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Cotopaxi volcano (elevation 5,897 m) seen from the north. In the foreground the Limpiopungo plain, with blocks carried by recent lahars. The main geographic locations are shown in the insets
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Cotopaxi volcano is situated in the Eastern Cordillera of the Ecuadorian Andes and consists of a symmetric volcanic cone that reaches an altitude of 5,897 m above sea level; it is capped over its upper 1,000 m by a permanent glacier. The volcano has erupted frequently in the past few centuries and, according to the archival records, has produced do...
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... the past centuries, large lahars (volcanic debris flows) associated with volcanic eruptions worldwide have repeatedly devastated human settlements (Hall 1992; Newhall and Punongbayan 1996; Rodolfo 1995; Tanguy et al. 1998; Voight 1990). For this reason, lahar studies represent a major focus of volcanic hazard assessment, as they are required for effective mitigation with respect to both civil protection and land-use planning. In particular, eruptions at ice-capped volcanoes often cause rapid melting of snow and ice and generate debris-flows that can severely impact valleys for hundreds of kilometers downstream from the source (Crandell 1971; Major and Newhall 1989; Pierson et al. 1990; Tanguy et al. 1998; Voight 1990). Field-based studies of past lahar sequences have been completed only for volcanoes where lahar hazard assessment and management are a prime target, e.g., Mt. Rainier and Mt. St. Helens in the Cascade Range (Hoblitt et al. 1998; Scott et al. 1995; Mullineaux and Crandell 1962; Pierson 1985), Ruapehu volcano, New Zealand (Cronin et al. 1997; Graettinger et al. 2010; Hodgson et al. 2007; Keigler et al. 2011; Lecointre et al. 2004), Merapi, Central Java (Lavigne et al. 2000), Popocatépetl, central Mexico (Capra et al. 2004), and previous work at Cotopaxi (Mothes et al. 2004). Studies of recent, well-observed debris flows (e.g., Kilgour et al. 2010; Pinatubo, Philippines, Rodolfo et al. 1996) allow the deposits to be linked to eruptive processes. Lahar assessment relies largely on numerical simulations (Barberi et al. 1992; Canuti et al. 2002; Carrivick et al. 2008; Davila et al. 2007; Darnell et al. 2012; Huggel et al. 2008; Macías et al. 2008; Muñoz-Salinas et al. 2009; Procter et al. 2010; Worni et al. 2011). With the exception of lahars formed during crater lake failures (Bornas et al. 2003; Manville and Cronin 2007; Manville 2010; Massey et al. 2010), however, there is little discussion in the literature about lahar-triggering mechanisms (exceptions include works by Fairchild 1987; Crandell 1971; Pierson 1985, 1995 and Scott 1985). At 5,897 m above sea level, Cotopaxi volcano ( Fig. 1) is heavily glaciated and has generated many devastating lahars; the socio-economic impact potential of future lahar- triggering eruptions is thus enormous. More specifically, ~100,000 people currently live in the flow path of lahars that were produced during the (relatively small) eruption of 1877. Additionally, major infrastructure and lifelines (including the Pan-American highway) have been constructed in probable lahar paths and would be inundated in the future by events comparable to that of 1877 (Mothes et al. 2004; Mothes 2006). Historical chronicles of the 1877 eruption (Sodiro 1877; Wolf 1878) document voluminous lahars that formed from scoria flows that spilled out of the crater and rapidly melted the ice cap. Since the glacier surface was about 1.3 times larger than present, recent numerical models of lahar hazards have used a 1877-magnitude event (Mothes et al. 1998, 2004; Pareschi et al. 2004) as a “ worst-case scenario ” . However, studies of the pyroclastic activity at Cotopaxi over the last eight centuries (Pistolesi et al. 2011) show that most of Cotopaxi ’ s explosive eruptions have triggered large lahars. We extend this work to provide a detailed analysis of individual lahar units as well as discuss the mechanism(s) by which eruptive phenomena have interacted with the summit glacier to produce lahars. We show that, over the past 800 years, the volcano has produced lahars that have varied greatly in magnitude. Within this spectrum, lahars associated with the 1877 event are intermediate in volume relative to large historical ( AD 1768, the largest for which eyewitnesses descriptions are available) and very large (twelfth to seventeenth century) lahars. We also highlight the relationship between different types of pyroclastic – density – current activity and mechanisms of rapid release of water and debris that form lahars. Lahar sequences characterized by the superposition of the deposits of multiple events are