• Ia
• I Alternation of Sandstone and Mudstone

• Ib
• Ibaragawa Formation
• Ibaragi Granitic Complex
• Ibaraki Clay Formation
• Ibaraki Lavas
• Ibohara Formation
• Ibonai Terrace Deposit
• Ibora Tephra
• Ibukiyama Limestone Formation

• Ic
• IC
• Icchoda Formation
• Icchoda Member
• Ichida Granite
• Ichido Mudstone and Sandstone Member
• Ichihara I Terrace Deposits
• Ichihara II Terrace Deposits
• Ichihara III Terrace Deposits
• Ichihasama Pumice
• Ichiino Clays Member
• Ichijiku Formation
• Ichijo Andesite
• Ichijuku Formation
• Ichikawadaimon Formation
• Ichiki Acidic Volcanic Rocks
• Ichinanbayama Lava
• Ichinohara Formation
• Ichinohara Tephra
• Ichinohe Granite
• Ichinohe Pluton
• Ichinoike volcano
• Ichinokawa Formation
• Ichinokoshi Lavas
• Ichinomata Basalt
• Ichinomatakawa Lavas
• Ichinomatazawa Basalt Member
• Ichinomegata maar
• Ichinomiya Gravel Bed
• Ichinonohara Tuff Member
• Ichinono Member
• Ichinosaka Lava
• Ichinosaka Tuff
• Ichinosawa Body
• Ichinosawa Formation
• Ichinosawa Granite
• Ichinosawa Pyroclastic Flow Deposit
• Ichinosawa Tephra
• Ichinosawa Unit
• Ichinosawa Welded Tuff
• Ichinose Formation, Iiyama, Nagano pref.
• Ichinose Formation, Matsumoto, Nagano pref.
• Ichinose Formation, Yamanashi pref.
• Ichinose Formation, Fukui pref.
• Ichinose Formation, Gifu pref.
• Ichinose Group
• Ichinose Member
• Ichinose Rhyolite
• Ichinose Sandstone and Conglomerate Facies
• Ichinose Sandstone and Conglomerate Member
• Ichino Tephra
• Ichinotani Formation
• Ichinotogawa Pyroclastic Flow Deposit
• Ichinowatari Formation
• Ichinoya Formation
• Ichio Formation
• Ichiriboki olistostrome
• Ichirozawa Lava
• Ichishi Group

• Idaira Formation
• Idaka Member
• Ida volcano
• Idekami Formation
• Idodake Lava
• Idodake Pyroclastic Rocks
• Idodakesancho Explosion Breccia
• Idodakesancho lava dome
• Idoirisawa Member
• Idonnappu Belt
• Idonnappu Zone
• Idozawa Formation, Gunma pref., Miocene
• Idosawa Formation, Gunma pref., Triassic
• Idosawa Formation, Tokyo

• Ieda Group
• Ieki Formation
• Ieki Sandstone and Mudstone Member
• Ie Unit
• Ieyama Formation

• Iga-Aburahi Formation
• Iga Formation
• Igarashi Lava I
• Igarashi Lava II
• Igarashi Lava III
• Igarashi Lava IV
• Igarashi Lava V
• Igarashi Lava VI
• Igarashi Lava Dome
• Igarashi Pyroclastic Flow Deposit
• Igarashisekishoku Lava
• Iga Sands and Gravels Member

• IH
• Ihara Group
• Iheya Unit
• Ihoridanitoge Conglomerate
• Ihoridanitoge Conglomerate Member

