Science Behind the 2018 Sept Sulawesi Tsunami - Geonews Ep6

This Geonews video is about the tsunami that struck Indonesia, on the Island of Sulawesi in Indonesia on Friday, September 28th. This earthquake and tsunami is in the news because these claimed many lives and disrupted the lives of many others. The origin of this tsunami was a bit unusual and worth learning more about.

Tsunamis happen when seafloor moves up or down suddenly, displacing the overlying seawater. This generally happens when a big earthquake occurs at shallow depths in a subduction zone. A subduction zone is where one tectonic plate slides beneath another. A monster earthquake shallow in the subduction zone is what caused the 2004 Indian Ocean tsunami and the 2011 tsunami in North East Japan. What makes the Sulawesi tsunami unique is that a subduction zone was not responsible. The earthquake that caused this tsunami did occur at a plate boundary, between the Sunda and Molucca Sea plates, but it happened on a strike-slip fault. Strike-slip faults are where two plates move past one another rather than over and under, as happens in subduction zones. Strike-slip faulting is associated with devastating earthquakes like the San Francisco Earthquake of 1906, caused by movement along the San Andreas Fault. However, strike-slip faults do not normally cause tsunamis. In order for the Pula-Koro strike-slip fault to have caused the Sulawesi tsunami, there must have been some vertical displacement of the seafloor along the fault, or the earthquake caused a massive underwater landslide.

The city of Palu was devastated due to its unfortunate location at the back of a large, narrow bay that opened towards the earthquake epicenter. As the tsunami traveled up the bay, displaced water was focused directly towards Palu.Palu caught the worst from the tsunami and also suffered because it was so close to the earthquake - less than 50 miles south of the epicenter.

I hope you learned something useful from this tragedy. If we better understand what happened at Sulawesi, we are better able to prepare for similar future disasters. If you want to help the people devastated by this earthquake and tsunami, CNN has a great website here where you can donate to different humanitarian efforts, working on disaster relief.

Credits & Sources

GOOGLE EARTH PRO

World Map from Geology.com

TODAY (NEWS)

How tsunamis work - Alex Gendler (Ted-Ed)

Tom Campion’s YouTube Video (How Tsunami is Formed)

UTD GTML - Plate Tectonics Basics 1

Gloster.com – 2004 Indian Ocean Tsunami

CBS - Japan earthquake, tsunami kill hundreds

ILStv.com - 1906 San Francisco Earthquake

Wolfram - Simulating Strike-Slip Fault (YouTube)

ZMEScience - www.zmescience.com

Psydent - Why the San Andreas is not completely a strike-slip fault (YouTube)

ABC News - Indonesia tsunami: An underwater landslide likely caused the widespread destruction in Sulawesi

WSJ - ‘Buried in Mud’: Death Hangs Over Palu After Indonesia Quake, Tsunami (Highly Recommended)

South China Morning Post

9News Sydney

https://www.9news.com.au/content/2018/10/01/18/32/death-toll-from-indonesian-earthquake-and-tsunami-expected-to-rise#8

https://www.cnn.com/2018/09/30/world/iyw-aid-indonesia-earthquake-and-tsunami-victims/index.html

CNN ‘ Aid Indonesia earthquake and tsunami victims ‘

https://www.theguardian.com/world/2018/oct/04/sulawesi-tsunami-indonesia-battles-fake-news-as-hoaxers-spread-panic

https://www.digitalglobe.com/

https://www.youtube.com/watch?v=KLCEtqANQew