Dendrochronological Research on a Relation Between the Trees from the Botton of the Ashinoko Lake and the Great

我们在1997年和1998年从Ashinoko湖采集了17个样本。由于它们失去了枝叶，我们无法测量树木死亡的准确日期。年表结果分为两组；一个是在公元500年左右。另一个是公元1000年。根据这些消失的边材的年轮估算，前一组的年轮大约是公元600年。后者大约发生在公元1100年。根据古老的记载，大地震发生在公元599年和公元1096年。我们得出的结论是，由于地震，生长在陡坡上的大树被山体滑坡移到了湖底。然后这些树就沉入了湖底。他们看起来就像从湖上的小船上倒过来的。根据这些研究，我们认为袭击该地区的大地震大约有500年的周期。而使用14c（约公元350年）年表的结果。大约在公元900年)比使用树木年代学早了200年。我们可以用14C交叉检查年表的可靠性。我们相信这项研究对于预测该地区未来的地震一定是非常有用的时间信息。目前，我们正在对长尾Chamaecyparis obtusa Endl的年轮进行分析。埋在神山山的泥里…当这个分析完成后，我们就可以明确蛇之子湖的诞生日期。

We took 17 samples from the Ashinoko Lake in 1997,1998. As they lost their sapwoods, we couldn't measure their accurate dates of the death of the trees. The result of the chronology consisted of 2 groups; one was about 500 AD., the other was 1000 AD. Estimating the tree rings of the lost sapwoods, the seasoned date of the former group was about 600 AD., the latter one was in about 1100 AD.. According to the old records, the great earthquakes occurred in 599 and 1096. We had a conclusion that the big trees grown on the steep slope were moved into the bottom of the Lake by landslide because of the earthquakes. Then such trees were sank into the bottom of the Lake. they look like inverted from the boat on the lake.Based on these researches , we think that the great earthquakes attacked this area had a cycle of about 500 years. And the result of the chronology using 14 C (about 350AD., and 900 AD.) was about 200 years earlier than using dendrochronology. We can crosscheck the reliability of the chronology using 14C. We believe that this research must be very helpful chronological information for predicting a future earthquake in this area.Now we are being involved in analyzing the tree rings of Chamaecyparis obtusa Endl. buried in the mud of Kamiyama Mt.. When this analysis is completed, we can clear the birth date of the Ashinoko Lake.