- A-1, Tanohata Granite
- A I, Tappi Volcanic Rocks
- A-2, Tanohata Granite
- A II, Tappi Volcanic Rocks
- A-3, Tanohata Granite
- A III, Tappi Volcanic Rocks
- A-4, Tanohata Granite
- A IV, Tappi Volcanic Rocks
- A-5, Sr-poor, Tanohata Granite
- A-5, Sr-rich, Tanohata Granite
- A-6, Tanohata Granite
- A-7, Tanohata Granite
- AK
- Ak1, Akan volcano
- AK-1, Akita-Komagatake volcano
- Ak2
- Ak3
- Ak3pfa
- Ak3pfl
- Ak4
- Ak5
- Ak6
- Ak6-a
- Ak6-apfa
- Ak6-apfl
- Ak6-b
- Ak6-c
- Ak6-d
- Ak7
- Ak7-a
- Ak7-b
- Ak7-c
- Ak7-cpfa
- Ak7-cpfl
- Ak7-d
- Ak7-e
- Ak8
- Ak9
- Ak9-a
- Ak9-b
- Ak9-c
- Ak10
- Ak11
- Ak12, Hokkaido
- Ak-12, Gifu pref.
- Ak12-a
- Ak12-b
- Ak12-c
- Ak13
- Ak13-a
- Ak13-b
- Ak14
- Ak14-a
- Ak14-b
- Ak14-c
- Ak14-d
- Ak14-e
- Ak14-f
- Ak14-g
- Ak15
- Ak15-a
- Ak15-b
- Ak15-c
- Ak15-d
- Ak15-e
- Ak15-f
- Ak16
- Ak17
- Akabakyo Lava
- Akabane Body
- Akabane Formation
- Akabane Member
- Akabane Silt Facies
- Akabane Terrace Deposits
- Akabira Formation
- Akada Formation, Nagano pref.
- Akada Formation, Kumamoto pref.
- Akadake Lava
- Akada Lava
- Akadani Welded Tuff
- Akadaredani Lavas
- Akagami Formation
- Akagami Shale Formation
- Akagawa Lavas
- Akagidaira Lava
- Akagidairashita Lava
- Akagine Rhyolite
- Akagi Volcano
- Akagiyama Gravel
- Akagizawa Dikes
- Akahage Lava
- Akahageyama Formation
- Akahani volcano
- Akahira Group
- Akai Pyroclastic Flow Deposit
- Akaishidake Formation
- Akaishi Formaiton
- Akaishigawa Diorite Porphyrite
- Akaishi Group
- Akaishi Lava
- Akaishi Welded Tuff
- Akaiwa Formation, Otaru
- Akaiwa Formation, Tetori Group
- Akaiwa Subgroup
- Akakura Caldera Fill Deposit
- Akakuradake 1st-stage Lava
- Akakuradake 2nd-stage Lava
- Akakuradake 3rd-stage Lava
- Akakuradake 3rd-stage Pyroclastic Rocks
- Akakuradake 4th-stage Lavas
- Akakuradake Lava
- Akakuradake Pyroclastic Rocks
- Akakura Pyroclastic Flow Deposit
- Akakura Tuff
- Akakura Tuff Member
- Akakurazawa Mudflow Deposit
- Akakurazawa Pyroclastic Flow Deposit
- Akakurazawa stage
- Akakuzuregawa Lava
- Akakuzureyama Andesite
- Akakuzureyama Lava
- Akakuzurezawamigimata Lava
- Akamori Formation
- Akamori Tuff Breccia Member
- Akana Granodiorite
- Akandana Dome Lava
- Akandana volcano
- Akandana Pyroclastic Rocks
- Akan Pyroclastic Fall Deposit
- Akanuma Formation
- Akan volcano
- Akan Welded Tuff
- Akappage volcano
- Akarutoge Pyroclastic Flow Deposit
- Akasaka Formation
- Akasaka Limestone
- Akasaki Formation
- Akasaki Siltstone Member
- Akasawa Mud Member
- Akashiba Formation
- Akashi Formation
- Akashima Formation
- Akashima Lavas
- Akashina Formation
- Akashio Formation
- Akashio Loam
- Akataki Complex
- Akataki Formation
- Akataki Lava, Fukushima pref.
