Why the Indonesia earthquakes had minimal impact
A tsunami watch declared after two major earthquakes off the coast of Indonesia's Aceh province has now been cancelled, the Pacific Tsunami Warning Center says.
Two hours after the quakes - one with a magnitude of 8.6, the other measuring 8.3 - the centre says "the threat has diminished or is over for most areas".
The alerts caused panic as people fled buildings and made for high ground.
John McCloskey, a geophysics professor at the University of Ulster, explained why the impact had been minimal.
11 Apr 2012