Melting glaciers and rising sea levels are the first and foremost base of reason concerning this connection, with the weight distribution along the earth’s crust and over fault lines changing slowly with time. The weight allocation relieves pressure on some parts of the crust and applies it to others, implementing plate shifts as sections of the crust strained by ice rise in a process called isostatic rebound. This same reason can change the weight over undersea volcanoes which have been reported to associate with eruptions, which are then related to earthquakes.
Isostatic ReboundThis isn’t about a couple hundred pounds of ice melting and leaving polar bears scrambling in a panic for still ground, this is about unloading the weight of a sheet of ice a kilometer thick onto a continent, which subsequently can cause serious damage in the way of, no surprise, mega thrust earthquakes. For example, the St. Elias earthquake of 1979 in southern Alaska (magnitude 7.2) had been promoted by melting glaciers in the area. These glaciers near the fault zone had melted substantially since 1899 to be hundreds of meters thinner and many had even disappeared, applying increased pressure on the fault line where the Pacific plate slides under the Continental plate.