The large Pacific Plate covers several large scale convection rolls, so the reaction to opposite flow of mantle must be understood. The answer is coupling and de-coupling process with the upper-most rolls. Similar process is known at the bottof of glaciers, sliding over un-even ground. The ice melts when meeting with upheavals, then it does freeze at the other end with less fraction, and then ‘plucks’ the rock below. The process of tectonic plate sliding from east to west, is exactly the same with 1.5° interval. Besides that, every 30° some other change generally occurs, due to a different large scale trend associated with the 30° E-W units of lower mantle rolls.
The volcanic activity resulting when the Pacific Tectonic Plate reaches the main division line, or more accurately the 6° interval of small scale upper rolls east of the main line, shows the local trend of inducing opposite tectonic drift to the main drift. Also, a hub of the convection rolls system is found at this location.
As can be seen, all the up-welling lines are in fact connected into one wholistic system. The Polar Parts are omitted here. The implications of the hub provede an extra pressure/weakness to the area of the Hawaii Islands. Still, do not forget the other factor, horizontal tectonic drift, being opposed east of the red lines of Hawaii.
The 8-formed loops might be difficult to understand at first, as the large scale convection rolls only represent half of that arrangement. The other half of each 8-form is represented on one hand by the small scale rolls found between 265-410 km depth, and on the other hand by the outer core. Traces of core material can therefore be found in magma of countries like Hawaii and Iceland.