Palaeo-tsunami inundation distances deduced from roundness of gravel particles in tsunami deposits
Palaeo-tsunami inundation distances deduced from roundness of gravel particles in tsunami deposits
复制标题
根据海啸沉积物中砾石颗粒的圆度推算古海啸淹没距离
DOI：
10.1038/s41598-019-46584-z
复制
发表时间：
2019
影响因子：
4.6
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Ishimura;D.;Yamada;K.
有关古海啸震级的信息对于减轻海啸风险具有科学和社会意义。然而，从沉积物中估计古海啸参数（例如淹没距离）并不简单，因为海啸沉积物反映了复杂的传输过程。在这里，我们展示了一种根据海啸沉积物中多个来源的砾石的混合比例来估计海啸淹没距离的新方法。我们通过图像分析测量了现代海滩和日本沿海山谷河流沉积物中源砾石的圆度，然后计算了海啸沉积物中两种沉积物类型的混合比。通过淹没距离对混合比进行归一化显示，无论海啸强度如何，混合比在恒定百分位处会发生突然变化。这种关系可以估计过去 4000 年来古海啸的淹没距离。
Information on palaeo-tsunami magnitude is scientifically and socially essential to mitigate tsunami risk. However, estimating palaeo-tsunami parameters (e.g., inundation distance) from sediments is not simple because tsunami deposits reflect complex transport processes. Here, we show a new approach to estimate tsunami inundation distance based on the mixture ratio of gravels from several sources in tsunami deposits. We measured the roundness of source gravels in modern beach and fluvial deposits in a coastal valley in Japan through image analysis and then calculated the mixture ratio of both sediment types in tsunami deposits. Normalising the mixture ratios by inundation distances revealed an abrupt change in the mixture ratio at a constant percentile, regardless of tsunami magnitude. This relation allowed estimation of the inundation distance of palaeo-tsunamis during the last 4000 years.