Gaby) Seismic tomography reveals 2 giant “blobs” in the lowermost mantle, one beneath Africa and one beneath the Pacific. They sprawl across 30% of the core-mantle boundary area, with spatial scales on the order of 1000s (km) in width, and up to 1000 km above it. These blobs exhibit lower than average seismic wave speeds, thus they are named "Large low-velocity provinces (LLVPs)”. What is their origin?
A: Internal heating.
Q: (Gaby) What role are they playing, if any, in current Earth changes?
A: Heating up, destabilization, opening up for the reception of cosmic waves.