• Iida Diatomaceous Mudstone Formation
• Iida Formation, Ishikawa pref.
• Iida Formation, Chichibu city, Saitama pref.
• Iida Formation, Ogawa city, Saitama pref.
• Iidesan Granodiorite
• Iigamori Lava
• Iijichuo Lava Dome
• Iijima Tuff
• Iiji volcano
• Iikura Conglomerate Member
• Iimori Formation
• Iimori Unit
• Iimoriyama Lava
• Iimoriyama parasitic cone
• Iimuro Formation
• Iinoya Formation
• Iitomi Formation
• Iizawa Formation
• Iizuka Diatomaceous Mudstone Formation
• Iizuka Formation
• Iizume Formation, upper
• Iizume Formation, lower
• Iizuna Basalts
• Iizuna Formation
• Iizuna Lava
• Iizuna proper strato-volcanic products
• Iizuna Pyroclastic Flow Deposit
• Iizuna Tuff
• Iizuna Volcanic Ash
• Iizuna Volcanic-Fan Deposit
• Iizuna volcano
• Iizuna volcano caldera Lacustrine Deposit
• Iizunayama Lava, Iizuna city
• Iizunayama Lava, Takayama city

• Ij
• Ijimi Granite
• Ij-MO
• IjT

• Ik
• Ikadaba Terrace Deposit
• Ikadachi II
• Ikadachi Formation
• Ikarigaseki caldera
• Ikarigaseki Formation
• Ikari Sandstone Member
• Ikaruga Member
• Ikb-1
• Ikeda Formation
• Ikego Formation
• Ikeda Group
• Ikego Pyroclastic Formation
• Ikejirigawa Debris Avalanche Deposit
• Ikejirigawa Mudflow
• Ikenohara Coarse Sandstone Member
• Ikenohara Formation
• Ikenosawagawa Lava
• Ikenosawa Lava
• Ikenotaira-bokujo Lavas
• Ikenotaira Lava
• Ikenotaira pyroclastic cone
• Ikenouchi I Tephra
• Ikenouchi II Tephra
• Ikenouchi III Tephra
• Ikenouchi Formation
• Ikenoue Formation
• Ikenowaki Tephra
• Ikenowaki Terrace Deposits
• Iketsuki Tuff
• Ikezuki Tuff
• Ikime Formation
• Ikobe Gravel Member
• Ikokuma Agglomerate Member
• Ikokuma Andesites
• Ikokuma Formation
• Ikudo Formation
• Ikumo Caldera
• Ikumo cauldron
• Ikumo Formation
• Ikuno Group
• Ikunoura Formation
• Ikuridani Formation
• Ikuridani Group
• Ikushunbetsu Formation
• Ikuta Formation
• Ikuta Granite

• Imabetsu Andesites
• Imabetsu Volcanic Rocks
• Imaichi Pyroclastic Flow Deposit
• Imaidani Group
• Imai Formation
• Imai Gravels
• Imaizumi Formation
• Imaizumigawa Formation
• Imaizumi Sandstone and Conglomerate Member
• Imajo Complex
• Imajo Formation
• Imajuku Formation
• Imajuku Sandstone Member
• Imakuma I Tephra
• Imakuzure Formation
• Imasaki Lava
• Imaura Group
• Imizu Formation
• Imogadaira Formation
• Imogawa Member
• Imogawa Tuff
• Imokubo Conglomerate Formation
• Imokubo Formation
• Imokubo Gravel Formation
• Imono eclogite
• Imono mass
• Imosawagawa Formation
• Imoya Body
• Imozu Conglomerate Member

