LLUNPIY Simulations of the 1877 Northward Catastrophic Lahars of Cotopaxi Volcano (Ecuador) for a Contribution to Forecasting the Hazards

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.

Community Perception and Communication of Volcanic Risk from the Cotopaxi Volcano in Latacunga, Ecuador

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.