Eruption mechanism of Volcán de Colima: Is it moving towards a large destructive event?

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1 Eruption mechanism of Volcán de Colima: Is it moving towards a large destructive event? FONDO RAMON ÁLVAREZ-BUYLLA DE ALDANA Convocatoria 10 Octubre de 2008 Dr. Nicholas Varley Middle Facultad de Ciencias Domingo, 12 de Octubre de

2 DATOS DEL RESPONSABLE TÉCNICO: Título/grado y nombre: Dr. Nicholas Robert Varley Middle Nombramiento: Profesor Titular A Lugar de adscripción: Facultad de Ciencias Domicilio y teléfono laboral Facultad de Ciencias Universidad de Colima Bernal Díaz del Castillo # 340 Col. Villas San Sebastián, C.P Colima, Col. México Ext nick@ucol.mx Website: Domicilio y teléfono particular: Cóndor #79 Colinas de Santa Bárbara Colima, Col. CP Firma Datos del administrador de la unidad académica o de la DES que administrará el proyecto Nombre: C.P. Perla Gabriela Piña Araujo Teléfono: ext perlapia@ucol.mx Firma 2

3 1. RESUMEN EJECUTIVO 1.1 Planteamiento This project will assess the current activity of Volcán de Colima and determine the most efficient parameters from the monitoring network that can be used to forecast a future acceleration in activity. It is crucial that the relationship between the variety of parameters is understood and related to the physical processes in the system. The mechanism controlling degassing and explosivity is complex and requires detailed study. The project will build on results obtained as part of the project Improving the monitoring strategy at Volcán de Colima: modelling the explosive mechanism financed by FRABA in Certain parameters will be compared to better understand how energy is liberated from the volcanic system, which will lead to a model of the eruption mechanism considering the partition of energy between elastic or seismic, acoustic, thermal and kinetic. The behaviour of the eruption column in the atmosphere will also be addressed with the aim of better understanding the dispersion of tephra. Many theoretical models have been proposed to explain behaviour but few observations have been sufficiently well documented to verify these models. Data integration will permit verification and an improvement of the published theoretical models. 1.2 Justificación The current activity of Volcán de Colima is at the highest level since the last major eruption in Since 2003 it has shown continuous explosive activity with a frequency of explosions that has varied from between 1 or 2 events per day to 25 or more. There exists the possibility that the volcano has entered a pre-plinian stage, based on the following factors: a) The volcano has recently shown a cycle of one hundred years between major eruptions b) There is evidence that the activity during the period was similar to that in 2005 c) Geochemical evidence suggests that the composition of the magma is migrating towards a more explosive type The mechanism that produces the Vulcanian-type activity has yet to be established at Volcán de Colima. This type of activity is complex and non-linear: from the nucleation level in the conduit to the expulsion of material from the vent, the physics needs to consider a multiphase and unsteady system. With the expansion of the monitoring network in many new data are available. It is necessary to understand the correlation between different data types and to highlight the most critical parameters to detect an acceleration in activity which might culminate in a large Plinian eruption. It is clear that certain parameters have not shown a clear correlation during previous episodes, e.g. seismicity and pyroclastic flow run-out distance in Each volcano is unique which means a specific protocol needs to be established for the monitoring of each one. The hazard which is likely to have the largest impact in the event of a large (Plinian) eruption is ashfall, as was the case in The population affected by fallout of ash depends on the wind direction during an eruption. In 1913, Ciudad Guzmán, Jalisco suffered the largest impact. However, it is possible that the city of Colima be impacted during the next large event. To date, no modelling of tephra dispersal for Volcán de Colima has been carried out. It is crucial to understand the relationship between explosion mechanisms, and the production and dispersion of ash. 3

4 This project will help to address DEMANDA 4.2: Determinación de los riesgos y vulnerabilidad de zonas habitacionales, espacios públicos, infraestructura hotelera y edificios de valor histórico. 1.3 Descripción general del proyecto Various types of data will be compared to enhance current ideas for models of the volcanic system of Volcán de Colima. The infrasound network will be improved to provide better quality data. Software routines will be developed to analyse time series data, and a variety of statistical techniques will be employed to search for correlations among variable data sets. Numerical models of the complex multiphase systems that represent the volcanic conduit and eruption columns require various parameters for their solution. Observations and the data obtained will enable these parameters to be estimated and the models verified. The project includes various external collaborators, each having a specific area of expertise to supplement that available in Colima. The extensive high quality data set that will be obtained will offer ample opportunity for both presentation at international conferences and publication in international peer-reviewed journals. Various students will participate at undergraduate level and the project will provide them with the opportunity to experience scientific research, including equipment development and maintenance, and data collection and analyses. 4

5 2. OBJETIVO PRINCIPAL DEL PROYECTO Complex analyses are required of the extensive data set generated by the monitoring network of Volcán de Colima, in order to determine relationships which can be incorporated into models of the system. The project will develop the protocol for such analyses and define a model of the system. By understanding the eruption mechanism we will be able to better define the strategy for forecasting the next destructive eruption and determine the current and future volcanic risk in zones of habitation within the state. 5