Interesting this earthquake struck shortly after a solar eclipse, implying significant spring tide forces were present. The earthquake occurred near dawn, when the sun/moon pair, Indonesia, and the Earth's core formed a right angle to each other, creating tidal tension forces on the crust.
Tidal forces have been linked to the Dec. 26, 2004 Sumatra earthquake. This paper claims there's a significant link between tidal forces and earthquakes in the region (https://doi.org/10.1029/2006GL027074). The authors conclude "The observed relationships suggest that the cyclical crustal flexing, which will be at a maximum at full or new moons, might provide sufficient extra force to a plate-boundary region already on the point of rupture to trigger an earthquake that was ‘waiting to happen’."
Tidal forces have been linked to the Dec. 26, 2004 Sumatra earthquake. This paper claims there's a significant link between tidal forces and earthquakes in the region (https://doi.org/10.1029/2006GL027074). The authors conclude "The observed relationships suggest that the cyclical crustal flexing, which will be at a maximum at full or new moons, might provide sufficient extra force to a plate-boundary region already on the point of rupture to trigger an earthquake that was ‘waiting to happen’."