The 1833 Sumatra earthquake occurred on November 25 at about 22:00 local time, with an estimated magnitude in the range of 8.8–9.2 Mw .

Waves have also been reported to reach northern Australia, the Bay of Bengal and Thailand, although in small intensity.

[2] The rupture extent and the magnitude of this earthquake has been determined using the effect of relative sea level changes on coral microatolls from a group of small islands along the outer arc ridge that runs parallel the coast of Sumatra, the Mentawai islands.

These microatolls, named for their resemblance to island atolls, can be used to provide a record of sea level change.

[2] Modelling of the tsunami suggests that most of the energy would have been radiated out into the Indian Ocean, sparing most coastal population centres outside Sumatra itself.