Aomori Bay West Coast Fault Zone Explained

Aomori Bay West Coast Fault Zone
Other Name:青森湾西岸断層帯
Aomoriwan-seigan Dansō-tai
Pushpin Map:Japan Tohoku
Pushpin Map Caption:Location in Tohoku
Pushpin Relief:1
Country:Japan
Region:Tōhoku
Cities:Aomori, Yomogita
Segments:Aomori Bay West Fault, Nogiwa Fault, Nyunai Fault
Length:31km (19miles)
Displacement:0.4-/1000 years
Plate:Okhotsk (maybe North America)
Status:Active
Type:reverse fault
Age:Miocene-recent
Orogeny:North Kitakami Belt

The is an active fault zone on the Tsugaru Peninsula in Aomori Prefecture and its capital city, Aomori. It is paralleled to east by the west coast of Aomori Bay and to the west by the Tsugaru Mountains, running from north-northwest to south-southeast on the peninsula, through the city of Aomori, and finally extending south toward the Hakkōda Mountains. The zone is made up of three faults: the Aomori Bay West Fault, the Nogiwa Fault, and the Nyunai Fault. The Nyunai fault is a reverse fault.[1] [2]

Earthquakes

No major earthquakes can be directly attributed to the Aomori Bay West Coast Fault Zone during recorded history. There is a history of destructive earthquakes originating in the area, but they could have come from other faults on the peninsula.[3] [4]

It has been estimated that the fault zone could produce an earthquake with a magnitude of 7.3 Mj. There is a 5-10 percent chance of an earthquake occurring on the zone in the next 300 years.[5]

Notes and References

  1. Web site: 青森湾西岸断層帯. ja. Headquarters for Earthquake Research Promotion. 20 June 2019.
  2. Web site: Gravity survey and subsurface structure across the Aomoriwan-Seigan Fault Zone, Northeast Japan. 28 May 2019. 20 June 2019.
  3. Web site: Hatori. Tokutaro. Investigations of the Seismic Intensity and Tsunami of Historical Earthquakes (1964~1810) Occurring in the West Tsugaru to Oga Regions, the Japan Sea. University of Tokyo. 21 June 2019.
  4. Web site: 青森県. ja. 地震調査研究推進本部. 21 June 2019.
  5. Web site: 青森湾西岸断層帯の長期評価について. ja. 地震調査研究推進本部. 14 April 2004. 21 June 2019.