Graduate school of Science, Tohoku University, Aoba 468-1 E303, Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
International Research Institute of Disaster Science, Tohoku University, Aoba 468-1 Aramaki, Aoba-ku, Sendai, 980-0845, Japan.
Sci Rep. 2020 Apr 29;10(1):7218. doi: 10.1038/s41598-020-64100-6.
Typhoons and associated storm waves in the northwestern Pacific Ocean commonly cause coastal disasters. The possibility remains that an even stronger typhoon than the strongest one observed to date might have occurred before. The development of a method to estimate a maximum intensity of past typhoons over thousands of years is important for paleoclimatology, paleoceanography and disaster prevention. Numerous storm wave boulders exist on reefs in the Ryukyu Islands, Japan, which have been deposited to their present position by the cumulative effects of the past storm waves. These boulders can be used as proxies for the hydrodynamic conditions of the largest waves from past events. Here, we present numerical computations for storm waves and boulder transport with the boulder distribution as a constraint factor to estimate the maximum intensities of storm waves and their causative typhoon events over the past 3500 years. Though the intensities of the maximum estimated waves and associated typhoon events were slightly stronger than those recorded over the past ~70 years in the Ryukyu Islands, our results suggest that no abnormally intense typhoon has struck the Ryukyu Islands in the past 3500 years. The potential impact from tsunamis remains uncertain; however, our results are meteorologically reasonable.
西北太平洋的台风和相关风暴波通常会引发沿海灾害。此前可能发生过比迄今观测到的最强台风还要强烈的台风。开发一种方法来估算过去几千年中台风的最大强度对于古气候学、古海洋学和灾害预防都很重要。日本琉球群岛的珊瑚礁上存在大量的风暴波巨石，这些巨石是过去风暴波的累积效应将它们带到现在的位置上的。这些巨石可以作为过去最大海浪水动力条件的代用指标。在这里，我们提出了风暴波和巨石输运的数值计算，将巨石分布作为约束因子，以估算过去 3500 年中风暴波的最大强度及其引发的台风事件。尽管最大估计波的强度和相关台风事件的强度略高于过去 70 年在琉球群岛记录的强度，但我们的结果表明，在过去 3500 年中，没有异常强烈的台风袭击过琉球群岛。海啸的潜在影响仍不确定；然而，我们的结果在气象学上是合理的。
