Catastrophic events

Project leader: Adam Switzer

 

Aim

To better understanding of the dynamics, recurrence intervals of and recovery from catastrophic coastal events including storm surges, rapid subsidence/uplift and tsunami in order to promote sustainable coastal development and enhance the socio-economic development of coastal communities.

 

Background

Recent catastrophic events including Typhoon Morakot, Hurricane Katrina, Cyclone Nargis, the 2004 Indian Ocean Tsunami and the 2011 Tohoku-Oki Tsunami have raised global awareness of the risk posed to coastal communities by tropical storms, coastal tectonics and tsunamis. The 2004 Indian Ocean Tsunami provided new insight into the geological deposits and geomorphological impacts of a large tsunami and now leaves the research community with a new challenge of re-examining how we investigate events from the past. The 2004 tsunami and recent storm events have also provided a unique opportunity to further develop criteria to distinguish palaeotsunami deposits from those deposited by storms or other extreme events e.g. 1,2,3,4.

Others have continued the search for palaeotsunami including important research in Thailand e.g. 5,6, Indonesia 7 and Sri Lanka8, which provided geological indicators of prehistoric precursors to the 2004 event. Globally palaeotsunami work has furthered the use of coastal stratigraphy to study the recurrence interval of catastrophic tsunami events e.g. 4,9,10,11 although considerable palaeotsunami work is still required particularly in the many developing nations at significant risk (Myanmar, Vietnam, China).

The debate over the effect of global warming on the frequency and/or intensity of tropical cyclones during the past few decades and the century ahead is ongoing and will form a major focus of this research theme. The instrumental record of storm activity is too short to produce reliable predictions of catastrophic environmental changes. Therefore, obtaining a record of present and past landfalling storms, and their extent of geological and ecological impacts, is one of few means to assess future risk, reveal the spatial and temporal variability of storm activity and decipher its relationship with global climatic changes. New techniques are emerging that now enable identification of past tropical cyclones and storms and which significantly improve our knowledge of the field of palaeotempestology e.g.12,13,14.

Another ongoing debate that will form a major focus of this research theme is the study of boulder deposits and megaclasts on rocky shorelines and tropical reefs and their implications for hazard assessment and palaeoevent investigation15,16. Recent works have indicated the equivocal nature of many boulder features 16,17 indicating that this field of research will be one of continued debate over the period of the project.

The catastrophic events research theme will draw together scientists working on storms and tsunamis for interdisciplinary meetings involving, geologists, geomorphologists, hydrodynamicists, engineers and social scientists with the aim of assisting coastal communities to develop an understanding of risk and plan for sustainable coastal development. A major focus of this theme will be assisting developing nations to mitigate for coastal hazards.

 

Research questions

  • How do different coastal settings and environments react to and recover from catastrophic events associated with large storms and tsunami?

  • How can new technologies and an improved understanding of storm and tsunami inundation assist in reducing risk to coastal communities?

  • By what mechanisms can palaeo-event studies best be incorporated into coastal planning and risk management?

  • How can an improved the understanding developed from recent catastrophic events be used to guide coastal planning in developing nations?

 

 

 

References

1 Dawson, A.F. and Stewart, I. 2007. Tsunami deposits in the geological record. Sedimentary Geology 200:166-183.

2 Morton R.A., et al. 2007.   Physical criteria for distinguishing sandy tsunami and storm deposits using modern examples. Sedimentary Geology 200(3-4): 184-207.

3 Kelletat, D. 2008. Comments to Dawson, AG and Stewart, I., 2007., Tsunami deposits in the geological record. - Sedimentary Geology 200, 166-183 Discussion. Sedimentary Geology 211(3-4):87-91.

4 Switzer A.D and Jones B.G. 2008. Large-scale washover sedimentation in a freshwater lagoon from the southeast Australian coast: tsunami or exceptionally large storm. The Holocene 18(5): 787-803.

5 Jankaew, K., et al. 2008. Medieval forewarning of the 2004 Indian Ocean tsunami in Thailand. Nature 455(7217):1228-1231.

6 Sawai, Y., et al. 2009. Diatom assemblages in tsunami deposits associated with the 2004 Indian Ocean tsunami at Phra Thong Island, Thailand. Marine Micropaleontology 73(1-2):70-79.

7 Monecke K., et al. 2008. A 1,000-year sediment record of tsunami recurrence in northern Sumatra. Nature 455(7217):1232-1234.

8 Dahanayake, K. and Kulasena, N., 2008. Recognition of diagnostic criteria for recent- and paleo-tsunami sediments from Sri Lanka. Marine Geology 254(3-4):180-186.

9 McFadgen, B. G. and Goff J. R. 2007. Tsunamis in the New Zealand archaeological record. Sedimentary Geology 200(3-4):263-274.

10 Switzer, A.D., et al. 2005. Sea-level, storms or tsunami; enigmatic sand sheet deposits in sheltered coastal embayment from southeastern New South Wales Australia. Journal of Coastal Research 21(4):655-663.

11 Vott A., et al. 2008. Strong tsunami impact on the Bay of Aghios Nikolaos and its environs (NW Greece) during Classical-Hellenistic times. Quaternary International 181(1):105-122.

12 Donnelly, J.P., and Woodruff, J.D. 2007. Intense hurricane activity over the past 5,000 years controlled by El Nino and the West African monsoon. Nature 447:465-468.

13 Horton, B.P., et al. 2009. Holocene sea-level changes along the North Carolina Coastline and their implications for glacial isostatic adjustment models. Quaternary Science Reviews 28:1725-1736.

14 Mann, D. H., et al. 2008. Post-glacial relative sea level, isostasy, and glacial history in Icy Strait, Southeast Alaska, USA. Quaternary Research 69(2):201-216.

15 Ettiene S. and Paris R. 2010 Boulder accumulations related to storms on the south coast of the Reykjanes Peninsula (Iceland). Geomorphology 114(1-2):55-70.

16 Switzer, A.D. and Burston J.M. 2010 Competing mechanisms for boulder deposition on the southeast Australian coast. Geomorphology 114(1-2): 42-54.

17 Felton, E. A. and Crook K. A. W., 2003. Evaluating the impacts of huge waves on rocky shorelines: an essay review of the book 'Tsunami - The Underrated Hazard’, Marine Geology 197(1-4), 1-12.