mount mazama is part of the cascade range island arc. it was built up over a period of at least 400,000 years. the caldera was created in a massive volcanic eruption. that led to the lowering of mount mazama around 5700 bc. since that time, all eruptions on mazama are limited to the caldera. lava eruptions later created a central platform, called wizard island. sediments and material from landslides also covered the caldera floor.