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Tsunamis are usually a series of successive waves. Tsunamis travel at approximately 800km/h – around the speed of a passenger jet plane. After the devastating tsunami in the Indian Ocean on Boxing Day, 2004, there have been vast improvements in early warning systems in places more prone to these hazards.

In this instance, tsunami warnings were broadcasted over most of the Pacific including nearby Japan where 1.9 million people were ordered to evacuate and find higher land.

The early tsunami warnings meant that most people had enough time to get to safety. However, even at this speed, the waves can take hours to arrive and therefore there were mixed responses to the threat of the wave. The time it took for the waves to travel across the Pacific dissipated their strength and therefore most of the tsunami warnings were downgraded.

Prediction versus reality

Tsunami warning systems across the Pacific worked well, giving people enough time to evacuate if a tsunami had occurred. In the end, though, the wave energy had weakened before it posed any serious threat to coastal communities meaning that most warnings were downgraded.

This is very different from the Boxing Day (2004) and the Tohoku (2011) tsunamis, both of which were caused by similar earthquakes and yet caused widespread destruction and significant loss of life.

This highlights how difficult it can be to predict these events accurately and respond in the right way. To protect lives, authorities are choosing to be cautious, issuing early warnings and then reducing the threat level as more reliable data becomes available. Over time, as more events are recorded and analysed, tsunami models are likely to improve, helping to make future predictions more accurate.

Further reading

• Russia earthquake: Magnitude 8.8 megaquake hits Kamchatka, generating tsunamis across the Pacific. Live Science July 30, 2025.
• BBC, 30 July 2025.
• . The Conversation, 30 July 2025.
• The Conversation, 31 July 2025.