Longest earthquake
- Who
- Unknown
- What
- 500–600 second(s)
- Where
- United Kingdom
- When
- 26 December 2004
The Sumatra-Andaman Islands earthquake in the Indian Ocean, on 26 December 2004, was the longest-lasting ever recorded. Its duration, monitored by seismometers all over the world, was measured at between 500 and 600 seconds. It had an earthquake magnitude of between 9.1 and 9.3. These results were announced in the journal Science in May 2005.