Volcanic geomorphology - an overview

The review examines the role of geomorphology in analyzing the volcanoes on Earth. Five objectives are stressed. First, classifications of volcanic la ndforms should be improved to take care of the complexity in volcanic landf orm generation as magmatic systems, style of eruption, and the erupted mate rial all influence the morphology. Second, geomorphology should contribute to the science of volcanology through its capability in reconstructing grow th 'stages' in complex volcanoes, and also in analyzing the structural fact ors which contribute to the catastrophic collapse of volcanoes. Third, geom orphology can contribute to physical volcanology by assessing the effects o f topography on transport, erosion, and deposition of volcanogenic flows an d identifying the sources and climatic/tectonic conditions which govern the emplacement of volcaniclastic deposits. Fourth, volcanic geomorphology (a) identifies sedimentary facies associations, (b) constructs facies models f or dynamic volcano delivery systems, and (c) analyzes the characteristics o f sediment gravity flows in order to determine relevant parameters for mode lling their behaviour. Fifth, process-oriented geomorphology is critical in developing accurate methods for measuring rates of geomorphic processes th at shape ephemeral volcanic constructs, and for evaluating and comparing ge omorphic impacts on disturbed catchments and the related hydrologic respons e before, during, and after eruptions. This should help to refine parameter s for the exponential decay model. Finally, volcanic geomorphology is essen tial for risk assessment through geomorphic hazard zonation and composite r isk zonation. Such treatments are necessary in order to face the enhanced c hallenge posed by the combination of natural hazards and the increasing num ber of people who are at risk around volcanoes. (C) 1999 Elsevier Science B .V. All rights reserved.