complex and present unique challenges to field study. First, distal lahar deposits are notoriously difficult to link to cogenetic lahar-generating tephras. In part, this reflects the lack of consistent litholog- ical and sedimentological features caused by downstream bulking (debris entrainment) and sediment deposition. Additionally, lahar deposits have very poor sorting and grain sizes that range from clay to meter-sized boulders and thus are difficult to characterize. Finally, facies analysis of laharic sequences has shown that a unique scheme of either vertical or lateral facies transitions cannot be unequivocally associated with a given lahar event (Vallance 2000). Traditionally, lahar stratigraphy and stratigraphic correlations of old debris-flow deposits have been delineated by careful comparison of radiocarbon dating, soil formation, clast characteristics, analysis of deposit, disposition in cross- sectional and longitudinal channel sections, and recognition of interlayered, dated tephra beds (Crandell 1971, 1987; Crandell and Mullineaux 1978; Donoghue and Neall 2001; Cronin and Neall 1997; Hodgson et al. 2007; Lecointre et al. 1998; Mullineaux 1974, 1986, 1996; Scott 1985). In rare cases, dendrochronology and lichenometry can provide constraints on the age of the deposits (Bollschweiler and Stoffel 2010; Crandell 1987; Pierson 2007; Roberts 2003; Scott et al. 1995; Waythomas et al. 2000). Here, we use classical tephrostratigraphy both to study lahar deposits and to establish the temporal relationship of lahar episodes to eruptive events at Cotopaxi. By comparing lahar- deposit sequences in two different morphological settings (a plateau at the northern base of the cone and a broad valley in the western sector of the edifice), we cross-checked results and tested the robustness of our conclusions. Importantly, we observed that very thin (millimeters) fall-out tephra beds survived the passage of lahars carrying meter-size boulders in large areas of the valley, probably because of a fast deceleration of flows coming from narrow, high-slope canyons as they entered in the flat, wider Cutuchi valley, which drains water to the south. This preservation is perhaps surprising, as thin bed preservation is most often associated with deposition along terraces and upslope of main valley channels, on overtopped terraces, or in back eddies. Tephrostratigraphic correlations allow us to associate lahar deposits of different origins with magnitude and type of the generating eruptive event, especially those with pyroclastic- flow activity, and to link triggering mechanisms to eruption style. Additionally, eyewitness observations made during the 1877 event constrain the timing of lahar generation. Importantly, Wolf (1878) described “ a dark foam-like cloud [that] boiled over the crater, much like the boiling over of a pot of cooking rice. ” As soon as the pyroclastic cloud overrode the glacier, lahars were triggered. In the words of other chroniclers, emplacement of scoria flows took ...
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Citations
... Locally overlying the 1877 BoAF deposits, there is a reddish block-rich debris flow deposit, rich in reworked bombs and with degassing pipes. Pistolesi et al. (2011Pistolesi et al. ( , 2013 interpreted the frequent occurrence of chilled margins around bombs as interaction of the juvenile hot material with ice and water. Pistolesi et al. (2011Pistolesi et al. ( , 2013 also described PDC deposits associated with the 1766-1768 and 1853 events, which are preserved on the northern and southern flanks of the volcano. ...
... Pistolesi et al. (2011Pistolesi et al. ( , 2013 interpreted the frequent occurrence of chilled margins around bombs as interaction of the juvenile hot material with ice and water. Pistolesi et al. (2011Pistolesi et al. ( , 2013 also described PDC deposits associated with the 1766-1768 and 1853 events, which are preserved on the northern and southern flanks of the volcano. These deposits partially fill the narrow gullies of the cone and spread over the flanks forming tongue-like deposits with low levées (Fig. 3D). ...
... During the Cotopaxi 1877 eruption, T. Wolf described the eruption -very probably related to PDCs-as generated by "a dark foam-like cloud that boiled over the rim of the crater and descended all sides of the cone, much like a pot of cooking rice boiling over". This boiling-over PDC-forming model has been proposed for the BoAF events at Cotopaxi (Andrade et al., 2005;Pistolesi et al., 2011Pistolesi et al., , 2013 and Fuego (Escobar, 2013). Also, some of the PDCs observed in 2006 and 2010 at Tungurahua were interpreted as having been generated by boilingover eruptions, one of which produced explosive fountaining but no significant convective plume. ...