- Akataki Lavas, Nagano pref.
- Akatani Formation
- Akatazawa Dacite
- Akatsuka Rhyolite
- Akatsuki Ash Layer
- Akatsukidai Member
- Akatsukikaido Member
- Akaura Sandstone Member
- Akaya Shale Formation
- Akazakinomine Lava
- Akazakinomine volcano
- Akazawa Formation
- Akazawa Lava, Iwate pref.
- Akazawa Lava, Nagano pref.
- Akebihara Member
- Akebono Conglomerate
- Akebono Formation
- Akebono Group
- Akechi Formation
- Akedo Terrace Deposits
- Akemi Formation
- Akenobe Formation
- Akeshidani Mass
- Akeshidani Volcanic Rocks
- Aketo Formation
- Aketo Sandstone
- Akeyo Formation
- Akezawa Formation
- AK-g
- AK-h
- Akibadai Member
- Akibasaki Porphyritic Granite
- Aki Group
- Akikawa Formation
- Akikawa Lapilli
- Akima Formation
- Akimotoko Pyroclastic Flow Deposit
- Akira Formation
- Akiruppara Formation
- Akita Coastal Dune
- Akita-Komagadake volcano
- Akita-Oshiromori Volcanic Products
- Akiu Formation
- Akiu Group
- Akiyama Formation
- Akiyamago Formation
- Akiya Scoria Cone
- Akiyoshi Belt
- Akiyoshi Limestone
- Akiyoshi Limestone Group
- Akiyoshi terrane
- Ak-K
- Akka Belt
- Akka Formation
- Akkagawa Formation
- Akka Limestone
- Akka - Tanohata Sub-belt
- Akka Unit
- Akka Volcanic Ash
- Ako Formation
- Akogi Tephra
- Ako Lava
- Ako Welded Tuff
- Akuda Mass
- Akusa Formation
- Akusa Welded Tuff
- Akusedani Formation
- Am1
- Am4
- Am19
- Am28
- Am40
- Am56
- Am61
- Am78
- Am94
- Am98
- Amabiki Body
- Amabiki Granite
- Amabikiyama Granite
- Amadanai Formation
- Amaderahara Formation
- Amaderahara Golf Course Formation
- Ama Formation, Aichi pref.
- Ama Formation, Shimane pref.
- Amagase Formation, Tokyo
- Amagase Formation, Nara pref.
