Impact of tephra falls on Andean communities: The influences of eruption size and weather conditions during the 1999–2001 activity of Tungurahua volcano, Ecuador

Pennec, Jean–Luc Le; Ruiz, G.; Ramón, Patricio; Palacios, Enrique; Mothes, Patricia; Yépes, Hugo

doi:10.1016/j.jvolgeores.2011.06.011

Cited by 63 publications

(54 citation statements)

References 39 publications

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“…Prior to the 1999-ongoing phase, historical eruptions have occurred in 1640, 1773, 1886and 1916-1918(Hall et al 1999. Since 1999, the eruptive activity has varied between violent Strombolian to Vulcanian style explosions with associated pyroclastic flows, lava jetting and weaker explosions with ash emissions (Le Pennec et al 2011;Fee et al 2010;Ruiz et al 2005). Pyroclastic flows are of particular concern to communities on the volcano's western and northern flanks, including the large town of Baños (Hall et al 1999).…”

Section: Tungurahuamentioning

confidence: 99%

“…Pyroclastic flows are of particular concern to communities on the volcano's western and northern flanks, including the large town of Baños (Hall et al 1999). Tephra fall has and continues to have impacts on communities in the region, including Baños and nearby cities (Le Pennec et al 2011) (Tobin & Whiteford 2002), and lahars pose a persistent hazard even during periods of quiescence (Williams et al 2008).…”

Section: Tungurahuamentioning

confidence: 99%

“…Initial activity was phreatic, then magmatic as of the 11 th October 1999 (Le Pennec et al 2011). An evacuation of the town of Baños and surrounding communities (faldas) was called by the President of Ecuador on 16 th October (Tobin & Whiteford 2002).…”

Section: Evacuation Of Baños and Surrounding Faldasmentioning

confidence: 99%

“…An evacuation of the town of Baños and surrounding communities (faldas) was called by the President of Ecuador on 16 th October (Tobin & Whiteford 2002). Activity increased to include violent Strombolian and small Vulcanian explosions from the 28 th October, with the first eruptive phase lasting until 10 th December 1999 (Le Pennec et al 2011). Many people from Baños worked in the tourism industry, and those from surrounding communities in agriculture.…”

Section: Evacuation Of Baños and Surrounding Faldasmentioning

confidence: 99%

“…Interviewees repeatedly commented that the continued volcanic activity, which has posed a threat to the communities since 1999, gave the network a strong sense of purpose (Le Pennec et al 2011). …”

Section: Motivations Of the Vigías In The Early Networkmentioning

confidence: 99%

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Risk reduction through community-based monitoring: the vigías of Tungurahua, Ecuador

et al. 2014

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Since 2000, a network of volunteers known as vigías has been engaged in community-based volcano monitoring, which involves local citizens in the collection of scientific data, around volcán Tungurahua, Ecuador. This paper provides the first detailed description and analysis of this well-established initiative, drawing implications for volcanic risk reduction elsewhere. Based on 32 semi-structured interviews and other qualitative data collected in June and July 2013 with institutional actors and with vigías themselves, the paper documents the origins and development of the network, identifies factors that have sustained it, and analyses the ways in which it contributes to disaster risk reduction. Importantly, the case highlights how this community-based network performs multiple functions in reducing volcanic risk. The vigías network functions simultaneously as a source of observational data for scientists; as a communication channel for increasing community awareness, understanding of hazard processes and for enhancing preparedness; and as an early warning system for civil protection. Less tangible benefits with nonetheless material consequences include enhanced social capital -through the relationships and capabilities that are fostered -and improved trust between partners. Establishing trust-based relationships between citizens, the vigías, scientists and civil protection authorities is one important factor in the effectiveness and resilience of the network. Other factors discussed in the paper that have contributed to the longevity of the network include the motivations of the vigías, a clear and regular communication protocol, persistent volcanic activity, the efforts of key individuals, and examples of successful risk reduction attributable to the activities of the network. Lessons that can be learned about the potential of community-based monitoring for disaster risk reduction in other contexts are identified, including what the case tells us about the conditions that can affect the effectiveness of such initiatives and their resilience to changing circumstances.

