Study on disaster protection function of coral reefs and maintenance of structure for reef-island system in atoll nations

这项研究旨在观察环礁国家可持续发展的前景。在印度洋沿着马尔代夫的环礁岛进行了海啸应对措施、底层地质和地形调查，同时在太平洋环礁国家（马歇尔群岛共和国、基里巴斯和图瓦卢）进行了地形调查。我们观察到环礁和珊瑚岛的结构强度与岛屿上基础设施对海啸的脆弱性形成对比。我们还观察到马尔代夫共和国首都马累的一面礁墙在水下发生大规模坍塌。我们的研究结果指出，硬地质结构的全新世珊瑚礁与海底胶结环礁岛屿的基底地质的重要性，也是地质灾害的风险，可能是常见的严重人口过剩的珊瑚礁城市在世界各地。

This study aims to observe prospects for sustainable development of atoll nations. Surveys were conducted for atoll islands on the response against tsunami, substrate geology and topography in Maldives in the Indian Ocean along with the topographic surveys in atoll nations in the Pacific (Republic of Marshall Islands, Kiribati and Tuvalu). We observed the structural strength of atoll and coral islands in contrast to the vulnerability of infrastructures on islands against tsunami. We also observed a large-scale underwater collapse of a reef wall at Male, the capital city of the Republic of Maldives. Our findings point out the importance of hard geological structure of Holocene reef with submarine cementation for substrate geology for atoll islands, and also a geohazard risk that may be common in seriously overpopulated coral cay cities around the world.