* Volcanic Activity: The area where Mount Mazama stands was a site of intense volcanic activity for millions of years.

* Caldera Formation: Around 7,600 years ago, Mount Mazama, a stratovolcano, experienced a cataclysmic eruption. This eruption was so powerful that it emptied the volcano's magma chamber, causing the mountain to collapse in on itself. This collapse created the massive crater that is now known as Crater Lake.

* Crater Lake Formation: The caldera filled with rainwater and melted snow, eventually forming the deep, pristine Crater Lake we see today.

In summary, Mount Mazama was formed over a long period of volcanic activity culminating in a massive eruption that led to its collapse and the formation of Crater Lake.