A pair of great earthquakes occur in the Wharton Basin west of Sumatra in Indonesia. The maximum Mercalli intensity of this strike-slip doublet earthquake was VII (Very strong). Ten were killed, twelve were injured, and a non-destructive tsunami was observed on the island of Nias.
The 2012 Indian Ocean earthquakes were magnitude 8.6 and 8.2 Mw undersea earthquakes that struck near the Indonesian province of Aceh on 11 April at 15:38 local time. Initially, authorities feared that the initial earthquake would cause a tsunami and warnings were issued across the Indian Ocean; however, these warnings were subsequently cancelled. These were unusually strong intraplate earthquakes and the largest strike-slip earthquake ever recorded.