All 22 of the early-warning buoys Indonesia that were deployed after the 2004 tsunami disaster were inoperable when a massive undersea earthquake struck off the country's coast on Wednesday, a national disaster mitigation agency official said.

The magnitude-7.8 quake did not trigger a tsunami, and there were no deaths and no major damage, but it did expose gaps in the systems put in place to prevent a disaster similar to the Indian Ocean quake that killed more than 200,000 people 11 years ago.

In addition to the malfunctioning of buoys designed to warn of massive waves, authorities said there were not enough evacuation routes or shelters in Padang, a Sumatra island port city of around 1 million people that felt the quake.