• Inada Granite
• Ina Formation
• Inagatani Gravel Bed
• Inagawa Complex
• Inagawa Granite
• Inagawa Granodiorite
• Inagawa Group
• Inagawa Sandstone Member
• Inagi Formation
• Inagobokujo Lava
• Inagodake Lavas
• Inagodake Pyroclastic Flow Deposit
• Inagoe Formation
• Ina Group
• Inaguratoge Andesite
• Inai Group
• Inakozawa Formation
• Inakozawa Mudstone Formation
• Inakuradake Lava
• Inambajima volcano
• Inamura Andesite
• Inamura Formation
• Inaritai Lacustrine Deposit
• Inarizaka Loam
• Ina Sandstone Member
• Inase Formation
• Inashibetsu Tuff
• Inashibetsu Tuff Member
• Inatori Mudflow Deposit
• Ina Tuff Breccia Member
• Inawashiro Calderas
• Inbi stage volcanic rocks
• Ine Andesite
• Ine Group
• Inekoki Formation
• Initial stage, Rishiri volcano
• Initial volcanic edifice
• In-Kt
• In-KT
• In-KTa
• Innai Tuff
• Innai Tuff Member
• In-Ny
• Inogama Formation
• Inoguchi Member
• Inohana Tonalite Porphyry
• Inotani Alternation Member
• Inotani Alternation of Sandstone and Shale Member
• Inotani Formation
• Inou Volcanic Ash
• Inp
• InP
• Intrusive pyroclastic rocks, Kumano Acidic Rocks
• Intrusive Pyroclastic Rock, Ikumo caldera
• Inubo Group
• Inubozaki Formation
• Inugami Granite Porphyry
• Inugasako Breccia Member
• Inugashirayama Complex
• Inui Group
• Inukura Debris Flow Deposit
• Inukura Lava
• Inukura volcano
• Inukurayama Lava
• Inumodorikyo Complex

• Io
• Iodake Crystalline Schist
• Iodakekabu Lava
• Iodakejobu Lava
• Iodake Lava, Aomori pref.
• Iodake Lavas, Aomori pref.
• Iodake Volcanic Rocks, Nagano pref.
• Iodake Welded Tuff
• Iogawa Lava
• Ioridanitoge Formation
• Iori Formation
• Iori Granodiorite
• Iozawa Metasomatic Rocks
• Iozen Formation

• Ippongihara Debris Avalanche Deposit
• Ippongi Lapilli Member
• Ipponmatsuyama Formation

• Ir1 Pyroclastic Flow Deposit
• Irahara Granodiorite
• Irakawa Formation
• Irawara Granodiorite
• Iratsu mass
• Irg
• Iriai Formation
• Irieno Formation
• Iridogawa Lava
• Iriishikura? Formation
• Iriki Pyroxene Andesite
• Irimazawa Member
• Irimizuzawa Green Tuff
• Irinotaira Formation
• Iriomote Formation
• Irisawa Formation
• Irishiken Granite
• Irishiken Granodiorites
• Irisugaya Formation
• Iritamo Rhyolites
• Iritono mass
• Iriyamagawa Tuff
• Iriyama Sandstone Facies
• Iriyama Sandstone Member
• Iriyamazawa caldera
• Iriyamazawa Formation
• Iriyamazawa Tuff
• Irohazaka Welded Tuff
• Irozaki Andesite
• Irozaki Tuff Breccia Formation
• Iruma Formation, Saitama pref.
• Iruma Formation, Shimane pref.

