This is because the decrease in pressure on the earth's surface and crust alters the movement of magma in the area.
As a part of my study abroad program, my classmates and I went on a glacier tour to the largest glacier in Iceland Vatnajökull. I learned so many things about Vatnajökull Glacier from our amazing tour guides. The tour included traveling to multiple ice caves and seeing firsthand where the glacier is breaking and melting away. Our tour guides let us know that one of the ice caves that we were supposed to visit was unaccessible because of the rapid melting of the ice. Our guides also told us that they have to check their glacier tour routes daily with a drone because of how rapidly the ice changes. Depending on what changes have occurred since their last visit to a specific site on the glacier, they assess if it is safe to go back or not. For us, it turned out that only one out of our many stops on the glacier had become unsafe to visit. However, the alarming part of this story is that our tour guides were referring to a very short time scale. Our guides said they could be at a very cool ice cave one day and the next day it would not be accessible anymore. In other words, the ice is changing quickly, even on a day to day scale. When we visited the location where the glacier was breaking off and falling into the glacier lake, the tour guides told us that one of huge piece of the glacier that was sitting in the lake had only recently fallen off. I felt it hard to comprehend how fast the glacier iwas changing when standing in front of one for the first time. Everything about the glacier seemed stagnant, yet there were glacier rivers flowing beneath me without me knowing it.