Pyroclastic density currents with an abundance of cauliflower-shaped bombs are an uncommon type of deposit, called bomb and ash flow (BoAF) deposits in several papers. Although they are similar to block and ash flow (BAF) deposits (e.g., rich in juvenile blocks and breadcrusted bombs), they are often related to eruptions of mafic to intermediate magmas. In the current study, we analyze and compare historical and prehistorical BoAF-generating eruptions at Asama and Aso (Japan), Mayon (Philippines), Mt. Spurr (United States), Fuego (Guatemala), Arenal (Costa Rica), Cotopaxi and Tungurahua (Ecuador), and Láscar and Tilocálar volcanoes (Chile). Our review indicates that BoAFs show a substantial contribution of juvenile rounded material but with different rheologies and fragmentation mechanisms. This juvenile material is typically basaltic or andesitic, as it is more susceptible to form volcanic bombs with scoriaceous cauliflower textures. Thus, BoAFs could be a subset of the BAF deposits. The study and recognition of this type of deposit in volcanic sequences could be misinterpreted as a ballistic bomb deposit or even a hot bomb-rich lahar deposit, therefore, its appropriate interpretation is fundamental for volcanic hazard assessment.
... 0 • 41′S; long. 78 • 26′W) is the only volcano of this volcanic cluster whose Holocene activity has been thoroughly studied (Cotopaxi II edifice; e.g., Mothes et al., 1998;Hall and Mothes, 2008;Pistolesi et al., 2013;Tsunematsu and Bonadonna, 2015;Vezzoli et al., 2017;Sierra et al., 2019). Its eruptive history began with an ancient rhyolitic volcanic center (Cotopaxi I -Barrancas stage), whose products are preserved on Cotopaxi's present-day southern flank. ...
The unusually high number of volcanoes in the Ecuadorian Arc, located in the deformation zone of the continental North Andean Sliver, coincides with the projection of the major oceanic structures observed in the Nazca Plate, such as the Carnegie Ridge and the Grijalva fracture zone. Although the relationship between this tectonic setting and volcanism has been widely discussed in the literature, their temporal relationship has not been thoroughly investigated due to the lack of geochronological data. We present here 20 new Ksingle bondAr and 2 40Ar/39Ar ages obtained for 7 volcanoes of the central segment of the Ecuadorian arc, which together with previous data show that volcanism in this area started at ∼1.3 Ma. A notable increase in volcanic activity occurred since ∼0.6 Ma, when the formation of a dozen volcanoes occurred in a relatively small area of the central segment. While this arrangement of volcanoes, here referred to as a “volcanic cluster”, appears to be controlled by crustal tectonic structures, the order of onset of these volcanoes and their eruptive activity does not show clear migration patterns over time. However, the presence of older volcanoes in the north of the central segment suggests a possible southward extension of volcanism between ∼1.3 and ∼ 0.6 Ma. Finally, based on the cumulative bulk volumes calculated for the volcanic edifices over time, we infer that the magmatic productivity rate has been roughly constant during the last ∼550 kyr in this area.
... The Cotopaxi Volcano located in the western cordillera of the Ecuadorian Andes is known to have had a vast history of big eruptions, far-reaching ash emissions and most importantly lahar generations, which may surpass 150 million m 3 [14][15][16][17][18][19][20][21][22]. Lahar generation may be caused by either by the collapse of an eruptive column or by the effect known as boiling over, both produce pyroclastic flows, which are able to melt part of the glacier´s surface [15,18,19]. ...
... The Cotopaxi Volcano located in the western cordillera of the Ecuadorian Andes is known to have had a vast history of big eruptions, far-reaching ash emissions and most importantly lahar generations, which may surpass 150 million m 3 [14][15][16][17][18][19][20][21][22]. Lahar generation may be caused by either by the collapse of an eruptive column or by the effect known as boiling over, both produce pyroclastic flows, which are able to melt part of the glacier´s surface [15,18,19]. As the volcano awakens, it is fundamental to know the flow directions of the generated lahars in order to reduce risks, vulnerabilities and losses similar and/or worse than the ones that destroyed Armero town, Colombia in 1985 killing some 23,000 citizens [12,[23][24][25]. ...
The Cotopaxi Volcano is one of the most dangerous volcanoes world- wide due to its potential of the generation of voluminous lahars of dozens of mil- lions of cubic meters capable of destroying infrastructure and endangering a lot of people living near major river drainages of this volcano. Our study describes such circumstances in the northern side of Cotopaxi Volcano and how we pro- pose to reduce the vulnerability of the public with new evacuation methods. Therefore, we have used geomatic tools, in order to shorten evacuation ways and directions. Based on the results, we determined different spatial variables or geographic coverage of the described and highlighted the main points of interest in each of them. The location of initial evacuation points of the population was determined within the lahar travel area being along the road axes. With these points we calculated security checkpoints outside the area lahar with additional margin. For this process the impedance was determined according to the average speed of a person in case of evacuation. In areas where the evacuation time has been longer than the arrival time of the lahar, vertical rather than horizontal evacuation points were determined by evaluating its coverage area depending on the time needed for the population to be safe.
... Because of their origin during highly explosive events, primary lahars at Cotopaxi are a relatively infrequent phenomena, averaging less than one event per century over the past 800 years [6,17]. Thus, the lahar hazard at Cotopaxi has always been assessed by deterministic approaches, which have used different numerical models calibrated with Remote Sens. 2022, 14, 631 3 of 25 field data and corresponding lahar scenarios. ...
... It has been strongly suggested that the 1877 event may not represent the most likely nor the worst-case scenario for future eruptions of Cotopaxi [6,17]. However, it is the only one with some detailed and reliable historical accounts that help understanding the eruption evolution and its consequences [1,2]. ...
... These plains collect several different drainages descending through the deep gullies of Cotopaxi's middle and lower flanks, all of which are tributaries to the Rio Pita river (Figure 1). The 1877 lahar deposit, as well as several others, widely outcrop along these plains [6,17]. Given its extension, the study area has been divided into the following plains comprising specific drainages and morphologies: (1) Sindipamba; (2) Victor Punina (3) North-eastern; and (4) Eastern. ...
Cotopaxi is an active volcano in Ecuador, whose eruptions are characterized by producing destructive primary lahars which represent a major risk for the country. The hazard assessment related to such lahars relies largely on the knowledge of the latest event, which occurred on 26 June 1877, for either scenario definition or simulation calibration. A detailed (1:5000 scale) cartography of the deposits belonging to that eruption has been obtained in the proximal northern drainage of Cotopaxi. The cartography was performed through a combination of geological fieldwork, as well as the analysis and interpretation of high-definition imagery obtained by drone surveys combined with the Structure from Motion technology for image processing. Such imagery included red and green visible bands, and a near-infrared band, which allowed the obtention of NDVI imagery where the primary lahar deposits were identified and cartographed with support of fieldwork data. Both data sources are mutually complementary, and the final cartography would be impossible if any of them were not available. The results obtained represent a significant advance for the level of detail with respect to previous cartographic works. Moreover, they should allow an improved calibration of the new generation of numerical models that simulate lahar flow for hazard assessment at Cotopaxi.
... Syn-eruptive lahars occurred frequently during the explosive activity of Cotopaxi volcano and the larger were triggered by the rapid melting of large amounts of ice during eruptions [17]. The most violent historical eruptions occurred in 1744, 1768, 1877, and 1904, all of them causing disastrous lahars [16,17]. ...
... The presence of a permanent glacier on the upper cone is one of the principal causes, together with volcanic eruptions (lava or pyroclastic flows and surges), of primary lahars, triggered by ice and snow melting [5,16,27,31]. The present Cotopaxi eruptive episode started in August 2015 and is still ongoing. ...
LLUNPIY (lahar modeling by local rules based on an underlying pick of yoked processes, from the Quechua word “llunp’iy“, meaning flood) is a cellular automata (CA) model that simulates primary and secondary lahars, here applied to replicate those that occurred during the huge 1877 Cotopaxi Volcano eruption. The lahars flowing down the southwestern flanks of the volcano were already satisfactorily simulated in previous investigations of ours, assuming two possible different triggering mechanisms, i.e., the sudden and homogeneous melting of the summit ice and snow cap due to pyroclastic flows and the melting of the glacier parts hit by free-falling pyroclastic bombs after being upwardly ejected during the volcanic eruption. In a similar fashion, we apply here the CA LLUNPIY model to simulate the 1877 lahars sprawling out the Cotopaxi northern slopes and eventually impacting densely populated areas. Our preliminary results indicate that several important public infrastructures (among them the regional potable water supply system) and the Valle de Los Chillos and other Quito suburban areas might be devastated by northward-bound lahars, should a catastrophic Cotopaxi eruption comparable to the 1877 one occur in the near future.
