How are bands of magnetism formed on the sea floor?

Bands of magnetism are found on the earth sea floor by the process of seafloor spreading.

Explanation:

As the rising magma from the deep vent of the mid-oceanic ridges. The deposition of magma or lava at the floors of the oceanic beds after solidification leads to the dual magnetic properties that are aligned by the magnetosphere of the earth. This magnetism has several properties and the hard and soft bands of rocks are created as a result of the spreading of lava on both sides of the ridges having reverse magnetic properties. Seafloor spreading and divergence is responsible for the opening up of sea bottoms and hence positively and negatively charges ions are released through this process in lava. Hence the hard and old est rocks are found away from the ridges and soft and smooth rock near the ridges.Studied in Paleomagnetism evidence provided by Harry Hess.

Just do the math, then think