It's called the East Aftrican Rift,
And geologists have known about it for decades. The rift is similar to, and related to, the Red Sea Rift, which already has opened wide enough to be flooded. Like all tectonic rifts, it is opening slowly, with associated basaltic igneous activity, normal faulting, and filling of the basin by sediment.
While there are differences in the geophysics, these are related to a thinner crust and higher heat flow than normal continental crust.
The idea of more intense magnetism "leaking" out the edges is just silly.