Natural Disasters

Social media videos can unravel reason behind a giant tsunami

Researchers use 38 such videos of the tsunami to reconstruct Indonesia earthquake

Published: Friday 17 May 2019

Can social media videos unravel the cause behind a giant tsunami that killed thousands of people?  Citizen science proved it could.

They played a big part in solving the mystery behind the tsunami that hit Indonesia in September 2018. The tsunami struck the city of Palu in Sulawesi island last year after an earthquake of 7.5 magnitude and killed more than 4,000 people.

The size of the tidal wave surprised scientists as the tsunami warning system had predicted a much smaller wave. 

Scientists believed that the event was caused by a submarine landslide but had no way to prove it as they had very limited data due to lack of tide gauges and bouys to record in Indonesia. Also, the entry for further investigations were restricted.

A Chilean scientific initiative called ‘Millennium Nucleus The Seismic Cycle Along Subduction Zones’ used amateur videos and surveillance footage instead.

These researchers used 38 such videos of the tsunami to reconstruct the event. They also plotted some of these videos on a map. This allowed the researchers to reconstruct how the tsunami had moved through Palu Bay.

This reconstruction showed that the first tidal wave struck just a few minutes after the shaking and that successive waves came just 1–2 minutes apart. This suggests that the source was close to the shore, which is indicative of a submarine landslide

The study offers a significant piece of evidence supporting the idea that submarine landslides caused the tsunami.

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