Iceland and Hawaii are often mentioned at the same time, because they are the two strongest hot spots in the world. In 1989, T. Neil Irvine of Geophysical Laboratory, Carnegie Institution of Washington, noticed that Iceland and Hawaii are exactly 90° apart. It was a valid reason for him to make an analysis of the mantle currents within the Earth. He started by pointing out two sources of upwelling magma under Iceland and Hawaii, and the other locations forming a rectangular framework of 90° to each direction on the globe. I really appreciate this attempt, and the mathematical relation is a fact. But the convection cell system model here described is different from the one Neil Irvine made. Therefore, to understand why Iceland and Hawaii are 90° apart, the mathematical preconditions have to be derived in two steps, as the angle between the relevant convection rolls is 120°, and the hot spots Irvine referred to are close to different crossings of the convection cell system that lead to the intriguing angle of 90° compared with Earth’s center.
Here you can see the mathematical path of the six ascending division lines of the large convection cells of Earth’s lower mantle. The relationship is revealed to everyone by looking for less than one second!

The relationship between Iceland and Hawaii above main horizontal division lines of large convection cells in Earth’s mantle.
To better understand this in 3D, the convection rolls equator plane is added here to se the vertical aspect. The rolls shown here as circular sections extend to north and south as shown above.
