A new reconstructing method of Tsunami attack during the last several thousand years by Sr ratio measurements in a varve of a brackish lake

本研究以青森县小川原湖中部每年一次的层状沉积物岩芯为研究对象，探讨了利用Sr同位素数据重建几千年来海啸袭击历史的可能性。Sr同位素可作为环境沃茨古盐度的代用指标。对小川原湖而言，由于沉积物中Sr同位素的变化不能反映古盐度的变化，因此该方法存在问题。这是由于流入湖泊的河流中Sr浓度较低。

This research is to pursue the possibility in reconstructing the history of tsunami attack during the last several thousand years based on Sr isotopic data extracted from an annually laminated sediment core taken in center part of Lake Ogawara in Aomori Prefecture. The Sr isotope could be served as proxy of paleosalinity of environmental waters. As for the Lake Ogawara, the method is problematic because the variations of Sr isotope in the sediment little reflect the past paleosalinity fluctuation inthe bottom water. This is due to the low Sr concentration in the river flowing to the lake.