SEISMOTECTONICS OF THE HIDA REGION, CENTRAL HONSHU, JAPAN
SEISMOTECTONICS OF THE HIDA REGION, CENTRAL HONSHU, JAPAN
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DOI：
10.1016/0040-1951(88)90150-3
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发表时间：
1988-03-15
期刊：
影响因子：
2.9
通讯作者：
KOIZUMI, M
中科院分区：
文献类型：
--
作者：
MIKUMO, T;WADA, H;KOIZUMI, M
本文主要根据近6年来对日本本州中部北方希达地区地震活动和震源机制的观测资料，结合地质构造背景和以往大地震的证据，对该地区的地震构造特征进行了较详细的研究。结果表明，该地区的强震活动集中，线理明显，但在中部，沿着Atotsugawa断层延伸约70 km，活动性相对较低。这是该区第四纪主要断裂之一。空间上不均匀分布的高地震活动性可能与1858年希达7.0级地震后的震后应力集中和断层强度不均匀有关。在日本列岛最高的山脉希达山脉下，地震活动也呈带状延伸，地震活动的深度分布明显地集中在Atotsugawa断层下15 km和希达山脉下8 km处。这种局部变化可以解释为脆-韧性转换深度的差异，这表明山下温度较高，涉及活火山。震源机制解表明，最大压应力方向为ESE-WNW方向，这更符合太平洋板块相对于欧亚板块的运动方向，而不是建议的相对运动方向。北美和欧亚板块。在该区域工作的剪切应力的大小估计小于700巴。
Seismotectonic features of the northern Hida region, central Honshu, Japan have been investigated in some detail, mainly on the basis of the last 6 years of observations of seismicity and focal mechanism of a large number of earthquakes, with reference to the geological and tectonic setting and evidence of a large earthquake in the past.It was found that high seismicity is concentrated with a remarkably clear lineation, but with a relatively low activity in the central section, along the Atotsugawa fault extending for about 70 km. This is one of major Quaternary faults in this region. The high seismicity with spatially nonuniform distribution may be related to postseismic stress concentration after the 1858 Hida earthquake (M= 7.0), and to heterogeneous fault strength. Seismicity is also high with belt-like extension beneath the Hida mountain range which is the highest mountain system in the Japan Islands.The depth distribution of seismicity is clearly bounded at 15 km below the Atotsugawa fault and 8 km beneath the Hida mountains. The local variations can be interpreted as being due to the difference in the brittle-ductile transition depth which suggests higher temperature beneath the mountains, involving active volcanoes.The focal mechanism solutions indicate that the maximum compressive stress is oriented in an ESE-WNW direction, which is more consistent with the direction of motion of the Pacific plate relative to the Eurasian plate rather than the suggested relative motion between the North America and Eurasian plates. The magnitude of the shear stress working in this region is estimated to be less than 700 bar.