Sedimentary differences between the 1993 Hokkaido-nansei-oki tsunami and the 1959 Miyakojima typhoon at Taisei, southwestern Hokkaido, northern Japan
Sedimentary differences between the 1993 Hokkaido-nansei-oki tsunami and the 1959 Miyakojima typhoon at Taisei, southwestern Hokkaido, northern Japan
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DOI：
10.1016/s0037-0738(00)00076-2
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发表时间：
2000-09-01
影响因子：
2.8
通讯作者：
Ishii, M
中科院分区：
文献类型：
--
作者：
Nanayama, F;Shigeno, K;Ishii, M
海啸沉积物与风暴沉积物截然不同，在北海道西南部的大成镇的一个海沟中可以看到，1959年大成镇遭受了台风袭击，1993年又遭受了海啸袭击。台风产生的风暴潮在一个小时内达到了比普通涨潮高6米左右的高峰。海啸是由附近7.8级地震引起的，包含两个主波，比台风风暴潮高1-3米。我们在距离海滩60米的内陆3 × 9米的海沟中发现了台风和海啸留下的沉积物。沉积物的厚度相似，在这两种情况下，沉积物的厚度都从最大约50厘米向陆地减少。海啸沉积物可划分为四层，可能与两个主要海啸波的向陆和向海流动有关；通过砾石织物和倒下的植物的残骸来显示行方向。向陆地方向的海啸沉积了海相砂和圆形砾石，而回流沉积了土壤、非海相砂和带有植物碎片的溪流砾石的混杂物。只有风暴沉积物显示出森林层理。这种沉积物主要是海砂，比任何海啸层都要分类好。(C) 2000 Elsevier Science B.V.版权所有
Tsunami deposits differ distinctly from storm deposits as seen in a trench in the southwestern Hokkaido town of Taisei, which was struck by a typhoon in 1959 and a tsunami in 1993. The typhoon generated a storm surge that crested about 6 m above ordinary high-tide levels for 1 h. The tsunami, caused by a nearby earthquake with a magnitude of 7.8, contained two main waves and was 1-3 m higher than the typhoon surge. We found deposits from both the typhoon and the tsunami in a 3 by 9 m trench located 60 m inland from the beach. The deposits are similar in thickness, which in both cases decrease landward from a maximum of about 50 cm. The tsunami deposits can be divided into four layers probably correlative with landward and seaward flows from the two main tsunami waves; the Row directions are shown by gravel fabrics, and remains of knocked-down plants. The landward tsunami how deposited marine sand and rounded gravel, whereas the return flow deposited a poorly sorted mixture of soil, non-marine sand, and stream gravel with plant fragments. Only the storm deposit shows foreset bedding. This deposit is mostly marine sand that is better sorted than any of the tsunami layers. (C) 2000 Elsevier Science B.V. All rights reserved.