A powerful undersea earthquake that struck off the coast of Sumatra island, Indonesia, set off the Indian Ocean tsunami, also known as the Christmas or Boxing Day tsunami, on Sunday morning, Dec. 26, Then, in succession, tsunami waves rolled over coastlines in Thailand.
The humanitarian response to the Indian Ocean earthquake of a magnitude of was prompted by one of the worst natural disasters of modern times. On 26 December , the earthquake, which struck off the northwest coast of the Indonesian island of Sumatra, generated a tsunami that wreaked . Tony Blair, the UK prime minister, also expressed concern that tsunami aid.
The aid response to the Indian Ocean tsunami was unprecedented for a natural disaster, with a colossal $bn donated to a central UN.