Another term for spreading plates is divergent plates--when two tectonic plates move away from each other. The Mid-Atlantic ridge is an example, as magma flows upward from the Earth's mantle, through the oceanic crust and becomes lava after it emerges. This action pushes the plates apart and the ridge is the site where this event is occurring. This causes seafloor spreading which helps to renew the sea floor as new crust is formed along with widening of the ocean basin. Because Iceland is located along the Mid-Atlantic ridge, it is splitting along the spreading center between the North American and Eurasian plates. This area has much volcanic activity and ground cracks have widened due the spreading movement of the plates in opposite directions. The rifting is often accompanied by volcanic events in the form of fissure eruptions and earthquake activity. The earthquakes occur due to fracturing and movement of the plates.