Carmen Solana

Framing volcanic risk communication within disaster risk reduction: finding ways for the social and physical sciences to work together

Abstract Sixteen years have passed since the last global volcanic event and more than 25 since a volcanic catastrophe that killed tens of thousands. In this time, volcanology has seen major advances in understanding, modelling and predicting volcanic hazards and, recently, an interest in techniques for reducing and mitigating volcanic risk. This paper provides a synthesis of literature relating to this last aspect, specifically the communication of volcanic risk, with a view to highlighting areas of future research into encouraging risk-reducing behaviour. Evidence suggests that the current ‘multidisciplinary’ approach within physical science needs a broader scope to include sociological knowledge and techniques. Key areas where this approach might be applied are: (1) the understanding of the incentives that make governments and communities act to reduce volcanic risk; (2) improving the communication of volcanic uncertainties in volcanic emergency management and long-term planning and development. To be successful, volcanic risk reduction programmes will need to be placed within the context of other other risk-related phenomena (e.g. other natural hazards, climate change) and aim to develop an all-risks reduction culture. We suggest that the greatest potential for achieving these two aims comes from deliberative inclusive processes and geographic information systems.

Large Coastal Landslides and Tsunami Hazard in the Caribbean

With nine volcanic peaks in a 750-square-kilometer area, Dominica, in the Lesser Antilles volcanic arc (Figure 1), has one of the highest concentrations of potentially active volcanoes in the world [Lindsay et al., 2005]. Dominica is very hilly, and there have been numerous landslides, particularly on the islands wetter eastern and northern coasts. Lindsay et al. [2005] consider the likelihood of gravitational collapses on the flanks of Dominicas volcanoes to be “low but not negligible.” However, many factors make Dominica particularly prone to large landslides (>1 million tons): (1) extensive zones of weakened rock, due to hydrothermal alteration and/or intense tropical weathering; (2) oversteepened slopes associated with tectonic uplift and erosion of volcanic edifice foot slopes; (3) large amounts of rainfall on the volcanic uplands, especially during the hurricane season (June–October), with annual averages of up to approximately 6000 millimeters; and (4) occasional severe seismic activity, e.g., a magnitude 7.3 earthquake on 29 November 2007, with its epicenter between Dominica and Martinique, and another of magnitude 6.2 on 21 November 2004, with its epicenter between Dominica and Guadeloupe.

Impact of Environmental Factors on the Spectral Characteristics of Lava Surfaces: Field Spectrometry of Basaltic Lava Flows on Tenerife, Canary Islands, Spain

We report on spectral reflectance measurements of basaltic lava flows on Tenerife Island, Spain. Lava flow surfaces of different ages, surface roughness and elevations were systematically measured using a field spectroradiometer operating in the range of 350–2500 nm. Surface roughness, oxidation and lichen coverage were documented at each measured site. Spectral properties vary with age and morphology of lava. Pre-historical lavas with no biological coverage show a prominent increase in spectral reflectance in the 400–760 nm range and a decrease in the 2140–2210 nm range. Pāhoehoe surfaces have higher reflectance values than ʻaʻā ones and attain a maximum reflectance at wavelengths < 760 nm. Lichen-covered lavas are characterized by multiple lichen-related absorption and reflection features. We demonstrate that oxidation and lichen growth are two major factors controlling spectra of Tenerife lava surfaces and, therefore, propose an oxidation index and a lichen index to quantify surface alterations of lava flows: (1) the oxidation index is based on the increase of the slope of the spectral profile from blue to red as the field-observed oxidation level strengthens; and (2) the lichen index is based on the spectral reflectance in the 1660–1725 nm range, which proves to be highly correlated with lichen coverage documented in the field. The two spectral indices are applied to Landsat ETM+ and Hyperion imagery of the study area for mapping oxidation and lichen coverage on lava surfaces, respectively. Hyperion is shown to be capable of discriminating different volcanic surfaces, i.e., tephra vs. lava and oxidized lava vs. lichen-covered lava. Our study highlights the value of field spectroscopic measurements to aid interpretation of lava flow characterization using satellite images and of the effects of environmental factors on lava surface evolution over time, and, therefore, has the potential to contribute to the mapping as well as dating of lava surfaces.

Dating Lava Flows of Tropical Volcanoes by Means of Spatial Modeling of Vegetation Recovery

The age of past lava flows is crucial information for evaluating the hazards and risks posed by effusive volcanoes, but traditional dating methods are expensive and time-consuming. This study proposes an alternative statistical dating method based on remote sensing observations of tropical volcanoes by exploiting the relationship between lava flow age and vegetation cover. First, the factors controlling vegetation density on lava flows, as represented by the normalized difference vegetation index (NDVI), were investigated. These factors were then integrated in pixel-based multi-variable regression models of lava flow age to derive lava flow age maps. The method was tested at a pixel scale on three tropical African volcanoes with considerable recent effusive activity: Nyamuragira (Democratic Republic of Congo), Mt Cameroon (Cameroon) and Karthala (the Comoros). Due to different climatic and topographic conditions, the parameters of the spatial modeling are volcano-specific. Validation suggests that the obtained statistical models are robust and can thus be applied for estimating the age of unmodified undated lava flow surfaces for these volcanoes. When the models are applied to fully vegetated lava flows, the results should be interpreted with caution due to the saturation of NDVI. In order to improve the accuracy of the models, when available, spatial data on temperature and precipitation should be included to directly represent climatic variation.

Translations of volcanological terms: cross-cultural standards for teaching, communication, and reporting

When teaching at a non-English language university, we often argue that because English is the international language, students need to become familiar with English terms, even if the bulk of the class is in the native language. However, to make the meaning of the terms clear, a translation into the native language is always useful. Correct translation of terminology is even more crucial for emergency managers and decision makers who can be confronted with a confusing and inconsistently applied mix of terminology. Thus, it is imperative to have a translation that appropriately converts the meaning of a term, while being grammatically and lexicologically correct, before the need for use. If terms are not consistently defined across all languages following industry standards and norms, what one person believes to be a dog, to another is a cat. However, definitions and translations of English scientific and technical terms are not always available, and language is constantly evolving. We live and work in an international world where English is the common language of multi-cultural exchange. As a result, while finding the correct translation can be difficult because we are too used to the English language terms, translated equivalents that are available may not have been through the peer review process. We have explored this issue by discussing grammatically and lexicologically correct French, German, Icelandic, Indonesian, Italian, Portuguese, Russian, Spanish, and Japanese versions for terms involved in communicating effusive eruption intensity.

Communication between professionals during volcanic emergencies

Successful communication between scientists, officials, media, and the public is imperative during a volcanic crisis. Misunderstanding can lead to confusion and distrust, and it ultimately can transform an emergency into a disaster. Experience developed during volcanic crises in the Caribbean has helped identify ‘good practice’ guidelines for communication by scientists during volcanic emergencies (see “Communication during volcanic emergencies: An operations manual for the Caribbean, by C. Solana et al., Benfield Greig Haz.Res. Cent., Univ. Coll. London, 2001; available at http://www.bghrc.com).