A powerful and shallow earthquake of magnitude 7.9 has struck off the west coast of the Indonesian island of Sumatra today.A tsunami alert has been issued as far as Australia’s western coast – with warnings that deaths are ‘inevitable’.Footage purporting to capture the moment the quake rocked Indonesia is circulating online – but it is actually fake.The video, which has been picked up by some national news sites, shows the ground trembling inside a bank.Men and women can be seen running for for their lives, while debris flies off the building’s ceilings and walls.But despite initial appearances, the footage was actually filmed in China in 2013.Marjina, a resident of Sikakap in the Mentawai islands, about 450 miles from the epicentre, said the quake was felt weakly there, but the tsunami warning caused panic among villagers, who ran to higher ground. -