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 is VII (Very strong). Ten are killed

The 2012 Indian Ocean earthquakes were magnitude 8.6 and 8.2 M_w  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 large intraplate earthquakes and the largest strike-slip earthquake ever recorded.