28 September 2018, Mw7.5, Palu, Indonesia Tsunami

UPDATE - 5 December 2018

For more information, visit the 28 September 2018 event, and ITST-Palu survey pages.

The 28 September 2018 magnitude 7.5 Palu, Indonesia earthquake (0.178°S, 119.840°E, depth 13 km) occurred at 1002 UTC.  The major earthquake triggered catastrophic liquefaction, landslides, and a near-field tsunami that resulted in direct damage, impact, economic loss, and loss of life.

As of 26 October 2018 according to the One ASEAN One Response (AHA) Centre (Sit Update 15), the earthquake and subsequent tsunami that had hit Palu and Donggala in Central Sulawesi Indonesia, Friday 28 September 2018, has killed 2081 people. 1309 people are missing or buried (in liquefaction area), 4,438 with major injuries, 206,494 displaced, and 68,451 houses damaged.  The three most affected areas were Donggala, Palu City, Sigi, and Parigi Moutong.

Click to view photos superimposed on aerial imagery taken after the event.Click to view before and after high-resolution satellite imagery of the impacted area (Digital Globe and Map Action).

The BMKG reported 591 aftershocks, with 28 strong enough to be felt, h through 24 October 2018 (0900 local) A recently retrieved marigram from the Pantoloan - Sulteng tide gauge shows a 3.8 m trough-to-peak tsunami that arrived six (6) minutes after the earthquake’s origin.  Several analyses based on pictures, post disaster information, and video clips suggest the first tsunami wave hit the Palu beach area within 5 minutes after the earthquake. Preliminary field surveys conducted by the BMKG and led by Tohoku Univ/Indonesia Ministry of Environment and Forestry/Chuo Univ report an eyewitness height of up to 11.3 m in Palu and 1.57-10 m on the west and east sides of the bay.

Between October 18 and November 30, 2018, 6 International Tsunami Survey Teams (ITST) comprised of 70 international and Indonesia scientists collaborated to conduct surveys as part of the UNESCO-facilitated ITST-Palu.  They collected inundation, runup, and flow depth data, earthuqake and tsunami impacts to engineered structures, drone imagery and bathymetric surveys, and eyewitness accounts of the tsunami wave arrival and impacts.  The data will answer questions on how and why the deadly earthquake and tsunami occurred, what its impact was, and how we can better reduce future losses for similar events.

Preliminary research results will be presented at the 2018 Fall American Geophysical Meeting (AGU) late-breaking session The 2018 Mw 7.5 Sulawesi Indonesia earthquake: tsunamigenic potential of strike slip faults on 11 December 2018 in Washington, D.C.  Click to download session oral and poster presentations.

Top: Co-seismic coastal subsidence, Donggala city  Bottom: Liquefaction effects, Palu city. 
(photos:  ITIC, US Embassy Jakarta)