• Is
• IS-1
• IS-2
• Isabu Formation
• Isaki Welded Tuff
• Isatomae Formation
• Isawagawa Fan Deposit
• Isawagawa Formation
• Isbt
• Isegi Sandstone and Mudstone Member
• Isekambe Formation
• Isekanbe Member
• Ise Metamorphic Rocks
• Iseyama Formation
• Isg-c
• Isg-e
• Isg-f
• Isg-g
• Isg-h
• Ishiai Member
• Ishiba Formation
• Ishibatake Conglomerate Member
• Ishida Formation, Aichi pref.
• Ishida Formation, Shiga pref.
• Ishido Formation, Saitama pref.
• Ishido Formation, Chiba pref.
• Ishido Gravels Member
• Ishido Group
• Ishido Siltstone Formation
• Ishifune Formation
• Ishifutagarisawa Formation
• Ishifutagarisawa Mudstone Member
• Ishigami Formation, Saitama pref.
• Ishigami Formation, Tokyo
• Ishigami Terrace Deposit
• Ishigamiyama Tuff
• Ishigami zone
• Ishigamori Dacite
• Ishigure Formation
• Ishigurekitayama Tephra
• Ishigure Tephra
• Ishihagegawa Lava
• Ishihagegawa Volcanic Rocks
• Ishiji Alternation
• Ishiji Sandstone
• Ishiji Sandstone and Mudstone Alternation
• Ishikari Dune Sand
• Ishikari Group
• Isihkawa mass
• Ishiki Formation
• Ishikiriyama Granodiorite
• Ishikoshi Andesite
• Ishikoyama Granite
• Ishikura Formation
• Ishikurayama Formation
• Ishimaki Formation
• Ishimakiyama Unit
• Ishimoriyama Tuff Breccia Member
• Ishinazaka Terrace Deposit
• Ishiwaritoge Formation
• Ishiwariyama Body
• Ishiyakushi Formation
• Ishiyama I Tephra
• Ishiyama II Tephra
• Ishiyama Gravels Member
• Ishiyama Lava
• Ishiyama Lava Dome
• Ishiyama Limestone
• Ishiyama Member
• Ishizaka Formation
• Ishizaka Rhyolite
• Ishizaka rhyolitic lava
• Ishizaka Tuff
• Ishizaki Formation
• Ishizawagawa Formation
• Ishizuchi Group
• Ishizuchi Igneous Rocks
• Isoai Formation
• Isodayama Formation
• Isojirozawa Shale Formation
• Isokusa Formation
• Isomatsu Formation
• Isondani Conglomerate
• Isoo I Tephra
• Isoo II Tephra
• Iso Pyroclastic Flow Deposit
• Iso Tuffaceous Sandstone Member
• Isoura Formation
• Issaikyo Unit
• Issaikyoyama volcano
• Isso Conglomerate Member
• Isso Formation
• Isozaki Formation
• Issha Tephra
• Isshiki Tuff
• Isumi 1 Terrace Deposits
• Isumi 1 (Yoshifu) Terrace Deposits
• Isumi 2 Terrace Deposits
• Isumi 3 Terrace Deposits
• Isumigawa Shell Bed

• Itabashi Formation
• Itabatake Formation
• Itado Andesite
• Itadome Formation
• Itadori Mass
• Itahana Formation
• Itami Formation, Shizuoka pref.
• Itami Formation, Hyogo pref.
• Itanakogawa Formation
• Itanami Formation
• Itanami Group
• Itaoroshitoge Formation
• Itaoroshitoge Siltstone Member
• Itaoroshitoge Tuff and Shale Member
• Itaya Alternation Member
• Itaya calderar
• Itaya Formation (Yamagata)
• Itaya Formation (Toyama)
• Itayama Tuff
• Itaya Member
• Itaya Sandstone and Siltstone Member
• Itaya Tuff
• Itazawa Lahar deposit
• Itchoda Formation
• Itoi Pumice Flow Deposit
• Itokaya Lava
• Itokaya Pyroclastic Flow Deposit
• Itoman Formation
• Itonashi volcano
• Itoo Formation
• Ito Pumice Flow Deposit
• Ito Pyroclastic Flow Deposit
• Itoshima Granodiorite
• Itoshiro Group, Hida Gaien Belt
• Itoshiro Subgroup, Tetori Group
• Itsukaichimachi Group
• Itsukamachi Sandstone
• Itsuki Formation
• Itsuki Shale Member
• Ittori Formation
• Itukamati Muddy Sands
• Itukamati Sandstone Member

