https://www.pref.niigata.lg.jp/
https://www.enecho.meti.go.jp/category/resources_and_fuel/enecaree/niigata_fieldwork_report/
tsuda
Creative Commons Attribution-Share Alike 2.0
https://upload.wikimedia.org/wikipedia/commons/2/23/Iwafune-oki_oil_platform_in_Japan.jpg
GasDepositDiagram.jpg: US Energy Information Administration.
Public domain
https://upload.wikimedia.org/wikipedia/commons/d/d1/GasDepositDiagram.svg
Triglav
Creative Commons Attribution-Share Alike 3.0
https://upload.wikimedia.org/wikipedia/commons/2/22/Koshijihara_Plant.jpg
Razashah1
Creative Commons Attribution 3.0
https://upload.wikimedia.org/wikipedia/commons/1/11/Riftxsection.jpg
Ye Tao, Youbin He, Zhongxiang Zhao, Dongsheng Wu, and Qiao Deng
Creative Commons Attribution 4.0
https://upload.wikimedia.org/wikipedia/commons/a/aa/Caprock_Fracture.jpg