Lava Dome Morphology and Viscosity Inferred From Data-Driven Numerical Modeling of Dome Growth at Volcán de Colima, Mexico During 2007-2009

Magma extrusion, lava dome growth, collapse of domes, and associated pyroclastic flow hazards are among important volcanological studies. In this paper, we analyze the influence of the magma viscosity and discharge rates on the lava dome morphology at Volcán de Colima in Mexico during a long dome-building episode lasting from early 2007 to fall 2009 without explosive dome destruction. Camera images of the lava dome growth together with recorded volumes of the erupted lava have been used to constrain numerical modeling and hence to match the history of the dome growth by nudging model forecasts to observations. Our viscosity model incorporates crystal growth kinetics and depends on the characteristic time of crystal content growth (or CCGT) and the crystal-free magma viscosity. Initially, we analyze how this viscosity, CCGT, and the rate of lava extrusion influence the morphology of the growing dome. Several model scenarios of lava dome growth are then considered depending on the crater geometry, the conduit location, the effective viscosity of dome carapace, and the extrusion rates. These rates are determined either empirically by optimizing the fit between the morphological shape of modeled domes and that of the observed dome or from the recorded lava dome volumes. The maximum height of the modeled lava dome and its horizontal extent are in a good agreement with observations in the case of the empirically-derived extrusion rates. It is shown that the topography of the crater at Volcán de Colima is likely to be inclined toward the west. The viscosity of the modeled lava dome (∼1012 Pa s) is in a good agreement with the effective viscosity estimated experimentally from lavas of Volcán de Colima. Due to the interplay between the lava extrusion and the gravity forces, the dome reaches a height threshold, and after that a horizontal gravity spreading starts to play an essential role in the lava dome evolution. The model forecasts that the dome carapace of higher viscosity (∼1014 Pa s) influences the dome growth and its morphology during long dome-building episodes by retarding horizontal advancement and developing steep-sided eastern edge of the dome at the volcano. The developed model can be used in assessments of future effusive eruptions and lava dome growth at Volcán de Colima or elsewhere. History matching modeling of lava dome growth sheds a light on dynamic processes inside the dome and may assist in assessing stress state in the dome carapace and in forecasting the dome failures.

Aplicación de VolcFlow para simular Avalanchas de Escombros y CDP en los volcanes Popocatépetl, Volcán de Colima y Ceboruco

El análisis de los peligros volcánicos permite cuantificar el potencial de riesgo sobre eventos históricos en un contexto social y económico. Por su ubicación geográfica, México cuenta con al menos 38 centros volcánicos, incluyendo volcanes monogenéticos y estratovolcanes, que han presentado actividad explosiva en los últimos 10 mil años. Entre los más relevantes se encuentra el volcán Popocatépetl, Volcán de Colima y Ceboruco que mantienen diversas similitudes entre sí, como presentar actividad explosiva reciente y ubicarse sobre una región con una densidad de población y, por tanto, alto grado de vulnerabilidad. En este contexto, el volcán Ceboruco ha presentado al menos 8 erupciones en los últimos 1000 años, siendo la última la erupción más relevante la de 1870. De igual manera, Volcán de Colima y Popocatépetl han sido dos de los volcanes más activos de México con frecuente emplazamiento y destrucción de domos de lava en los últimos 20 años. La actividad explosiva de ambos volcanes ha provocado la evacuación preventiva en diversas ocasiones por parte de autoridades correspondientes. Para nuestro análisis, hemos utilizado el código VolcFlow, escrito en MATLAB, que resuelve las ecuaciones de conservación de masa y momento para el análisis de dispersión y alcance de los flujos. El presente artículo muestra los resultados del análisis de la modelación de diversos peligros volcánicos como son lahares, flujos piroclásticos y avalanchas de escombros con enfoque hacia la mitigación de riesgo volcánico. Los resultados nos permiten realizar modificaciones efectivas sobre los parámetros reológicos que son característicos para cada tipo de peligro volcánico en cada volcán considerando las características particulares como es densidad de flujo, la viscosidad, volumen de material emitido y por supuesto, Modelo de Elevación Digital.

Evidence of the Early Holocene eruptive activity of Volcán de Colima and the 8.2 kyr global climatic event in lacustrine sediments from a debris avalanche-dammed lake

Volcán de Colima, one of the most active volcanoes in Mexico, experienced at least nine flank failures during the last 30,000 years, with catastrophic effects on the environment that implies the formation of temporary dams where lacustrine sediments accumulated for hundreds of years. These lacustrine sequences preserve an exceptional record from which to reconstruct the effect of subsequent volcanic eruptions and, eventually, contemporary environmental and climatic conditions. Here we analyze an Early Holocene lacustrine sequence, named “Gypsum King”, which accumulated in a short-lived temporary lake, likely formed by emplacement of the 10755-11230 cal. yr BP Mesa-Yerbabuena debris avalanche. Through detailed analysis of the 1.8 m thick lacustrine sequence (14C ages, sulfur content, grain size), it was possible to identify the 8.2 kyr global climate event and better constrain the Early-Holocene main sub-plinian to plinian eruptions of Volcán de Colima. The results presented here highlight the potential to explore sulfur content and abrupt change in grainsize in lacustrine sediments as additional proxies to better constrain eruptive phases in volcanic environments. Finally, the Gypsum King sequence provides the first evidence of the 8.2 kyr global climate event along the Eastern tropical Pacific Coast.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5563424

Insights Into the Internal Dynamics of Natural Lahars From Analysis of 3-Component Broadband Seismic Signals at Volcán de Colima, Mexico

Lahar monitoring on active volcanoes is challenging, and the ever changing environment leads to inconsistent results that hamper a warning systems ability to characterize the flow event properly. Therefore, more data, new methods, and the use of different sensors needs to be tested, which could lead to improvements in warning capabilities. Here, we present data from a 3-component broadband seismometer and video camera installed 3 m from the Lumbre channel on Volcán de Colima, Mexico to understand rheology differences within multiple lahar events that occurred in late 2016. We examine differences in frequency and directionality from each seismic component. Results indicate an increase in peak frequency above background in each component when a lahar nears the sensor, and a decrease in overall peak frequency when transitioning from a streamflow to a higher concentration flow. The seismic frequency distribution for the cross-channel component for the streamflow has a wider range compared with the lahar events. In contrast, the peak spectral frequency of the streamflow is narrower in comparison to the lahar events in the flow parallel and vertical directions. Estimated directionality ratios (cross-channel signal divided by flow parallel signal) yielded further evidence for a rheologic change between streamflow and lahars. Directionality ratios >1 were calculated for each lahar, and <1 for streamflow. Finally, we demonstrate from component analyses that channelization or freedom of movement in the cross-channel, bedload transport in the flow parallel, and bed composition in the vertical directions are possibly the main drivers in the peak spectral frequency output of lahars. The results described here indicate that using all three components may provide important information about lahar dynamics, which may be useful for automatic detection and warning systems, and using all three components should be encouraged.