Historical Context

We live on a geologically active planet where earthquakes and tsunamis have always occurred, within all oceans and impacting all continents. An early record is from the explosive eruption of the volcanic island of Santorini (Thera) in the Aegean Sea around 1610 BC. It generated a tsunami that swept the shores of nearby islands and contributed to the end of the Minoan culture on the nearby island of Crete.

Understanding when and where tsunamis have happened in the past and the extent of their impacts supports improved planning and preparedness for future tsunamis.

On average, two tsunamis cause damage near their source each year. Tsunamis that cause damage or deaths on distant shores (more than 1,000 kilometers - 620 miles - away) occur about twice per decade. Two of the most noteworthy tsunamis happened in this century and demonstrate the devastating impacts:

Deadliest Tsunami in History

Tsunami damage in Banda Aceh, Indonesia, from the 2004 tsunami.
Tsunami damage in Banda Aceh, Indonesia, from the 2004 tsunami.

On December 26, 2004, an extremely powerful earthquake occurred off the coast of the Indonesian island of Sumatra in the Indian Ocean. This magnitude 9.1 earthquake, the third largest in the world since 1900, generated a tsunami that reached as high as 167 feet (51 meters) and caused flooding up to three miles (five kilometers) inland.

The tsunami, not the earthquake, was responsible for the majority of the impacts, which were observed in 17 countries in Southeastern and Southern Asia and Eastern and Southern Africa. Impacts included approximately 230,000 deaths, the displacement of 1.7 million people, and roughly $13 billion (2017 dollars) in economic losses.

The extent of the losses was partly because of the lack of an official tsunami warning system in the Indian Ocean at the time and limited knowledge about tsunamis.

Take it to the MAX!  2004 Indian Ocean Tsunami

Most Expensive Natural Disaster in History

On March 11, 2011, a magnitude 9.1 earthquake off the east coast of Japan generated a tsunami that caused tremendous devastation locally and was observed throughout the Pacific. The earthquake was the largest ever recorded in Japan. The tsunami reached as high as 127 feet (39 meters) and traveled up to five miles (eight kilometers) inland.

In Japan, the earthquake and tsunami caused more than 18,000 deaths and approximately $243 billion (2017 dollars) in damage. Most of the deaths and damage in Japan were due to the tsunami, which also displaced more than 500,000 people and resulted in a nuclear power plant accident.

The Tsunami Strike: Japan three-part video series explains the science and technology behind the 2011 tsunami
The Tsunami Strike: Japan three-part video series explains the science and technology behind the 2011 tsunami.
Outside Japan, there was very little loss of life. Timely warnings and a large distance from the tsunami's source gave more time for evacuations in coastal communities. However, there was still one death in Papua, Indonesia, and one death in California.

The tsunami also caused approximately $94 million in damage in California and Hawaii and $7 million (2017 dollars) in losses to the fishing industry in Tongoy, Chile.

Historical Tsunamis

The Global Historical Tsunami Database contains information about over 1,200 confirmed tsunamis between 1610 BC and AD 2017. Of these, at least 250 were deadly. Here are the ten deadliest tsunamis on record.

Ten Deadliest Tsunamis from the Global Historical Tsunami Database.
Deaths Year Source Location Ocean Basin Cause*
227,899# 2004 Indonesia, N. Sumatra Indian Earthquake 9.1M
50,000# 1755 Portugal, Lisbon Atlantic Earthquake 8.5M
34,417 1883 Indonesia, Krakatoa Indian Volcano
31,000# 1498 Japan, Enshunada Sea Pacific Earthquake 8.3M
27,122# 1896 Japan, Sanriku Pacific Earthquake 8.3M
25,000 1868 Chile, Northern Pacific Earthquake 8.5M
18,453# 2011 Japan, Honshu Island Pacific Earthquake 9.1M
14,524 1792 Japan, Shimabara Bay, Kyushu Island Pacific Volcano
13,486 1771 Japan, Ryukyu Islands Pacific Earthquake 7.4M
8,000# 1586 Japan, Ise Bay Pacific Earthquake 8.2M

*M=magnitude. Earthquake intensity estimated prior to 1896. 

#May include earthquake deaths.