The tsunami warning remains in effect and a 17cm-tall wave is heading for Aceh, Indonesia, according to the Indonesia-Pacific tsunami warning centre.
Dr David Rothery, who runs the Open University’s Volcanoes, Earthquakes and Tsunamis course, says:
A tsunami detection buoy (a DART station) in the Bay of Bengal detected a wave with an amplitude of 30 cm in deep water, which has the potential to become several times higher as it approaches the shore.
Today’s quake was probably about ten times less energetic than the M9.1 quake that caused the 26 Dec 2004 Indian Ocean tsunami.
In addition, the nature of the quake, on the bending Indian ocean floor as it approaches the Sunda Trench (rather than a megathrust quake in the trench itself) may mean that the displacement of water to trigger the tsunami is less bad; the motion of the sea bed is different to that which occurred in 2004.
– Dr David Rothery, Open University tsunami expert