Crater Lake Crater Lake began as a composite volcano Mount Mazama huge volcano that collapsed nearly 1,949 feet the Mount Mazama USGS site Mount Mazama 7,700-year-old volcanic eruption Mount Mazama 7700 year old Mazama ash huge volcano that collapsed Crater Lake began as a composite volcano Mazama from USGS Mount Mazama 7,700-year-old volcanic eruption Mount Mazama Crater Lake Mt. Mazama the Mount Mazama USGS site the Mount Mazama USGS site Crater Lake's cataclysm event Mt. Mazama Mount Mazama Mount Mazama U.S. Geological Survey Mount Mazama Crater Lake Mount Mazama Crater Lake's cataclysm event cataclysmic eruption ~7,700 years ago eruption of Mount Mazama