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Although strong remote aftershocks are exceedingly rare, their rate increased fivefold during the six days following the 2012 east Indian Ocean earthquake, perhaps as a result of the strike-slip nature of the 2012 event or a build up of close-to-failure nucleation sites.

Africa is splitting apart down the East African Rift. An analysis of the relative motion of the tectonic plates involved allows the rate of continental rifting to be estimated.

The absolute motion of the Pacific plate has been nearly constant during the past 15 Myr, but Epp1 recognized that some change took place between 15 Myr and the present, and tentatively chose 1 Myr for the time of the change. Cox and Engebretson2 found a change in Pacific absolute motion based on hotspot tracks and a change in Pacific–Antarctic relative motion. The Pliocene deformation in California and the Juan de Fuca rotations led them to postulate a 5-Myr age for the change. The manner and timing of the change are explored more thoroughly here, and we put the time for the change in motion of the Pacific plate at between 5 and 3.2 Myr, basing the younger limit on the correlation of computed hotspot tracks with Pacific and Nazca hotspot traces. The change may explain several observations on the neighbouring continental and oceanic plate boundaries, including direct adjustments at the Pacific spreading ridges. A likely mechanism for the change is a large clockwise torque caused by acceleration of the sinking slab beneath the Kurile trench, where a fossil spreading ridge is inferred to have been subducted.