Abstract
This paper discusses the influence of the geological setting of islands and reefs in the Maldives on the impact of the 26 December 2004 Indian Ocean Tsunami. Geological and geomorphological data (including orientation, location, size, ellipticity, reef-island distance, proportion of reef area to island area) were collected for completely flooded and <25% flooded islands. The results show that although the different parameters may interact to reduce or magnify the impact, the reef-island distance is the most important factor. The critical minimum distance between the reef and the island shoreline required for the wave to set up is estimated as 89 m on the eastern and 140 m on the western sides of the island, respectively. Circular islands with short reef-island distance and small percent of reef area seem to be safer in the context of tsunami. The result of this study can be applied to identify islands that are naturally protected/resilient against natural disasters such as tsunami and those where the hazard is greatest.
Résumé
Cet article discute de l’influence du contexte géologique d’îles et de récifs des Maldives sur l’impact du tsunami du 26 décembre 2004 dans l’Océan indien. Les données géologiques et géomorphologiques (comportant la situation, l’orientation, la taille, l’ellipticité, la distance récif-île, la surface de récifs rapportée à la surface de l’île) ont été rassemblées pour les îles complètement inondées et les îles inondées à moins de 25%. Il apparaît que, bien que différents paramètres peuvent interagir pour réduire ou amplifier l’impact, la distance récif-île est le facteur le plus important. La distance minimum critique entre le récif et le rivage de l’île nécessaire pour que la vague se forme est estimée à 89 m pour les côtes est et à 140 m pour les côtes ouest. Les îles circulaires présentant une faible distance récif-île et un faible pourcentage de surface de récif semblent être plus sûres en cas de tsunami. Les résultats de l’étude peuvent être utilisés pour distinguer les îles qui sont naturellement protégées et capables de faire face à des désastres naturels tels que les tsunamis de celles où l’aléa est plus important.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Ali M (2000) Reef island geomorphology: formation development and prospective of islands in Eta atoll, South Maalhosmadulu. Dissertation, 342 pp, University of New South Wales
AusAID (2005) An assessment of damage to Maldivian coral reefs and baitfish populations from the Indian Ocean Tsunami: prepared by an Australian Government Mission and the Maldives Marine Research Centre
Fritz HM et al (2006) Maldives field survey after the December 2004 Indian Ocean Tsunami. Earthq Spectra 22(S3):S137–S154
Fujima K et al (2006) Survey results of the Indian Ocean Tsunami in the Maldives. Coastal Eng J 48:81–97
Gischler E et al (2008) Late Quaternary reef growth and sea level in the Maldives (Indian Ocean). Mar Geol 250:104–113
Gourlay MR (1988) Coral cays: products of wave action and geological processes in a biogenic environment. Proc 6th Int Coral Reef Symp 2:491–496
Grilli ST et al (2006) Source constraints and model simulation of the December 26, 2004 Indian Ocean Tsunami. ASCE J Waterways Port Ocean and Coastal Eng 133(6):414–428
Harangozo SA (1992) Flooding in the Maldives and its implications for the global sea level rise debate. In: Woodworth PL, Pugh DT, DeRonde JG, Hannah J (eds), Sea level change: determination and effects. Geophys Monographs 69:95–99
Kan H et al (2007) The 2004 Indian Ocean Tsunami in the Maldives: scale of the disaster and topographic effects on atoll reefs and islands. Atoll Res Bull No 554:1–65
Keating BH et al (2005) 2004 Indian Ocean Tsunami on the Maldives islands: initial observations. Sci Tsunami Hazards 23(2):19–49
Kench PS, Brander RW (2006) Response of reef island shorelines to seasonal climate oscillations: south Maalhosmadulu atoll, Maldives. J Geophys Res 111:F01001. doi:101029/2005JF000323
Kench PS et al (2006) Geological effects of tsunami on mid-ocean atoll islands: the Maldives before and after the Sumatran tsunami. Geol 34(3):177–180
Kench PS et al (2007) Impact of the Sumatran Tsunami on the geomorphology and sediments of reef islands: South Maalhosmadulu Atoll, Maldives. Atoll Res Bull No 544:105–134
Khan TMA et al (2002) Relative sea level changes in Maldives and vulnerability of land due to abnormal coastal inundation. Mar Geodesy 25:133–143
Massel SR, Gourlay MR (2000) On the modeling of wave breaking and set-up on coral reefs. Coastal Eng 32:1–27
Riyaz M, et al. (2008) Combined effect of island topography and reef morphology in dissipating tsunami wave energy in Maldives. Proceedings of conference on marine problems and specific solutions, COMPASS 2008, June 15–18, Maldives, pp 71–77
Riyaz M, Park KH (2008) Reef slope failure in the northeastern corner of Malé, Maldives. 11th International coral reef symposium, July 7–11, Florida, USA
Riyaz M, Park KH (2009) Safer island concept developed after the 2004 Indian Ocean Tsunami: a case study of Maldives. J Earthq Tsunami, Accepted for publication
Stein S, Okal EA (2005) Size and speed of the Sumatra earthquake. Nature 434:580–582
UNEP (2005) After the tsunami: rapid environmental assessment. United Nations Environment Programme, 141 pp. http://www.unep.org/tsunami/reports/SUNAMI_report_complete.pdf
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Riyaz, M., Park, KH., Ali, M. et al. Influence of geological setting of islands and significance of reefs for tsunami wave impact on the Atoll Islands, Maldives. Bull Eng Geol Environ 69, 443–454 (2010). https://doi.org/10.1007/s10064-010-0278-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10064-010-0278-y