Tahiti is amazingly far away from any mainland. It can be compared with Hawaii, because it has a hot spot at Mehetia. The drift of the Pacific Plate creates a chain of islands. The calculated value of directions can be achieved in the same way as for Hawaii:

This is very close to the measured value of tectonic drift, that is N65°W.

The relevant convection rolls division line is found directly under Mehetia.

Here is the calculated value for Hawaii, for a quick comparison 🙂 Note that the calculations are double for Hawaii (NW and NE trending vectors), because the symmetric effect of the two convection rolls layers appears clearly.