When the magma cools and solidifies, the direction and the polarity of the field are preserved in the magnetized volcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallel to the axis of the rift.

• 岩浆冷却并凝固下来后，地磁场的方向和磁极被保留在磁化了的火山岩中，磁场的逆转形成一系列与断层轴线平行的条形磁区。