Convection currents beneath the plates move the crustal plates in different directions. The source of heat driving the convection currents is radioactivity deep in the Earth's mantle. The mid-oceanic ridges rise 3000 meters from the ocean floor and are more than 2000 kilometers wide surpassing the Himalayas in size. The mapping of the seafloor also revealed that these huge underwater mountain ranges have a deep trench which bisects the length of the ridges and in places is more than 2000 meters deep. Research into the heat flow from the ocean floor during the early 1960s revealed that the greatest heat flow was centered at the crests of these mid-oceanic ridges.
Seismic studies show that the mid-oceanic ridges experience an elevated number of earthquakes.
All these observations indicate intense geological activity at the mid-oceanic ridges. Geomagnetic Anomalies Periodically, the Earth's magnetic field reverses. New rock formed from magma records the orientation of Earth's magnetic field at the time the magma cools. This is evidence for continuous formation of new rock at the ridges. As more rock forms, older rock is pushed farther away from the ridge, producing symmetrical stripes to either side of the ridge.