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Cotopaxi volcano is one of the most studied and surveyed volcanos in the world because the repetition of the 1877 catastrophic lahar invasion, is not implausible, threatening now more than 100,000 persons. A reliable forecasting tool is very important for projecting security measures. LLUNPIY is a Cellular Automata model for simulating lahars in te...
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... LLUNPIY (an acronym for Lahar modelling by Local rules based on an UNderlying PIck of Yoked processes, and comes from the Quechua word "llunp'iy", which means flood) is a three-dimensional model that delivers, in correspondence with each computational step and each CA cell, values of average altitude, lahar thickness, depth of erodible stratum, lahar outflows size, and kinetic head [8,14,15,[23][24][25][26]. To reliably simulate primary lahars, it is necessary to introduce well-defined mechanisms of the triggering process in the model. ...
... In this section, we briefly summarize the CA model on which the simulations of the Cotopaxi lahars, which flow along the upper Pastaza river, are based. Readers who are eager to obtain technical and mathematical knowledge about the model are invited to view the extensive bibliography on the subject [8,14,15,[23][24][25][26]29,30,32]. CA can be described as a space that is regularly partitioned into cells, each one embedding an identical input/output computing unit. ...
... Improved simulations [18] were carried out, taking into account the erosion and considering the lahar that was thus formed at the base of the volcano as the initial lahar. An "Instantaneous Melting" hypothesis, when the ice cap suddenly melting to a fixed depth occurs simultaneously with the eruption, underlies the simulations presented in [24,26]. As for the present study, the assumption that solely pyroclastic bombs are the melting triggers of the Cotopaxi ice cap is clearly a simplification of the actual process. ...
We forecast the impact that the lahars triggered on the summit of the Cotopaxi volcano in
Ecuador would have upon the Hidroagoyán Dam should an 1877-type catastrophic eruption occur
nowadays, with disastrous implications for the energy production of Ecuador. The Cotopaxi’ lahars
have been simulated with the use of different computational models, yet none of them were so
extended as to map their entire path to the dam. To fill this gap, we applied a version of the semiempirical
Cellular Automata LLUNPIY model to simulate primary and secondary lahars flowing
from the summit of the Cotopaxi volcano until they reach the Hidroagoyán Dam in Baños. This
version of LLUNPIY accounts for the triggering event by pyroclastic bombs and has already been
validated by its successful simulation of the northbound 1877 cataclysmic lahars of the Cotopaxi
volcano. The likely consequences of a similar disaster are discussed considering present territorial
conditions. Computer simulations of natural hazards of this type represent a powerful tool that can
be used when planning for the mitigation of environmental and social risks.
... Primary lahars are those originated The inclusion of the erosion process during the lahars' downstream motion represented a numerical breakthrough delivered by the adoption of a CA approach to the development of semiempirical computational models simulating surface flows [15]. The CA approach was actually derived from the previous SCIDDICA (Simulation through Computational Innovative methods for the Detection of Debris flow path using Interactive Cellular Automata) model [18][19][20][21] for the simulation of debris flows. Moreover, it constitutes a parallel computational paradigm for modeling complex dynamical systems, whose evolution is mainly due to the interactions among their constituent parts. ...
... The present LLUNPIY model (lahar modeling by local rules based on an underlying pick of yoked processes, from the Quechua word "llunp'iy", meaning flood) is based on the CA computational paradigm for simulating primary and secondary lahars according to a general methodology developed for surface flows [19]. LLUNPIY was applied and validated in its various versions to past volcanic events, such as the 2005 and 2008 secondary lahars of Vascún Valley, Tungurahua Volcano, Ecuador [20][21][22][23][24][25], as well as the 1877 lahars flowing along the Río Cutuchi, Cotopaxi Volcano [20], and it was also applied to forecast future probable events [26,27]. ...
... The present LLUNPIY model (lahar modeling by local rules based on an underlying pick of yoked processes, from the Quechua word "llunp'iy", meaning flood) is based on the CA computational paradigm for simulating primary and secondary lahars according to a general methodology developed for surface flows [19]. LLUNPIY was applied and validated in its various versions to past volcanic events, such as the 2005 and 2008 secondary lahars of Vascún Valley, Tungurahua Volcano, Ecuador [20][21][22][23][24][25], as well as the 1877 lahars flowing along the Río Cutuchi, Cotopaxi Volcano [20], and it was also applied to forecast future probable events [26,27]. ...
