The humanitarian response to the 2004 Indian Ocean earthquake was prompted by one of the worst natural disasters of modern times. On 26 December 2004, the earthquake, which struck off the northwest coast of the Indonesian island of Sumatra, generated a tsunami that wreaked havoc along much of the rim of the Indian Ocean. Particularly hard-hit were the countries of Indonesia, Sri Lanka, and Thailand. About 230,000 people were killed, tens of thousands more were injured, and 100 million became homeless and displaced.