My dad got back yesterday from a business trip in Oregon where he visited Crater Lake, a caldera. It was formed approximately 7,700 years ago when Mount Mazama (formation began gradually approximately 1.28 million years ago with the first eruptions occurring 725,000-500,000 years ago) erupted and the land around it collapsed and proceeded to fill with water. The area is considered dormant but the island in the center of the lake, called Wizard Island proves past activity. Wizard Island looks like a tiny volcano, but it is actually a cinder cone formed when the ejected lava hardened and formed a solid structure. Researchers believe in the possibly of an eruption in the future because of the magma flows that reside under the lake. Although it would be on a smaller scale than the past eruptions, but still may cause a threat to people in the surrounding areas. Crater Lake is the deepest fresh water lake in the US with a depth of 1,943 feet, and it is part of the Cascade range. The lake is surrounded by pumice rocks, which are glass igneous rocks that has a vesicular texture and I also included a photo of pumice that my dad found. The area around the caldera is covered by igneous rocks brought about from volcanic activity.
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