... Some of the most representative and better-exposed stratigraphic formations of ancient ashes and lahar deposits originated from the previous volcanic activity of the Cotopaxi volcano were visited ( Figure 3) with the guidance of experts from the Geophysical Institute of the National Polytechnic School (IG-EPN (Instituto Geofísico de la Escuela Politécnica Nacional (Quito, Ecuador))) and the Decentralized Autonomous Government of the Province of Cotopaxi (GADPC (GADPC, Gobierno Autónomo Descentralizado Provincial de Cotopaxi, Latacunga, Ecuador)). Some of these deposits are from pre-historical times, whilst the shallower ones date from the 1877 event that destroyed Latacunga [70]. Official maps of the Geological and Energy Research Institute (IIGE) and IG-EPN [71] were used during the field reconnaissance. ...
The inhabitants of Latacunga living in the surrounding of the Cotopaxi volcano (Ecuador) are exposed to several hazards and related disasters. After the last 2015 volcanic eruption, it became evident once again how important it is for the exposed population to understand their own social, physical, and systemic vulnerability. Effective risk communication is essential before the occurrence of a volcanic crisis. This study integrates quantitative risk and semi-quantitative social risk perceptions, aiming for risk-informed communities. We present the use of the RIESGOS demonstrator for interactive exploration and visualisation of risk scenarios. The development of this demonstrator through an iterative process with the local experts and potential end-users increases both the quality of the technical tool as well as its practical applicability. Moreover, the community risk perception in a focused area was investigated through online and field surveys. Geo-located interviews are used to map the social perception of volcanic risk factors. Scenario-based outcomes from quantitative risk assessment obtained by the RIESGOS demonstrator are compared with the semi-quantitative risk perceptions. We have found that further efforts are required to provide the exposed communities with a better understanding of the concepts of hazard scenario and intensity.
... The last 2100 years at Cotopaxi II have witnessed repetitive andesitic eruptions characterised by the deposition of lava flows, regional tephra layers and large-scale syneruptive lahars (Pistolesi et al., 2011;Pistolesi et al., 2013). Average recurrence periods between 117 and 147 years may be estimated for Cotopaxi eruptions (Barberi et al., 1995), though it has been shown that the occurrence of eruptions displays significant clustering (Pistolesi et al., 2011). ...
... Primary lahars formed during explosive eruptions undoubtedly represent the most hazardous phenomena at the Cotopaxi (Pistolesi et al., 2013;Mothes et al., 2016aMothes et al., , 2016bSierra et al., 2019). These flows are formed during explosive eruptions, when pyroclastic density currents move on top of the volcano glacier and melt it, instantaneously producing large volumes of water quickly mixing with volcanic rocks (Pistolesi et al., 2013). ...
... Primary lahars formed during explosive eruptions undoubtedly represent the most hazardous phenomena at the Cotopaxi (Pistolesi et al., 2013;Mothes et al., 2016aMothes et al., , 2016bSierra et al., 2019). These flows are formed during explosive eruptions, when pyroclastic density currents move on top of the volcano glacier and melt it, instantaneously producing large volumes of water quickly mixing with volcanic rocks (Pistolesi et al., 2013). These flows transit through the three main drainage systems descending from the volcano (Figure 1): Rio Pita to the north, Rio Cutuchi to the south and the Rio Tambo to the east. ...
