Instructions
Volcano Badge
Surf east from Cinnabar Island until you reach the Seafoam Islands; then walk into the eastern cave.
Walk up the ladder to enter the gym; then walk up to the first trainer, and initiate a battle. When you defeat him in battle, he will step back and allow you to pass. Walk to the right; then continue battling trainers until a trainer opens the path to Blaine, the gym leader in the middle of the room.
Talk to Blaine to challenge him to a battle. Blaine uses Fire-type Pokemon, and Water-type, Ground-type and Rock-type moves will do extra damage to them. After you knock out all three of Blaine's Pokemon, he will give you the Volcano Badge.
Earth Badge
Exit the cave, fly to Viridian City, and walk into the gym in the northeast corner of town.
Walk forward into the maze, walk all the way to the right wall, and then walk up to the red arrow tile. The red arrow tile will spin you onto a solid tile.
Walk two steps to the left onto a red arrow tile; then walk two steps up onto another red arrow tile.
Take one step to the right; then take one step up onto another red arrow tile.
Take two steps to the right onto another red arrow tile; then take two steps to the right to step on the final red arrow tile.
Walk up to Blue, the gym leader, and challenge him to a battle. Unlike most gym leaders, Blue uses several different types of Pokemon on his team, so each of his Pokemon have different strengths and weaknesses. Use Bug-type moves against Blue's Exeggutor, use Water-type moves against his Rhydon and Arcanine, use Electric-type moves against his Gyarados and Pidgeot and use Psychic-type or Flying-type moves against his Machamp. Once you defeat Blue's team of six Pokemon, he will award you the Earth Badge.