• Iu Formation

• IW1
• IW2
• Iwade Formation, Tochigi pref.
• Iwade Formation, Wakayama pref.
• Iwadeyama Pumice
• Iwadono Formation
• Iwadonozawa Formation
• Iwagamiyama Formation
• Iwagoyama Granite
• Iwahata Limestone Member
• Iwahatayama Lava
• Iwaibukuro Formation
• Iwaidani Lava
• Iwaidani Mylonite
• Iwai Formation
• Iwaine Formation
• Iwaine Group
• Iwaisawa Lava
• Iwaizaki Formation
• Iwaizaki Limestone
• Iwaizumi Belt
• Iwaizumi Belt
• Iwaizumi Formation
• Iwaizumi Group
• Iwajuku Terrace Deposit
• Iwaki Formation, Shiramizu Group
• Iwaki Formation, Chichibu Belt
• Iwakisan Volcaniclastic Rocks
• Iwakisan volcano
• Iwaki Terrace Deposits
• Iwakokekotani Lavas
• Iwakoyama Formation
• Iwakuni Granite
• Iwakura Formation
• Iwakura Lava
• Iwakura Pyroclastic Flow Deposit
• Iwakurayama Body
• Iwakurayama Complex
• Iwakurayama Rhyolite
• Iwamatsu Formation
• Iwami Formation
• Iwami Granite
• Iwamizawa Formation
• Iwamori Tephra
• Iwamura Group
• Iwamuro I Tephra
• Iwamuro II Tephra
• Iwamuro Clays Member
• Iwamuro Formation
• Iwamuro Sands Member
• Iwamurotoho Ultramafic Rocks
• Iwanamesawa Mudstone Member
• Iwane Rhyolite
• Iwano Formation
• Iwanosawa Formation
• Iwaobashi Sandstone Member
• Iwaodaki Tuffaceous Sandstone Member
• Iwao Formation
• Iwaoji Formation
• Iwappara Lava
• Iwasaka Formation
• Iwase Formation
• Iwase Granodiorite Porphyry
• Iwase Tuff
• Iwashimizu Complex
• Iwashimizu Conglomerate Formation
• Iwashimizu Formation
• Iwashimizu Lava
• Iwashita Andesites
• Iwatake Glaciolacustrine Deposits
• Iwatake stage
• Iwatakeyama Welded Tuff
• Iwataki Welded Tuff
• Iwate-Fudotai Tephra
• Iwate-Kariya Scoria
• Iwate-Oide Scoria
• Iwate-Okawakaitaku Scoria
• Iwate-Shirishida Scoria
• Iwate-Suko Scoria
• Iwate volcanic group
• Iwate volcano
• Iwatoyama Formation
• Iwatsubodani Formation
• Iwatsubodani Lava
• Iwatsubodani Pyroclastic Rocks
• Iwatsubodanigentou Lava
• Iwatsuboyama Lava
• Iwatsuboyama volcano
• Iwatsuboyama Welded Tuff
• Iwaya Formation
• Iwaya Granite
• Iwayakan'non stratovolcano
• Iwayakannon Lava
• Iwayama Lavas
• Iwayama Tephra
• Iwayatani Member
• Iw-Fd Tephra
• Iw-KS Tephra
• Iw-OdS Tephra
• Iw-OkS Tephra
• Iw-ph1 Tephra
• Iw-ph2 Tephra
• Iw-ph3 Tephra
• Iw-ph4 Tephra
• Iw-ph5 Tephra
• Iw-ph6 Tephra
• Iw-ph7 Tephra
• Iw-ph8 Tephra
• Iw-ph9 Tephra
• Iw-ph10 Tephra
• Iw-ph11 Tephra
• Iw-ph12 Tephra
• Iw-SS Tephra
• Iw-SuS Tephra
• Iw-W6a Tephra
• Iw-W6b Tephra
• Iw-W6c Tephra
• Iw-W6d Tephra
• Iw-W7a Tephra
• Iw-W8a Tephra
• Iw-W8b Tephra
• Iw-W9 Tephra

• Iy

• Iz
• Iz1 Pyroclastic Flow Deposit
• Iz2 Pyroclastic Flow Deposit
• Izaki Olistolith
• Izaku Pyroclastic Flow Deposit
• Izeki Formation
• IZ-FM
• Iz-Kt
• Iz-KTa
• Iz-Ny
• Izumi Formation
• Izumigatake volcano
• Izumi Group, Kyoto pref.
• Izumi Group, Osaka pref.
• Izumi Terrace Deposits
• Izumiyatsu Member
• Izumiyatsu Mollusca Belt
• Izu-Oshima 2013 Lahar Deposit
• Izu-Oshima S₂-c Lahar Deposit
• Izu-Oshima volcano
• Izuo Unit
• Izuriha Complex
• Izuru Formation
• Izuruha Acidic Rocks
• Izuruha Plutonic Rocks
• Izusan Dacite