| Aonoyama(noun, name, volcano, geology) |
| Aoso(noun, name, volcano, geology) |
| Apagado(noun, name, volcano, geology) |
| Apan-Tezontepec(noun, name, volcano, geology) |
| Apas-Navenchauc(noun, name, volcano, geology) |
| Apoyo(noun, name, volcano, geology) |
| Apuseni Mountains(expression, name, volcano, geology) |
| Argowayang(noun, name, volcano, geology) |
| Arintica(noun, name, volcano, geology) |
| Arpacay(noun, name, volcano, geology) |
| Asakusa(noun, name, volcano, geology) |
| Ascotan(noun, name, volcano, geology) |
| Asgura(noun, name, volcano, geology) |
| Ashitaka(noun, name, volcano, geology) |
| Asie(noun, name, volcano, geology) |
| Ata Volcanic Complex(expression, name, volcano, geology) |
| Atherton Volcanic Province(expression, name, volcano, geology) |
| Auca Mahuida Volcanic Field(expression, name, volcano, geology) |
| Aucanquilcha(noun, name, volcano, geology) |
| Aurora-Bodie(noun, name, volcano, geology) |