Tropical cyclones - Extreme Events: A Physical Reconstruction and Risk Assessment - page 108

Conclusion
Palaeotempestology, the study of prehistoric storms, offers much greater
insight into the nature of storms likely to impact a region than short histori-
cal records alone. Patterns and periodicities of prehistoric storms can be recon-
structed from sediments, both organic and lithic, deposited by surge and waves
at elevations or distances inland beyond the reach of normal marine processes.
Erosional terraces can also be left in the landscape by the same processes. Tech-
niques such as isotopic variations in speleothems, tree rings and variations in
pollen species within sediments also hold promise as tools in deciphering long-
term records of prehistoric tropical cyclones.
Millennial and century scale periodicities have been identified from sedi-
mentary records in the south and southeastern USA and northern Australia,
respectively, and such patterns highlight regime changes in the magnitude--
frequency relationship of tropical cyclones over time in these regions. Recogni-
tion of these regime changes can really only be achieved through the use of the
prehistoric record of these events where historical records are relatively short.
Identifying the length of regimes, and mechanisms causing regime shifts, will
become increasingly important for making more accurate predictions of the lev-
els of risk and exposure as human populations, urbanisation and tourism grow
rapidly along tropical and subtropical coasts.