36°34′12″N 140°25′48″E / 36.570°N 140.430°E
The Idosawa Fault (井戸沢断層, Idozawa Dansō)[1] is an active earthquake fault with a length of 8 mi (13 km), located primarily west of Iwaki city in Japan. It mainly consists of a trace of three striations. Although the Idosawa Fault primarily behaves as a normal dip-slip fault, it also consists of a north-trending component described as a left-lateral strike-slip fault.[2] The main structural trend is north-northwest–south-southeast, with sinking observed only to the south on the east side of the fault. Metamorphic rock and Cretaceous strata, as well as granite and epidiorite are distributed in the region; the fault is described as a limit to the distribution of tuff from the Neogene Period.[3]
Notable earthquakes
- March 19, 2011: A magnitude 6.1 struck near Ibaraki Prefecture, with its hypocenter located near the Idosawa Fault. The earthquake occurred as a result of normal-faulting.[4]
- March 23, 2011: A magnitude 6.0 earthquake struck near northern Ibaraki. The quake occurred near the fault, with a focal mechanism of a normal-fault type.[4]
- April 11, 2011: A magnitude 6.6 earthquake with a depth of 6 mi (10 km) struck near Ishikawa, Fukushima. The quake occurred along the fault and caused a surface rupture of near 4 mi (7 mi). In addition, a vertical displacement of 0.8–1.8 m was observed.[3]
See also
References
- ^ "いわき市の地表に７キロの断層 ４月１１日の余震でずれ". asahi.com. Asahi Shimbun Company. 13 April, 2011. Retrieved 2011-04-23.
{{cite web}}: Check date values in:|date=(help) - ^ 恒石, 幸正 (15 August, 2008). "地塊運動の機構に関する地質学的実験的研究". porta.ndl.go.jp. Earthquake Research Institute. Retrieved 2011-04-23.
{{cite web}}: Check date values in:|date=(help) - ^ a b "The surface earthquake fault of the 11th April 2011 earthquake in Hamadoori Fukushima pref". outreach.eri.u-tokyo.ac.jp. Outreach and Public Relations Office. 13 April, 2011. Retrieved 2011-04-23.
{{cite web}}: Check date values in:|date=(help) - ^ a b Active Fault and Earthquake Research Center (2011). "Study on related inland earthquakes". National Institute of Advanced Industrial Science and Technology. Retrieved 2011-04-23.