HR: 1400h
AN: V33A-02    [Abstracts]
TI: A Statistical Method for Volcanic Hazard Assessment: Applications to Colima, Popocatepetl and Citlaltepetl Volcanoes, Mexico.
AU: * Mendoza-Rosas, A T
EM: ateresa@geofisica.unam.mx
AF: Posgrado en Ciencias de la Tierra, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, D.F 04510, Mexico
AU: De la Cruz-Reyna, S
EM: sdelacrr@geofisica.unam.mx
AF: Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, D.F 04510, Mexico
AB: The volcanic-eruption time series are sequences describing processes of great complexity representing one of the main tools for the assessment of the volcanic hazard. The analysis of such series is thus a critical step in the precise assessment of the volcanic risk. The study of low-magnitude eruption sequences, containing larger data populations can usually be done using conventional methods and statistics, namely the Binomial or Poisson distributions. However, time-dependent processes, or sequences including rare or extreme events involving very few data, require special and specific methods of analysis, such as the non-homogeneous Poisson process analysis or the extreme-value theory. A general methodology for analyzing these types of processes is proposed in this work with the purpose of calculating more precise values of the volcanic eruption hazard. This is done in four steps: First, an exploratory analysis of the repose-periods and eruptive magnitudes series is done complementing the historical eruptive time series with geological eruption data and thus expanding the data population. Secondly, a Weibull analysis is performed on the repose-time between successive eruptions distribution. Thirdly, the eruption occurrence data are analyzed using a non-homogeneous Poisson process with a generalized Pareto distribution as its intensity function. Finally, these results are compared with fittings obtained from conventional Poisson and Binomial distributions. The hazard or eruption probabilities of three active polygenetic Mexican volcanoes: Colima, Popocatepetl and Citlaltepetl are then calculated with this method and compared with the results obtained with other methods.
DE: 8404 Volcanoclastic deposits
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
DE: 8486 Field relationships (1090, 3690)
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly