The 2005 Nias–Simeulue earthquake occurred on 28 March off the west coast of northern Sumatra, Indonesia. At least 915 people were killed, mostly on the island of Nias. The event caused panic in the region, which had already been devastated by the massive tsunami triggered by the 2004 Indian Ocean earthquake, but this earthquake generated a relatively small tsunami that caused limited damage. It was the third most powerful earthquake since 1965 in Indonesia.

Gunungsitoli is a city located in North Sumatra province, Indonesia, on the Indian Ocean island of Nias, west of Sumatra. Gunungsitoli is the island's only city and is the main hub for the island and surrounding smaller islands. Located on the north-eastern side of Nias island, the city was historically a series of fortifications made by the Dutch colonial administration in the 1600s to defend against frequent raids from Nias tribes, especially those from southern parts of the island. Until 1914, it was the only part of the island that was effectively controlled by the Dutch.