| Ararat(noun, name, volcano, geology) |
| Arayat(noun, name, volcano, geology) |
| Ardoukoba(noun, name, volcano, geology) |
| Arenal(noun, name, volcano, geology) |
| Arenales(noun, name, volcano, geology) |
| Arhab(noun, name, volcano, geology) |
| Arjuno-Welirang(noun, name, volcano, geology) |
| Arxan-Chaihe(noun, name, volcano, geology) |
| Asamayama(noun, name, volcano, geology) |
| Asavyo(noun, name, volcano, geology) |
| Ascension(noun, name, volcano, geology) |
| Ash Pit(expression, name, volcano, geology) |
| Askja(noun, name, volcano, geology) |
| Asosan(noun, name, volcano, geology) |
| Assab Volcanic Field(expression, name, volcano, geology) |
| Asuncion(noun, name, volcano, geology) |
| Ata(noun, name, volcano, geology) |
| Atacazo(noun, name, volcano, geology) |
| Atakor Volcanic Field(expression, name, volcano, geology) |
| Atitlan(noun, name, volcano, geology) |