Lahars are among the most hazardous mass flow processes on earth and have caused up to 23,000 casualties in single events in the recent past. The Cotopaxi volcano, 60 km southeast of Quito, has a well‐documented history of massively destructive lahars and is a hotspot for future lahars due to (i) its ~10 km² glacier cap, (ii) its 117‐147‐year return period of (Sub)‐Plinian eruptions and (iii) the densely populated potential inundation zones (300,000 inhabitants). Previous mechanical lahar models often do not (i) capture the steep initial lahar trajectory, (ii) reproduce multiple flow paths including bifurcation and confluence, and (iii) often fail to generate appropriate key parameters like flow speed and pressure at the base as a measure of erosion capacity. Here, we back‐calculate the well‐documented 1877 lahar using the RAMMS debris flow model with an implemented entrainment algorithm, covering the entire lahar path from the volcano edifice to an extent of ~ 70 km from the source. To evaluate the sensitivity and to constrain the model input range, we systematically explore input parameter values, especially the Voellmy‐Salm friction coefficients μ and ξ. Objective selection of most likely parameter combinations enables a realistic and robust lahar hazard representation. Detailed historic records for flow height, flow velocity, peak discharge, travel time and inundation limits match best with a very low Coulomb‐type friction μ (0.0025‐0.005) and a high turbulent friction ξ (1000‐1400 m/s²). Finally, we apply the calibrated model to future eruption scenarios (Volcanic Explosivity Index = 2‐3, 3‐4, > 4) at Cotopaxi and accordingly scaled lahars. For the first time, we anticipate a potential volume growth of 50‐400% due to lahar erosivity on steep volcano flanks. Here we develop a generic Voellmy‐Salm approach across different scales of high‐magnitude lahars and show how it can be used to anticipate future syneruptive lahars.
... The major volcanic hazard has been lahars, which result usually by the emplacement of pyroclastic flows generating a partial melting of the surface area of the glacial cover at its peak. Such lahars have historically devastated natural drainage areas in the northern, eastern and southern surrounding of the volcano, claiming lives and infrastructure [11][12][13][14]. ...
... The volcano Cotopaxi, which is located some 33 km northeast of Latacunga, has a vast and detailed studied eruptive history, with a varied generation of strong eruptive phases with VEI´s of up to 5 and volcanic hazards, which include fall-out and precipitations of pyroclastic material, pyroclastic flows and far-reaching lahars [19][20][21][22][23]. The main hazards with a high potential of destruction and life-loss are lahars, with an estimated total volume of up to 36 0 million m 3 , corresponding to the natural drainages of the rivers Cutuchi (180 millions of m 3 ), Saquimala (90) and Barracas-Aláquez (90) [13]. The recurrence time of catastrophic emplacements of lahars has been calculated to be every 117 ± 70 years, of which last event dated in 1877 [11,12]. ...
The current economic study has been performed about a territorial analysis in the area of potential lahars flows from the Cotopaxi volcano within the city of Latacunga, central Ecuador. We have used as inputs the plan of development and land-use planning 2016-2028, studies concerning this topic and field data obtained from surveys to the affected properties, consulting on variables of typology of the construction, use of the land and economic through a property study. The use of geographic information systems over such information allowed to obtain results in order to determine the human losses by lahar risks, to quantify the surface and estimate the affected population and probable death toll. Furthermore , it determines the economic losses by lahars in Latacunga, and quantify the total value of losses in the event of an eruption of Cotopaxi, and finally, it proposes the relocation in safe areas of the inhabitants at high and medium risk, estimating the cost of relocation versus the application of mitigation measures, specifically engineering works.
... Traditional grain size measurements are commonly more accurate (error ranges in the literature between 0 and 17% with an average of 3%) for fine fractions of unlithified clastic deposits because such material can be measured using techniques including sieving (10 −6 -10 1 m) or a particle analyzer (10 −9 -10 1 m) (e.g., Wohl et al., 1996;Shaw et al., 2010;Román-Sierra et al., 2013;Pistolesi et al., 2013;Zawacki et al., 2019). The size of large particles is often estimated through less accurate (error ranges between 4 and 19% with an average of 11%) measurements, including point counting with hand measurements for larger clasts (>10 −3 m) (Wohl et al., 1996). ...
... Surveys of coarse-grained volcaniclastic deposits, including grain size measurements, can enhance our understanding of depositional processes. Pistolesi et al. (2013) showed that coarse-grained lahar deposits could be correlated with distinct phases of eruptive activity on Cotopaxi Volcano. Beyond volcaniclastic deposits, D'Arcy et al. (2017) showed a remarkable relationship between the grain size of debris flow deposits in Owens Valley California and climate fluctuations as recorded by the benthic Pacific δ 18 O stack. ...
