Geohazards and myths: ancient memories of rapid coastal change in the Asia-Pacific region and their value to future adaptation

Patrick D Nunn

doi:10.1186/2196-4092-1-3

Abstract

Rapid coastal change is common in the Asia-Pacific region yet an understanding of its causes, recurrence times, and impacts is not always clear through the use of conventional geological methods. It is suggested that myths (traditional [oral] tales) are underutilized sources of information about coastal change in this region. This is illustrated by consideration of myths likely to recall (early) Holocene sea-level rise, particularly along the coasts of India and Australia, as well as myths recalling rapid episodic coastal emergence and submergence, the latter including the disappearance of entire landmasses (islands). Two examples of how details in such myths can inform geological understanding of coastal change are given. The first argues that myths recalling the rapid flooding of coastal cities/lowlands are likely to represent memories of extreme wave events superimposed on a rising (postglacial) sea level. The second suggests that many myths about landmass/island disappearance fail to report the occurrence of rapid (coseismic and aseismic) subsidence even though they provide inferential evidence that this occurred. Few such myths are known to the author from many parts of Asia yet it is likely they exist and could, as elsewhere in the world, help illuminate the understanding of the nature and chronology of rapid coastal change. The challenges involved in helping communities in the Asia-Pacific region adapt to future coastal changes might be partly overcome by the use of appropriate myths to demonstrate precedents and engender local participation in adaptation strategies.

Highlights

Coasts in the Asia-Pacific region are sometimes subject to rapid change
The largely unacknowledged source of data about rapid coastline change in the Asia-Pacific region on which this paper focuses is myth, the traditional tales that are characteristic of many of the unique cultures in this region [6,7,8,9]
Given that people have been living on Pacific islands for only the past 3000 years or so [35], slightly after the time of the Holocene sea-level maximum in this region [36], it is no surprise that, despite the formidable body of oral traditions that exist there [6,37], there are none that plausibly recall slow, enduring sea-level rise as there are in India and Australia

Summary

Introduction

Coasts in the Asia-Pacific region are sometimes subject to rapid change. Conventional geoscientific methods have commonly been used to understand the causes and recurrence intervals of rapid coastal change but these methods have not always proved adequate to identify incidences of occasional (low-frequency) rapid (often high-magnitude) change because the evidence for these is obscured by later coastal changes, and understand how rapid coastal changes impacted coastal societies and ecosystems at particular times.The most common types of rapid change are those associated with the impact of large waves, be they storm surges or tsunamis, that may alter both the position and nature of the shoreline. For all these types of rapid coastal change, there is interest in knowing how often (frequency) and how much (magnitude) they affect particular Asia-Pacific coasts, not least to understand the effects they might have should they re-occur in the future [5].

Results

Conclusion