Engaging Students in Active Learning 35

Hazard mitigation practical: Predicting a volcanic eruption

A5.

Phil Gravestock

This exercise was designed to help students to understand some of the methods used to predict volcanic eruptions. It simulates the position that a volcanologist might be in while interpreting incomplete data from a range of sources and having to make quick interpretations and decisions. Students are highly motivated and appreciate insights into aspects such as timescales and human issues. Along with an understanding of some prediction techniques, it introduces a number of important social concepts such as the communication of the threats posed by potential hazards to the local residents, and the evacuation of villages (e.g. How will they be evacuated? Where will they be evacuated? What emergency procedures will need to be put in place?). General description The exercise is based around activity reports for four volcanoes, with each group of students tackling a different volcano. When using this exercise with groups containing more than 35-40 students it may be necessary to have different groups assessing the same volcano, although I generally give them different numbers so that it is not obvious that the volcanoes are the same. I have found that the optimum group size is 6-8 students. The timing of events are based upon real eruptions: volcano 1 is based on the Pinatubo eruption of 1991; volcano 2 on the Krakatau eruption of 1883; volcano 3 on the 1991-1993 eruption at Mount Etna (although in this practical it doesn't erupt); and volcano 4 is based upon a mixture of the Japanese volcano Unzen (1991 pyroclastic flow eruption) and Mount St Helens (1980). The students are provided with: a hazard zonation map; a list of alert levels and possible indications of the sort of activity that may be associated with each level (from Ewert & Newhall, no date); and a summary chart for recording their decisions. Prior to this exercise, the students will need to have been given information about sulphur dioxide measurements using a

36 Geography Discipline Network

correlation spectrometer (COSPEC), gravity measurements, harmonic tremors and gas emissions from volcanic flanks (although these are all at a fairly basic level). Each group designates one student member who will collect the activity reports. Subsequent reports will only be given on submission of the previous decisions and students should therefore keep a record of the date of the previous report, the alert level, evacuations etc. on the Summary Sheet. It is also important to make sure that the students cannot see how many activity reports are remaining, as this will affect their decision on when the final eruption will take place (it is tempting for the students to interpret some of the precursor activity as leading to an imminent eruption). In order to maintain 'stress' levels it is useful to put pressure on slower groups this often leads to hurried, rash decisions. I have found that common errors are for students to:

evacuate villages too quickly go to a high alert level too quickly try to lower the alert level too quickly allow people to return to villages when it appears that volcanic

activity has decreased. Consolidating the learning Possible options for consolidating the learning gained by completing the exercise include:

Presentations in which the groups outline their decisions and their reasons for their choices. This can then be followed by a self-evaluation of their success, or otherwise, in predicting the eruption, communicating information to the local residents, and evacuating the villages. Other students are encouraged to challenge the group about their decisions.

Combining two groups to discuss their actions and any revisions they would make in hindsight; this works particularly well if the groups have been working on the same volcano.

The discussions can also include consideration of techniques which may be used to mitigate the effects of volcanic eruptions.

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Evaluation Students often comment that they had not fully appreciated the time-scale involved in the build-up to some eruptions, or the fact that it is not always possible to have all the information required to make an accurate prediction. Variation A variation to this exercise is to get the student groups to generate their own hazard zonation maps, prior to providing the activity reports. Some additional information about the nature of each volcano would need to be provided to allow the students to devise reasonable maps. References Ewert, J.W. & Newhall, C.N. (no date) Volcanic crisis in the Philippines: the 1991 eruption of Mount Pinatubo [online]. Available at (accessed February 2004) All materials for this exercise can be found at: Key words: Group work; hazard prediction; hazard mitigation; role play Contact: Phil Gravestock, Centre for Learning and Teaching,

University of Gloucestershire; 01242 532790; pgravestock@glos.ac.uk