Late Pleistocene-Holocene activity and paleoseismicity of the Nojima Fault in the northern Awaji Island, southwest Japan.
Late Pleistocene-Holocene activity and paleoseismicity of the Nojima Fault in the northern Awaji Island, southwest Japan.
复制标题
日本西南部淡路岛北部野岛断层的晚更新世-全新世活动和古地震活动。
DOI：
10.1016/j.tecto.2018.10.009
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
Aiming Lin
中科院分区：
文献类型：
--
作者：
Aiming Lin and Takafumi Nishiwaki;Peng Chen and Aiming Lin* (*corresponding author);Peng Chen and Aiming Lin* (*corresponding author);Aiming Lin,Peng Chen,Koichiro Sado;Aiming Lin
野外调查和构造地貌分析表明，晚更新世-全新世形成的阶地升降和冲积扇的地形标志沿1995年神户6.9级地震发生的野岛断裂系统地错动了约40-62 m。构造地貌分析、海沟挖掘和放射性碳测年结果表明，1995年神户6.9级地震前的至少两次大地震发生在约1800 年，最近一次地震发生在约1000 CE，倒数第二次大地震发生在约200 CE，表明野岛断裂大地震的平均复发间隔约为900 年。根据构造地貌的变形特征和放射性碳测年结果，估计野岛断裂晚更新世-全新世走滑右行速率为~2.0~3.0 mm/a，平均为2.5 mm/a。这些发现表明，以前的研究大大高估了野岛断层的复发间隔，低估了其滑动速率。因此，野岛断层造成的地震危险比之前认为的要大得多，因此，有必要重新评估日本西南部人口稠密的Awaji-Kobe地区的潜在地震危险。
Field investigations and analyses of tectonic landforms show that the topographical markers of terrace risers and alluvial fans formed in the late Pleistocene-Holocene have been systematically offset by ~40–62 m along the Nojima Fault on which the 1995 Mw6.9 Kobe earthquake occurred. Analysis of tectonic landforms, trench excavations, and radiocarbon dating results reveal that i) at least two large earthquakes prior to the 1995 Mw6.9 Kobe earthquake occurred in the past ~1800 years; ii) the most recent event occurred in ~1000 CE, and the penultimate large earthquake event took place in ~200 CE, suggesting an average recurrence interval of ~900 yr for large earthquakes on the Nojima Fault. Based on the deformation features of tectonic landforms and radiocarbon dating ages, the late Pleistocene-Holocene strike-slip right-lateral rate is estimated to be ~2.0–3.0 mm/yr with an average of 2.5 mm/yr for the Nojima Fault. These findings show that previous studies had significantly overestimated the recurrence interval and underestimated the slip rate of the Nojima Fault. Accordingly, the Nojima Fault poses a much greater seismic hazard than previously believed, and therefore, it is necessary to reassess the potential seismic hazard for the densely-populated Awaji-Kobe regions, southwest Japan.