Volcaniclastic stratigraphy can be difficult to map and describe due to its complex nature. However, such stratigraphy preserves information about fluctuations in volcanic activity and sedimentation and is vital to understanding volcanic systems. Uncrewed aerial vehicle (UAV) based analysis of volcanic stratigraphy can enhance mapping and analysis, especially on vertical surfaces where outcrop exposure is greatest. Here we present a method for using small UAVs to produce vertical grain size and bedding measurement logs, or quantitative stratigraphic columns, of vertical volcaniclastic stratigraphy. We demonstrate the range of high-accuracy measurements and parameters that can be collected for building measurement logs using consumer grade UAVs through a case study in the Marysvale volcanic field where we collected 34,422 grain measurements from 21 individual units. The purpose of producing such measurement logs is to enhance lithofacies analysis through the use of large quantitative datasets and improve the reproducibility of data reporting. Whereas descriptions of volcaniclastic units such as those describing grading are often reported qualitatively, we describe methods for calculating numerical parameters for enhanced lithologic analysis including grain size, grading, clast to matrix ratios, and shape characteristics. The methods described in this paper can enhance field data acquisition, mapping, and quantitative analysis of volcaniclastic deposits and are applicable to a wide range of other geologic settings where coarse-grained clastic sedimentary deposits exist.
... In the current study, we have analyzed the current economic effects of potential lahars from Ecuador's Cotopaxi volcano. This volcano, which has been categorized as being one of the most dangerous volcanoes in the world (Miller et al. 1978;Barberi et al. 1995), is located in the northern volcanic Andes and is known to have had a vast history of lahar generations due to explosions reaching a Volcanic Explosivity Index of 4-5 (Barberi et al. 1995;Aguilera et al. 2004;Aguilera and Toulkeridis 2005;Pistolesi 2008;Pistolesi et al. 2013Pistolesi et al. , 2014Toulkeridis 2013;Toulkeridis et al. 2015). Past historical eruptions have had devastating impact in the areas surrounding Cotopaxi in 1534, 1742, 1768 and 1877, in which lahars destroyed important areas towards the northern and southern sides of the volcano and to a lesser extent towards its eastern area (La Condamine 1751;Sodiro 1877;Whymper 1892;Wolf 1878;Mothes 1992;Barberi et al. 1995;Aguilera et al. 2004;Garrison et al. 2011;Pistolesi et al. 2013Pistolesi et al. , 2014. ...
... This volcano, which has been categorized as being one of the most dangerous volcanoes in the world (Miller et al. 1978;Barberi et al. 1995), is located in the northern volcanic Andes and is known to have had a vast history of lahar generations due to explosions reaching a Volcanic Explosivity Index of 4-5 (Barberi et al. 1995;Aguilera et al. 2004;Aguilera and Toulkeridis 2005;Pistolesi 2008;Pistolesi et al. 2013Pistolesi et al. , 2014Toulkeridis 2013;Toulkeridis et al. 2015). Past historical eruptions have had devastating impact in the areas surrounding Cotopaxi in 1534, 1742, 1768 and 1877, in which lahars destroyed important areas towards the northern and southern sides of the volcano and to a lesser extent towards its eastern area (La Condamine 1751;Sodiro 1877;Whymper 1892;Wolf 1878;Mothes 1992;Barberi et al. 1995;Aguilera et al. 2004;Garrison et al. 2011;Pistolesi et al. 2013Pistolesi et al. , 2014. The aforementioned references describe in detail the trajectory and impact sites of the lahars as well as their volumes and velocities. ...
Abstract The recent awakening of the Cotopaxi volcano in Ecuador set the conditions to estimate and verify the possible effects of potential lahars on residential housing unit prices. About 300,000 people live in the Los Chillos valley, which is the northern natural drainage of Cotopaxi’s lahars; therefore, the effects on house values can be significant. We have used housing information from 2016 of 240 properties to settle a hedonic price model within and outside of the lahar’s area. The regression model has a significant R2 value of about 0.723. The variable that determined the effects of potential lahar on the hedonic model demonstrates that the value of a residence house unit will increase its price by 41.99 USD for each meter away from the lahar path. Our study suggests that environmental disamenities generated by natural hazards will have a negative effect on residential house unit prices and we infer that consumers would be willing to pay a higher price in order to avoid such potential disamenities.
