| Andrus(noun, name, volcano, geology) |
| Aneityum(noun, name, volcano, geology) |
| Aniakchak(noun, name, volcano, geology) |
| Ankaizina Field(expression, name, volcano, geology) |
| Ankaratra Field(expression, name, volcano, geology) |
| Antillanca Group(expression, name, volcano, geology) |
| Antisana(noun, name, volcano, geology) |
| Antofagasta Volcanic Field(expression, name, volcano, geology) |
| Antsiferov Island(expression, name, volcano, geology) |
| Antuco(noun, name, volcano, geology) |
| Aoba(noun, name, volcano, geology) |
| Aogashima(noun, name, volcano, geology) |
| Apagado(noun, name, volcano, geology) |
| Apaneca Range(expression, name, volcano, geology) |
| Apastepeque Field(expression, name, volcano, geology) |
| Apo(noun, name, volcano, geology) |
| Apoyeque(noun, name, volcano, geology) |
| Aracar(noun, name, volcano, geology) |
| Aragats(noun, name, volcano, geology) |
| Aramuaca(noun, name, volcano, geology) |