Why is Iceland splitting?

Answer 1

Iceland is spreading apart due to the Mid-Atlantic

Ridge that is directly under it. The ridge is constantly bringing up molten material that cools and hardens into new crust, which causes the growth of the country, at a rate of about 10 cm per year.

Answer 2

Iceland sits on the Mid-Atlantic Ridge at the boundary where the North American Plate and the Eurasian plate are pulling apart. Given the present geologic activity, it does not appear that Iceland is going to split. As the eastern and western portions of the island move apart, volcanoes will continue to create new crust. As a result, the island will grow.