Problem: In addition to rock deposits, what evidence do we have that the eruption that preceded the formation of Crater Lake was very large? The eruption was so large that the volcano became unstable and collapsed, causing Crater Lake to partially empty. The eruption was so large that the volcano became unstable and collapsed, causing the magma chamber under Crater Lake to partially empty. The eruption was so large that the magma chamber under Crater Lake partially emptied, causing the volcano to become unstable and collapse. The eruption was so large that Crater Lake partially emptied, causing the volcano to become unstable and collapse. Need Assignment Help?