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Section: Tungurahuamentioning

confidence: 99%

Section: Tungurahuamentioning

confidence: 99%

Section: Evacuation Of Baños and Surrounding Faldasmentioning

confidence: 99%

Section: Evacuation Of Baños and Surrounding Faldasmentioning

confidence: 99%

Section: Motivations Of the Vigías In The Early Networkmentioning

confidence: 99%

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Risk reduction through community-based monitoring: the vigías of Tungurahua, Ecuador

et al. 2014

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Mass budget partitioning during explosive eruptions: insights from the 2006 paroxysm of Tungurahua volcano, Ecuador

Bernard

Eychenne

Pennec

et al. 2016

Geochem Geophys Geosyst

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International audienceHow and how much the mass of juvenile magma is split between vent-derived tephra, PDC deposits and lavas (i.e., mass partition) is related to eruption dynamics and style. Estimating such mass partitioning budgets may reveal important for hazard evaluation purposes. We calculated the volume of each product emplaced during the August 2006 paroxysmal eruption of Tungurahua volcano (Ecuador) and converted it into masses using high-resolution grainsize, componentry and density data. This data set is one of the first complete descriptions of mass partitioning associated with a VEI 3 andesitic event. The scoria fall deposit, near-vent agglutinate and lava flow include 28, 16 and 12 wt. % of the erupted juvenile mass, respectively. Much (44 wt. %) of the juvenile material fed Pyroclastic Density Currents (i.e., dense flows, dilute surges and co-PDC plumes), highlighting that tephra fall deposits do not depict adequately the size and fragmentation processes of moderate PDC-forming event. The main parameters controlling the mass partitioning are the type of magmatic fragmentation, conditions of magma ascent, and crater area topography. Comparisons of our data set with other PDC-forming eruptions of different style and magma composition suggest that moderate andesitic eruptions are more prone to produce PDCs, in proportions, than any other eruption type. This finding may be explained by the relatively low magmatic fragmentation efficiency of moderate andesitic eruptions. These mass partitioning data reveal important trends that may be critical for hazard assessment, notably at frequently active andesitic edifices

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Sigmoidal particle density distribution in a subplinian scoria fall deposit

Eychenne

Pennec

2012

Bull Volcanol

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International audienceA general expression to describe particle density distribution in tephra fall deposits is essential to improve fallout tephra mass determination and numerical modelling of tephra dispersion. To obtain particle density distributions in tephra fall deposits, we performed high-resolution componentry and particle density analyses on samples from the 2006 subplinian eruption of Tungurahua volcano in Ecuador. Six componentry classes, including pumice and scoria, have been identified in our sample collection. We determined the class of 300 clasts in each 0.5ϕ fractions from −4.5ϕ to 3.5ϕ and carried out water pycnometry density measurements on selected size fractions. Results indicate that the mean particle density increases with ϕ up to a plateau of ~2.6 g/cm3 for clasts finer than 1.5ϕ. The density of scoria and pumice increases between −3 and 1ϕ, while dense particle density is sub-constant with grainsize. We show that the mean particle density μ of the vesicular fractions is a function of grainsize i (ϕ scale) given by a sigmoidal law: μ(i)=K+β/(1+αe−ri) , where K, β, α and r are constants. These sigmoidal distributions can be used to determine accurately the load of each componentry class and should be applicable to many tephra deposits and for modelling purposes

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Impact of tephra falls on Andean communities: The influences of eruption size and weather conditions during the 1999–2001 activity of Tungurahua volcano, Ecuador

Cited by 63 publications

References 39 publications

Risk reduction through community-based monitoring: the vigías of Tungurahua, Ecuador

Risk reduction through community-based monitoring: the vigías of Tungurahua, Ecuador

Mass budget partitioning during explosive eruptions: insights from the 2006 paroxysm of Tungurahua volcano, Ecuador

Sigmoidal particle density distribution in a subplinian scoria fall deposit

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