- Amagikogaseki Lava
- Amagiri Sandstone and Mudstone Member
- Amagi volcano
- Amago Intrusive Rocks
- Amaharashi Tuffaceous Sand Member
- Amaike Pumice
- Amaike-toho Lava
- Amaikeyama Lava
- Amakata Formation
- Amakata Sandstone Member
- Amakazariyama Volcanics
- Amami Quartz-diorite
- Amamizukoshi Tuff
- Amamizuyama Formation
- Amanokawara Formation
- Amanomiya Sandstone
- Amatsu Formation
- Amatsu Mudstone Formation
- Amazakai Pyroclastic Flow Deposit
- Amedaki Andesite
- Amedaki Gravel Bed
- Amegi Basalt
- Amegochigawa Formation
- Amehatagawa Formation
- Amehatagawa Group
- Amehata Granite
- A Member, Gumizaki Formation
- a Member, U-II Formation, Himenoura Group
- a Member, U-III Formation, Himenoura Group
- a Member, U-IV Formation, Himenoura Group
- Amenomiya Formation
- Amg slump
- Amidadake Lava
- Amidagawa Pyroclastic Flow Deposit
- Amidase Pyroclastic Flow Deposit
- Amigasayama Lava
- Amino Formation
- Amo Formation
- Amo Granite
- Amura Formation
- AS23-25
- AS-4
- As-A
- Asabu Sandstone Member
- Asadagiri Sands and Mud
- Asadokoro Formation
- Asagai Formation
- Asagara Mass
- Asagarano Sands Member
- Asagarano Tephra
- Asagaridani Granodiorite
- Asagaya Mudstone Member
- Asago body
- Asahi Body
- Asahidaira Lava and Pyroclastic Rock
- Asahidake South Lavas
- Asahidake Subgroup
- Asahidake Summit Pyroclastic Rock
- Asahidake Upper Pyroclastic Rock and Lava
- Asahidake volcanic edifice
- Asahidake West Lower Lavas
- Asahidake West Upper Lava and Pyroclastic Rock
- Asahidaki Basalt
- Asahidaki Lava
- Asahi Formation
- Asahigawa Formation
- Asahimori Rhyolite
- Asahi Mountains Younger Granites
- Asahinadake Lava
- Asahinadake volcano
- Asahiyama Agglomerate Beds
- Asahiyama Andesite Member
- Asahiyama Formation, Nagano pref.
- Asahiyama Formation, Tokyo
- Asahiyama Lava, Mount Karitasan
- Asahiyama Lava, Mount Shigayama
- Asahiyama Shell Bed
- Asahiyama Terrace Deposit
- Asaji Metamorphic Rocks
- Asakariyama Lava
- Asakawa Formation, Nagano pref.
- Asakawa Formation, Ibaraki pref.
- Asakawa Member
- Asakawa Mudstone Member
- Asakegawa Sandstone and Mudstone Member
- Asakura Granodiorite
- Asakusa volcano
- Asakusazawa Pyroclastic Flow Deposit
- Asama-Eboshi volcanoes
- Asamagatake Mass
- Asamahara Rhyolite
- Asamatoge Sandstone and Mudstone Facies
- Asamatoge Sandstone and Mudstone Member
- Asamayama volcano
- Asamigawa Member
- Asanai Terrace Deposit
- Asarifuji Rhyolite
- Asari Group
- Asashiro Tephra
- As-B
- As-BP
- As-C
- A scoria cone, Miyakejima volcano
- As-MP
- As-YP
- Aseishigawa Basalt
- Asemigawa Unit
- Ashibuchi Complex
- Ashidaira Lava
- Ashidaira Pyroclastic Rocks
- Ashidani Formation
- Ashigara Group
- Ashigawa Formation
- Ashigeta Formation
- Ashihara Body
- Ashiharahira type, Miyako Granite
- Ashi-jima Mass
- Ashikaga Body
- Ashikajima Formation
- Ashikawa type
- Ashikita Group
- Ashimatagawa Group
- Ashino Pyroclastic Flow Deposit
- Ashio Belt
- Ahio Rhyolite
- Ashio Rhyolitic Welded Tuff
- Ashitani Formation, Nagano pref.
- Ashitani Formation, Gifu pref.
- Ashiu Sandstone Member
- Ashiyamada Formation
- Ashizawa Formation, Yamagata pref.
- Ashizawa Formation, Futaba Group
- As-K
- Aso-1 Pyroclastic Flow Deposits
- Aso-2 Pyroclastic Flow Deposits
- Aso-3 Pyroclastic Flow Deposits
- Aso-4
- Aso-4A
- Aso-4B
- Aso-4 Pyroclastic Flow Deposits
- Aso-4T
- Asogawa Shale and Tuff Member
- Aso Group
- Asojima I Tuff
- Asojima II Tuff
- Asojima Formation
- Aso Limestone
- Asou Formation
- Aso volcano
- As-Sj
- Asso Formation
- As-SP
- As-UG
- Asuna Granite
- Asuwa Formation
- Asuwa Group