Why Brazil Doesn’t Have Significant Earthquakes, Since Its Coast, Once, Was Docked On Africa’s Coast?

At the time of the separation, the Brazilian coast and the African coast WERE the edges of their tectonic plates. There were certainly very strong earthquakes on both continents during the separation. But, as the plates have been emerging from the bottom of the Earth, the material that rose from the mantle replaced the edge and pushed the coast of the two continents away. See the map below: