact and risk assessments.
... In response to first (and second) phase of the eruption, a 20 km evacuation zone was implemented, based on the risk of potential pyroclastic density currents (Mella et al., 2016;Hayes et al., 2019). However, four days after phase 1, property and business owners were permitted access to some areas in Ensenada between 08:00-17:00 to collect belongings and clear ash from roofs to prevent damage (Hayes et al., 2019). ...
... In response to first (and second) phase of the eruption, a 20 km evacuation zone was implemented, based on the risk of potential pyroclastic density currents (Mella et al., 2016;Hayes et al., 2019). However, four days after phase 1, property and business owners were permitted access to some areas in Ensenada between 08:00-17:00 to collect belongings and clear ash from roofs to prevent damage (Hayes et al., 2019). As more information about the eruption was collected and interpreted and eruptive activity subsided, the evacuation zone was reduced to 10 km 6 weeks after the eruption initiation, allowing much of Ensenada to be reoccupied (Mella et al., 2016;Hayes et al., 2019). ...
... However, four days after phase 1, property and business owners were permitted access to some areas in Ensenada between 08:00-17:00 to collect belongings and clear ash from roofs to prevent damage (Hayes et al., 2019). As more information about the eruption was collected and interpreted and eruptive activity subsided, the evacuation zone was reduced to 10 km 6 weeks after the eruption initiation, allowing much of Ensenada to be reoccupied (Mella et al., 2016;Hayes et al., 2019). However, most of the settlements south of the volcano remained evacuated due to limited evacuation routes and persistent lahar risk (Hayes et al., 2019). ...
Assessing the damage to buildings from volcanic eruptions is an important aspect of volcanic risk assessment and management. However, there is a limited empirical evidence base to draw upon when describing the relation between volcanic hazard intensity and resulting physical damage. The 2015 subplinian eruption of Calbuco volcano, Chile, caused damage to buildings near the volcano because of tephra fall and lahars. Chilean authorities conducted a damage assessment of 961 properties (990 buildings) to inform an assistance programme for property owners affected by the eruption. Property assessments typically contained observations and classification of damage to a house, and in some instances accessory buildings such as sheds, garages, and exterior storage rooms. In this study we used this unique damage data set to adapt damage state frameworks for tephra fall and lahar for classifying and analysing damage observations. We developed data quality indicators to provide transparency for how we accounted for data quality issues. We assigned a tephra and/or lahar damage state to 571 buildings (530 houses and 41 accessory buildings). The 419 buildings for which we did not assign a damage state either had too little information or fell outside of tephra and/or lahar hazard zones. The minimum tephra thickness isopach band that caused complete collapse was 10 to 15 cm (dry deposit loading ~1 to 1.6 kN m−2, saturated deposit loading 1.6 to 2.4 kN m−2), but most commonly (55% of tephra exposed DS5 houses n = 11), this occurred at 15 to 30 cm (dry deposit loading ~1.5 to 3.3 kN m−2, saturated deposit loading 2.4 to 4.8 kN m−2). Lahar damage was typically described as complete (DS5), with 26 houses being swept away or destroyed around the Blanco South River. Our results add to the limited evidence base of post-eruption tephra and lahar impacts to buildings and contribute to volcanic risk and impact assessment.
Developing approaches to assess the impact of tephra fall to agricultural and forestry systems is essential for informing effective disaster risk management strategies. Fragility functions are commonly used as the vulnerability model within a loss assessment framework and represent the relationship between a given hazard intensity measure (e.g., tephra thickness) and the probability of impacts occurring. Impacts are represented here using an impact state (IS), which categorises qualitative and quantitative statements into a numeric scale. This study presents IS schemes for pastoral, horticultural, and forestry systems, and a suite of fragility functions estimating the probability of each IS occurring for 13 sub-sectors. Temporal vulnerability is accounted for by a ‘seasonality coefficient,’ and a ‘chemical toxicity coefficient’ is included to incorporate the increased vulnerability of pastoral farming systems when tephra is high in fluoride. The fragility functions are then used to demonstrate a deterministic impact assessment with current New Zealand exposure.
