Modelling the impact of a hypothetical sub-Plinian eruption at La Soufrière of Guadeloupe (Lesser Antilles)

Abstract This paper describes the development and application of an impact model for a future hypothetical sub-Plinian eruption of La Soufriere of Guadeloupe. The model was designed to assess the impact from either a single or multiple eruption scenarios, each defined in terms of a map of the intensity of three volcanic hazards; volcanogenic earthquake, tephra fallout and pyroclastic density currents. The impact from the three hazards can be assessed independently or alternatively the joint impact of the three hazards can be assessed. The outputs that are produced from the model are; the number of buildings with collapsed roofs, and the number of fatal and non-fatal casualties. Two versions of the impact model were developed, one that uses a spreadsheet and another that is implemented using a Geographical Information System (GIS). Both versions use the same types of hazard inputs and vulnerability functions to derive the number of building collapses and casualties, but have different spatial resolution of the final outputs. The spreadsheet version aggregates the results at a zone level defined specifically for this project whereas the GIS was designed to produce results using 250 m grid-squares. The outputs from the two versions, when using the same eruption scenario, produced somewhat different results, highlighting the importance of defining the appropriate spatial resolution. The vulnerability functions were developed using data on the building stock that was collected by a local survey, in which data on the form of construction, condition, location and types of openings and the variation of these parameters across the affected area were collected. The vulnerability functions incorporated new assessments of fire risks induced by pyroclastic density currents. The model was applied to La Soufriere using a range of input hazard scenarios based on reconstruction of the most recent sub-Plinian magmatic eruption which occurred in 1530 AD. A sensitivity analysis of the model was carried out choosing the inputs from a range of defined input values. The effect on losses and casualties of a range of possible mitigation measures was assessed by running the original model and the modified model using the same input eruption scenario. A separate casualty treatment model was also developed and tested.

[1]  Domenico Ianniello,et al.  Interaction of pyroclastic flows with building structures in an urban settlement: a fluid-dynamic simulation impact model , 2004 .

[2]  Robin Spence,et al.  Residential building and occupant vulnerability to pyroclastic density currents in explosive eruptions , 2007 .

[3]  Robin Spence,et al.  Resistance of Buildings to Pyroclastic Flows: Analytical and Experimental Studies and Their Application to Vesuvius , 2004 .

[4]  R. Spence,et al.  Impact of explosive eruption scenarios at Vesuvius , 2008 .

[5]  Carlo Cavazzoni,et al.  Transient 3D numerical simulations of column collapse and pyroclastic density current scenarios at Vesuvius , 2008 .

[6]  Robin Spence,et al.  Modelling expected physical impacts and human casualties from explosive volcanic eruptions , 2005 .

[7]  Paul D. Cole,et al.  A GIS-based methodology for hazard mapping of small volume pyroclastic density currents , 2007 .

[8]  G. Macedonio,et al.  A model for the numerical simulation of tephra fall deposits , 2005 .

[9]  A. Neri,et al.  4D simulation of explosive eruption dynamics at Vesuvius , 2007 .

[10]  B. Voight,et al.  Pyroclastic flows and surges generated by the 25 June 1997 dome collapse, Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[11]  C. S. Oliveira,et al.  Casualty treatment after earthquake disasters: development of a regional simulation model. , 2000, Disasters.

[12]  Antonella Longo,et al.  A computer model for volcanic ash fallout and assessment of subsequent hazard , 2005, Comput. Geosci..

[13]  B. Voight,et al.  Mechanisms of lava dome instability and generation of rockfalls and pyroclastic flows at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[14]  A. Neri,et al.  The impacts of pyroclastic surges on buildings at the eruption of the Soufrière Hills volcano, Montserrat , 2005 .

[15]  Peter J. Baxter,et al.  Medical effects of volcanic eruptions , 1990 .

[16]  J. Pozzi,et al.  The 1975–1977 crisis of la Soufriere de Guadeloupe (F.W.I): A still-born magmatic eruption , 1983 .

[17]  V. Zobin,et al.  Seismic hazard of volcanic activity , 2001 .

[18]  J. Komorowski,et al.  Reconstruction and analysis of sub-plinian tephra dispersal during the 1530 A.D. Soufrière (Guadeloupe) eruption: Implications for scenario definition and hazards assessment , 2008 .

[19]  R. Sparks,et al.  Deposits from dome-collapse and fountain-collapse pyroclastic flows at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[20]  I. Kelman,et al.  Residential building and occupant vulnerability to tephra fall , 2005 .

[21]  J. Komorowski,et al.  A new scenario for the last magmatic eruption of La Soufrière of Guadeloupe (Lesser Antilles) in 1530 A.D. Evidence from stratigraphy radiocarbon dating and magmatic evolution of erupted products , 2008 .

[22]  G. Natale,et al.  Numerical simulation of pyroclastic density currents on Campi Flegrei topography: a tool for statistical hazard estimation. , 2004 .