19 October 2018
Landslide tsunamis from the Sulawesi earthquake
Our understanding of the Sulawesi earthquake continues to improve as more information becomes available. This has shown Twitter at its very best, with a range of people bringing different expertise, and techniques to bear on the problem of what has proven to be a very complex event. I would like to recommend in particular Austin Elliott, John O’Leary, Xiaohua Xu, Eric Fielding and (most impressive of all) Sotiris Valkaniotis, all of whom have been very proactive in interpreting and synthesising the data, and making the information available online.
New videos continue to appear on Youtube. One is particularly interesting, taken from a boat located just offshore when the tsunami struck:-
There is so much in this video that it is hard to know where to start. The video opens with a view roughly southwards (corrected from earlier version) up the bay, showing an enormous landslide generated displacement wave from the western side of the bay:-
The view then switches to the east side, where another landslide tsunami has been generated:-
Incidentally, as the camera pans from one to the other, a third wave, generated from the eastern side of the bay, can also be seen. Meanwhile, in the background the multiple dust plumes generated by landslides in the hills can be seen:-
On Twitter, Austin Elliott managed to tie down the location of the boat to -0.8303, 119.8133, and John O’Leary confirmed that there was a landslide at that point.
This video aligns nicely with the remarkable video taken by a pilot of an aircraft that had just left Palu airport when the earthquake struck. This video also shows the generation of landslide tsunamis by the Sulawesi earthquake:-
We have never had such a detailed and nuanced view of the way that coastal landslides generate local tsunamis during an earthquake.