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.
... Approaches different from CA methods [16]have been adopted in order to model the behaviour of lahars and the risks posed to downstream communities [19]: PDE approximating numerical methods of complex physical behaviour of lahar [24], empirical models based on smart correlations of phenomenon observables [21,26], simple rheological and hydrological models, that assume acceptable simplifications as compositionindependent flow behaviour or Newtonian flow behaviour [5,22]. LLUNPIY (Lahar modelling by Local rules based on an UNderlying PIck of Yoked processes, from the Quechua word "llunp'iy" meaning flood) is a three-dimensions model, that returns for each computational step and for each CA cell values of average altitude, lahar thickness, depth of erodable stratum, lahar outflows size and velocity [13,14,16,17,18]. ...
... For the primary lahars, it is necessary to introduce in the model well defined mechanisms of triggering. In a previous version for primary lahars [18], the worst case of immediate melting of ice/snow by volcanic eruption was considered as triggering of primary lahars; the famous cataclysmic lahars of Cotopaxi Volcano (Ecuador) in 1877 were partially simulated and results were compared with available data of the real event. ...
... In order to model large scale natural systems (phenomena that are extended for kilometers) Macroscopic or Multicomponent CA (MCA) were developed as an extension of CA [10]; MCA permit to express physical macroscopic features of a cell as sub-states, e.g. sub-state altitude, whose value corresponds to the altitude of the portion of space corresponding to the cell [10]; M&S of surface flows by MCA permits to describe features of the third dimensions in terms of sub-states and permits to model efficaciously and efficiently many three dimensions phenomena by two dimensions MCA [1,2,7,8,9,12,13,14,15,16,17,18]. ...
Simulations1 of natural hazards by computer is a powerful tool to be used for mitigation of environmental risks. Here, we present our semi-empirical Cellular Automata model LLUNPIY for simulations of lahars and its extension to primary lahars. This version of LLUNPIY accounts for triggering by pyroclastic bombs and has been successfully validated by the simulations of the 1877 cataclysmic lahars of Cotopaxi Volcano (Ecuador); a likely occurrence of a similar disaster was simulated considering today's environmental conditions.
... Two MCA models were developed for flow-like landslide, SCIDDICA (several versions since 1987, e.g. [6][7][8][9][10][11][12]) for subaerial/subaqueous debris/mud/gra-nular flows and LLUNPIY for primary and secondary lahars [13][14][15]. ...
... SCIDDICA-SS2 [7,8,11], SCIDDICA-SS3 [9,10,12] and LLUNPIY [13][14][15] are our front-rank models for simulations of flow-like landslides. The extension of SCIDDICA-SS2 to urban areas and applied to Giampilieri events, could be introduced easily in SCIDDICA-SS3 that represents a more precise version, but involving long running times, or in LLUNPIY, an adaptation of SCIDDICA-SS3 to lahar features. ...
Different methodologies are used for modelling flow-like landslides. A critical point concerns the flooding of town areas, which cannot be assimilated straight to a morphology, especially, when the urban tissue is very irregular with narrow streets and setting of buildings, which reflect historical contingencies. SCIDDICA is a competitive (related to PDE approach) Cellular Automata model for 3-dimensions simulation of flow-like landslides. This paper presents innovations to the transition function of SCIDDICA-SS2, which manage opportunely building data in the cells corresponding to the urban tissue. That permits to simulate the complete evolution of landslides, from the detachment area to its exhaustion almost on the same precision level. This is an advantage for hazard and risk analyses in threatened zones. Improved SCIDDICA-SS2 was applied successfully to the well-known 2009 debris flows of Giampilieri Superiore also in comparison with simulation results of the previous versions.
... LLUNPIY model was applied to Cotopaxi 1877 event of primary lahars [33], after the successful simulation of some secondary lahars of Tungurahua volcano [14], [35]. We followed, as first approach, the "many sources" simplification proposed in Pistolesi et al. [34] that the main event could be equivalently generated, considering the initial positions of lahars sources in the three principal streams (Fig. 9): Río Cutuchi, Río Sasqìmala and Río Barrancas-Alaques. ...
