Oarasawa Formation
Obama Formation
Obara Tonalite
Obata Formation
Obatake Granodiorite
Obiki Unit
Oboke unit
Obusuma Group
Ochiai Conglomerate Formation
Ochiai Formation
Odakegawa Lavas
Odokorogawa Formation
Ofuji Lava
Ofuna Formation
Ofuna Mudstone Formation
Ofunato Subbelt
Oganomachi Formation
Oganomachi Group
Ogawa Formation
Ogigakura Tuff
Ogikubo Sandy Mudstone Member
Ogi Quartz Diorite
Ogo Pumice Flow Deposit
Ohachidaira Caldera Eruption Deposit
Ohachimori Amphibolites
Ohashi Formation
Ohatayama Lavas
Ohatayama Pyroclastic Rocks
Ohirayama Unit
Ohno Formation
Ohno Volcanic Rocks
Ohyamashimo Formation
Ohzone Formation
Oi Formation
Oishi Formation
(ŠâŽè)
Oishi Formation
(Œä‰×–gƒ†ƒjƒbƒg)
Oishigawa-futamata Lavas
Oishigawa Lavas
Oishigawa Pyroclastic Flow
Oishigawa Volcanic Rocks
Oishi Lava
Ojo Formation
Okamotsugawa Complex
Okamura Formation
Okanaro Group
Okawaratoge Pyroclastics
Okinazawa Basalt Member
Okuda Formation
Okuda Tuff Bed
Oku Formation
Okukurobe Granite
Okumatashiro Granite
Okushibetsu Plutonic Complex
Okuwa Debris Avalanche Deposit
Okuwahara Sandstone Member
Okuyama Formation
Okuzure Formation
Old dune
, Shonai sand dunes
Older Atosanupuri Volcano
Older Inbi stage intrusive rocks
Older Kitadake Volcano
Older Minamidake Volcano
Older Ryoke Granitoids
Older stage Hokusatsu Volcanic Rocks
Older stage Nansatsu Volcanic Rocks
Older Stratovolcano
(Akagi Volcano)
Oldest stage Nansatsu Volcanic Rocks
Omae Unit
Omagari carbonate islet
Omagari Formation
Omama Complex
Omi Complex
Omi Limestone
Omi Metamorphic rocks
Omine Acidic Tuff Bed
Omine Pyroclastic Flow Deposit
Omine Welded Tuff Bed
Omma Formation
Omma Sandstone Formation
Omori Formation
Omuro Lava
Onagata Subunit
Onbetsu Group
Onigatsuji Mudstone and Sandstone Member
Onishi Conglomerate Member
Onma Formation
Onma Sandstone Formation
Onnagawa Formation
Onzawa Facies
Oppata Granite
Oritate Conglomerate
Oritate-toge Conglomerate
Orito Formation
Oro Formation
Orojidani Formation
Osaka Dacite
Osaka Group
Osakamoto Formation
Osakatoge Complex
Osakatoge Formation
Osakihana Dacite
Osawa Formation
(Inai Group)
Osawa Formation
(Tanzawa Group)
Osawaguchi Tuff Member
Osawa Tuff Formation
Oshidomari Lava
Oshidomari-pon'yama Lava Dome
Oshima Belt
Oshima-Kojima volcano
Oshimayama Subunit
Oshimojo Formation
Oshirasawa Granite
Osoushinai Formation
Osumi Granodiorite
Otakidani Formation
Otani Lavas
Otanoshike Formation
Otogawa Formation
Otoge Volcanic Complex
Otonashigawa Belt
Otonashigawa Group
Otori Formation
Otori Unit
Otsukamiya Granite
Oyabe Formation
Oyabe Mudstone Formation
Oyakkotsu Lava Dome
Oyamada Formation
Oyama Formation
, Hayama Group
Oyama Formation
, Tokai Group
Oyama Subgroup
Oyama Tuffaceous Sandstone Formation
Oyashirazu Formation
Oyashirazu Volcanic Rocks
Ozenji Formation