A revised tsunami source model for the 1707 Hoei earthquake and simulation of tsunami inundation of Ryujin Lake, Kyushu, Japan
A revised tsunami source model for the 1707 Hoei earthquake and simulation of tsunami inundation of Ryujin Lake, Kyushu, Japan
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DOI：
10.1029/2010jb007918
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发表时间：
2011-02-16
影响因子：
3.9
通讯作者：
Maeda, Takuto
中科院分区：
文献类型：
--
作者：
Furumura, Takashi;Imai, Kentaro;Maeda, Takuto
基于许多近期的研究结果，比如来自日本全国性的GEONET全球定位系统网络的大地测量数据，以及对九州被海啸淹没的龙神湖的地质调查，我们提出了一个修正后的1707年宝永地震震源破裂模型。该地震发生在日本西南部外的南海海槽。新的宝永地震震源模型的震源破裂区域延伸得更远，到达日向滩，比目前所公认的位于四国最西端的位置还要远70多公里。使用新的宝永地震震源破裂模型对海啸进行的数值模拟，更一致地解释了从四国西部到九州的太平洋沿岸所观测到的非常高的海啸的分布情况。使用新模型所估算的近岸海啸对海啸涌入龙神湖进行的模拟，展示了一个海啸淹没过程；流入和流出速度影响着湖内以及连接湖与海洋的河道周围沙子的搬运和沉积。684年天武、1361年正庆和1707年宝永地震引发的海啸在龙神湖以及连接湖与海洋的河道周围沉积了沙子，但是其他地震引发的较小海啸无法到达龙神湖。这种不规则的行为表明，除了100 - 150年的常规南海海槽地震周期外，还存在一个300 - 500年的超强地震周期。这些更大的地震在从四国西部到九州的区域产生了最大的海啸。
Based on many recent findings such as those for geodetic data from Japan's GEONET nationwide GPS network and geological investigations of a tsunami-inundated Ryujin Lake in Kyushu, we present a revised source rupture model for the great 1707 Hoei earthquake that occurred in the Nankai Trough off southwestern Japan. The source rupture area of the new Hoei earthquake source model extends further, to the Hyuga-nada, more than 70 km beyond the currently accepted location at the westernmost end of Shikoku. Numerical simulation of the tsunami using a new source rupture model for the Hoei earthquake explains the distribution of the very high tsunami observed along the Pacific coast from western Shikoku to Kyushu more consistently. A simulation of the tsunami runup into Ryujin Lake using the onshore tsunami estimated by the new model demonstrates a tsunami inundation process; inflow and outflow speeds affect transport and deposition of sand in the lake and around the channel connecting it to the sea. Tsunamis from the 684 Tenmu, 1361 Shokei, and 1707 Hoei earthquakes deposited sand in Ryujin Lake and around the channel connecting it to the sea, but lesser tsunamis from other earthquakes were unable to reach Ryujin Lake. This irregular behavior suggests that in addition to the regular Nankai Trough earthquake cycle of 100-150 years, there is a hyperearthquake cycle of 300-500 years. These greater earthquakes produce the largest tsunamis from western Shikoku to Kyushu.