Cellular Automata (CA) represent both abstract dynamical systems evolving on the base of local interactions of their constituent parts and a parallel computational paradigm for modelling complex phenomena, whose evolution may be explicated mostly in terms of local rules. CA represent a powerful tool for simulating
fluid-dynamical system; Macroscopic CA (MCA) characterize a methodological approach, which proved efficacious for modelling and simulating large scale surface flows. Fast-moving flow-like “landslides”, as lahars, debris and mud flows, give rise to very destructive natural disasters as number of casualties in the world. Simulation of such phenomena could be an important tool for hazard management in threatened regions. This paper presents the modelling methodology of MCA for such a type of surface flows together with
some models, based on this approach. They are SCIDDICA-SS2, SCIDDICA-SS3 (both for debris, mud and granular flows) and LLUNPIY (for primary and secondary lahars). Such models share certain features (common sub-states and elementary processes), while different specifications are introduced according to the peculiarities of related surface flows. Examples of simulations of both past (validation phase) and probable future events (developing hazard scenarios) are presented for each model. The last version of
LLUNPIY is here introduced with new applications to lahar hazard related to Ecuador’s volcanos Cotopaxi and Tungurahua.
... One of these is the city of Latacunga, which is located in the south-west valley and already destroyed in the 18th century (a village at that time) by volcanic activity [23,24]. LLUNPIY model was applied to Cotopaxi 1877 event of primary lahars [23], after the successful simulation of some secondary lahars of Tungurahua volcano [19,20]. We followed, as first approach, the "many sources" simplification proposed in [24] that the main event could be equivalently generated, considering the initial positions of lahars sources in the three principal streams (Fig.4): Río Cutuchi, Río Sasqìmala and Río Barrancas-Alaques. ...
Cellular Automata (CA) represent a computational paradigm for complex fluid-dynamical phenomena that evolve on the basis on local interactions. Macroscopic CA (MCA) characterize a methodological approach for modelling and simulating large scale (extended for kilometers) surface flows. Fast-moving flow-like “landslides”, as lahars, debris and mud flows, represent very destructive natural disasters as number of casualties in the world. Simulation of such phenomena could be an important tool for hazard management in threatened regions. This paper presents shortly the modelling methodology of MCA for such type of surface flow together with the models SCIDDICA-SS2, SCIDDICA-SS3 (both for debris, mud and granular flows) and LLUNPIY (for primary and secondary lahars) together with their significant applications in simulating both past and probable future events. At the end, a new result about possible hazard of Cotopaxi volcano is reported; the repetition of the 1877 catastrophic lahar invasion is simulated, beginning from the immediate melting of part of the Cotopaxi icecap because of volcanic activity.
... One of these is the city of Latacunga, which is located in the south-west valley and already destroyed in the 18th century (a village at that time) by volcanic activity [23,24]. LLUNPIY model was applied to Cotopaxi 1877 event of primary lahars [23], after the successful simulation of some secondary lahars of Tungurahua volcano [19,20]. We followed, as first approach, the "many sources" simplification proposed in [24] that the main event could be equivalently generated, considering the initial positions of lahars sources in the three principal streams (Fig.4): Río Cutuchi, Río Sasqìmala and Río Barrancas-Alaques. ...
Different methodologies are used for modelling flow-like landslides. A common critical point concerns the flooding into town areas, which cannot be assimilated straight to a morphology, especially, when the urban tissue is very irregular with narrow streets and odd setting of buildings, so that discretization processes of approximating numerical methods have to be carefully examined in their limits. A semi-empirical approach by the computational paradigm of cellular automata is here considered with SCIDDICA, a competitive (related to PDE approach) cellular automata model for 3-dimensions simulation of flow-like landslides. This paper presents innovations to the transition function of SCIDDICA-SS2, which manage opportunely building data in the cells corresponding to the urban tissue. The novelties of the transition function need a theorem, here demonstrated which regards the Algorithm of Minimization of Differences in the new context of inhomogeneous cells. This progress permits to simulate the complete evolution of landslides, from the detachment area to its exhaustion almost on the same precision level. This is an advantage for hazard and risk analyses in threatened zones. Improved SCIDDICA-SS2 was applied successfully to all the well-known 2009 debris flows of Giampilieri Superiore (Sicily) also in comparison with simulation results of the previous versions.
