Synthesized investigation of seismotectonic vertical processes in the forearc coastal area of the plate convergence zone

板块辐合带弧前沿岸地区地震构造垂直过程综合研究

• 批准号: 16300293
• 负责人: MIYAUCHI Takahiro
• 金额: $ 9.73万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16300293/
• 关键词: plate convergence; non-seismic subsidence; coseismic uplift; Sanriku Coast; core-boring; radiocarbon dating; Holocene; unusual large earthquake; 機械ボーリング; 広域テフラ; 巨大地震履歴; 簡易掘削

We investigated the dynamic combination model of seismotecotonic uplift and non-seismotectonic subsidence, in order to understand tectonic processes originated from the plate convergence between the Pacific Plate and the Eurasia Plate, using Quaternary and geomorphological techniques. The obtained results are as follows.1. A succession of nine marine terraces is recognized, which were formed at interglacial stages at least after MIS21 (ca.800ka). Average uplift rate is estimated to be 0.2 to 0.4m/ka.2. At least Holocene marine terrace is recognizable at the height in 3 to 5 meters along the 120km long, northern coast of the Sanriku Coast. The emergence age is probably between 7ka and 5ka.3. Boring core data of 13 short drilling and 2 long drilling show the tectonic history : successive subsidence in rate of 7-9mm/yr between 8ka and 7ka, a possible episodic uplift producing the emergence of shallow marine topography around 2.9ka, and continuous subsidence with the rate of more than 1mm/yr after 2.9ka.4. Tidal records in the past 50 years at the five ports indicate that the Sanriku Coast is continuously subsiding. The subsidence rate ranges in 2 to 11mm/yr and tend to increase at the port closer to the Japan Trench.5. At least two co-seismic uplift events are practically estimated in the late Holocene, which likely occurred at 7-5ka and 3ka. This seismic scenario prevides that the recurrence time is about 3000 years and the uplift exceeds 10 meters.6. The extreme coseismic event of large uplift along the more than 100km long coast requires the extensive interplate faulting or the branching faulting from the plate boundary for the stress release by plate convergence. Such catastrophic faulting is probably associated with the M8-class earthquakes.

我们利用第四纪和地貌学技术，研究了地震构造隆起和非地震构造沉降的动力组合模型，以了解太平洋板块和欧亚板块之间的板块汇聚所产生的构造过程。所得结果如下： 1．已发现连续九个海洋阶地，它们至少在 MIS21（约 800ka）之后于间冰期形成。平均抬升率估计为0.2至0.4m/ka.2。沿着三陆海岸120公里长的北海岸，至少在3至5米的高度可以辨认出全新世海洋阶地。出苗年龄大概在7ka到5ka.3之间。 13个短钻和2个长钻的钻孔岩心数据显示了构造历史：在8ka和7ka之间以7-9毫米/年的速度连续沉降，在2.9ka左右可能出现间歇性隆起，产生浅海地形，并在2.9ka左右持续沉降。 2.9ka.4之后的速度超过1毫米/年。过去50年五个港口的潮汐记录表明，三陆海岸正在持续下沉。沉降率范围为每年 2 至 11 毫米，并且在靠近日本海沟的港口往往会增加。5。据实际估计，在全新世晚期至少发生了两次同震隆起事件，可能发生在7-5ka和3ka。该地震情景假定复发时间约为3000年，隆升超过10米。6． 100多公里长的海岸大隆起的极端同震事件需要广泛的板间断裂或从板块边界开始的分支断裂，以通过板块汇聚来释放应力。这种灾难性断层活动可能与 M8 级地震有关。

项目成果

日本の地形3 東北

日本地形 3 东北

• 发表时间: 2005
• 作者: Suzuki;T.;小池一之
• 通讯作者: 小池一之

Earthquake Source Fault Beneath Tokyo

• DOI: 10.1126/science.1110489
• 发表时间: 2005-07
• 期刊: Science
• 影响因子: 56.9
• 作者: Hiroshi P. Sato;N. Hirata;K. Koketsu;D. Okaya;S. Abe;R. Kobayashi;M. Matsubara;T. Iwasaki;T. Ito;T. Ikawa;T. Kawanaka;K. Kasahara;S. Harder

日本の地形6 近畿・中国・四国

日本地形 6 近畿、中国、四国

• 发表时间: 2004
• 作者: Naruse;T.;成瀬 敏郎;太田陽子ほか(編)
• 通讯作者: 太田陽子ほか(編)

長井盆地西縁断層帯の第四紀後期活動性と地形発達

长井盆地西缘断裂带晚第四纪活动与地形发育

• 发表时间: 2004
• 期刊: 活断層研究 24
• 作者: 宮内崇裕;平柳幸彦;今泉俊文
• 通讯作者: 今泉俊文