Christmas in 2004, a 9.1 magnitude earthquake under the Indian Ocean triggered tsunami waves that killed some 230,000 people across a dozen countries.

The powerful 9.1-magnitude earthquake off the coast of the Indonesian island of Sumatra, triggered a tsunami that killed around 230,000 people across a dozen countries.

Understanding of the Sumatran subduction zone and its hazards has increased since the 2004 Indian Ocean earthquake and tsunami.