turn back cave
in granite cave in sootopolis city
It can learn it via the TM but not by level.
It never does; you need to find the hm.
The Pokemon Aggron is the final evolution of the Pokemon Lairon, which evolves at level 42. It is not able to learn the move Earthquake through leveling, but it can be taught Earthquake using TM26 at any time.
If you have a TM. The only ground type moves it can learn is earthquake and magnitude.
at lvl 9 it learns astonish and at lvl 100 it learns earthquake
Pokemon Ruby has Pokemon that Pokemon Sapphire does not and Pokemon Sapphire has Pokemon that Pokemon Ruby does not.
earthquake in Sapphire will be found in seafloor cavern in the room that you battle Archie of team aqua
It is in the cave where Archie of Team Aqua tries to capture Kyogre. Alas you need HM Dive to get there.
There is no Pokemon mansion in sapphire.
claydoll learn hyper beam. self destruct, earthquake, and sandstorm; it can also learn phsychic
He is not in Pokemon: Sapphire. You will not be able to find him. He is in Pokemon: Diamond, Pokemon: Pearl, and Pokemon: Platinum. You will definitely have trouble finding him in Pokemon: Sapphire.