D - 1 proposes that sun and moon gravity related forces are acting on the Earth's crust and producing areas where the crust is bent etc. in such a manner that it is weakened. And if an earthquake is about to occur there anyway then that additional strain can trigger it. That area of strain constantly moves towards the west at about the same speed as the sublunar point moves west.

D - 2 propose that the Earth's solid iron core attempts to fly off in a direction away from the moon. But it cannot do that because of the Earth's gravity etc. And those competing process cause the core to exert pressure on the Earth's crust from within the Earth. Those "Pressure Points" also constantly move towards the west at around the same speed as the sublunar point. And if they go through a fault zone area where an earthquake is about to occur then they can add enough additional temporary strain to the fault zone to trigger an earthquake.