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The 2018 Sulawesi Earthquake and Tsunami: What happened and how to mitigate the impact in the future

Vasily V. Titov, Celia Lowe, and Harold Tobin

November 2, 2018

UW PhD students Dimas Romadhon (Anthropology) and Abdullah Habibi (Aquatic and Fishery Sciences) organized an event that investigated the geophysical causes of the September 28th earthquake in Central Sulawesi’s

Vasily V. Titov, Celia Lowe, and Harold Tobin

Donggala Regency and the ensuing tsunami.  Held on campus in the Pacific Northwest Seismological Netowrk (PNSN) laboratory, speakers included Dr. Harold Tobin, PNSN’s new Director; Dr. Vasily Titov, Project Leader for NOAA’s Center for Tsunami Research; and SEAC’s Director, Dr. Celia Lowe.  The discussion was recorded as both a livestream feed and for future broadcast to audiences in Indonesia as part of an initiative by Nahdlatul Ulama which will distribute it to government agencies and educational institutions. Similar seminars had been held in Japan and Netherlands within the past few weeks.

Dr. Tobin began the discussion about the earthquake on the Palu-Koro fault, thought to be a strike-slip fault, which registered 7.5 on the Richter scale and was followed by many aftershocks.  He noted that the fault ran directly under the center of Palu city, one reason for the severity of the damage there.  Another widely-reported cause of destruction were the massive landslides caused by liquefaction of the soils, a risk that had been documented many years before the quake struck.

More tragically, the disaster did not end when the shaking stopped.  According to Dr. Titov, about 5-10 minutes later the first of what are believed to have been three tsunami waves crashed ashore.  For scientists this was unexpected because strike-slip faults are not typically associated with tsunami generation and it usually requires quakes of even larger magnitude to trigger one.

The tsunami originated in Palu Bay.  One theory to explain its formation is that the narrow bay’s coastline acted as a wave generator, like the sides of a bathtub when water in the tub is agitated.  However, Dr. Titov also noted that a pilot, who had lifted off seconds before the earthquake occurred, took photos from the cockpit of what appears to be the earliest stages of wave generation.  These photos, the first of their kind according to Dr. Titov, suggest that the waves may have been caused when landslides plummeted into the bay. Scientific analysis is ongoing, but both Dr. Tobin and Dr. Titov agree that complex mechanisms were at work which amplified the damage to manmade structures and natural features and greatly exacerbated the loss of life.  Adverse effects on the population will continue to mount because of the destruction of farmland by massive landslides.

Dr. Lowe’s presentation concerned the importance of good governance both to mitigate the scale of ecological disasters and to provide an effective response when they occur.  She reminded the audience that Seattle faces a similar risk and that we should recognize the commonality between residents here and in Donggala Regency.  The full text of her presentation is transcribed below:


Sulawesi, which was known in colonial times as the Celebes, is the world’s 11th largest island. It is an island consisting only of peninsulas, said to take the shape of an orchid, with petals reaching out in four directions.

I conducted research in Sulawesi on scientists doing biodiversity conservation between 1993 and 2000 in a tiny archipelago to the east of Palu called the Togean Islands. This region of Sulawesi sits at the intersection of three lines:

Wallace’s line (of which there are several variants) divides the eastern and western halves of the Indonesian archipelago and demarcates a separation between Asiatic placental mammals and the Australian marsupial forms. Now the region around Sulawesi is called Wallacea and is thought of more as a zone of transition than a fixed line. It is also a zone of extremely high marine biodiversity.

The equator also goes right through this site. The equator demarcates global north and global south. For me when I was writing about Sulawesi, the equator brought attention to the falsity of those inherent divisions that are supposed to exist between “North” and “South,” or in older terms “East” and “West.” There were many Indonesians doing interesting science in Sulawesi when I was there, and yet they were sometimes excluded from international scientific projects. The equator signifies an invisible line of incommensurability which those from both the Global North and Global South have invested in in particular ways.

The third line is a thread of rattan that connected Central Sulawesi to South Sulawesi and to Ternate in a local myth. These three locations were thought of as siblings by the Togean man who related this myth to me. Central Sulawesi was bound to the Sultanates in Bone and Ternate through biological, political, and mystical forces. This story signifies how our scientific narratives of biodiversity or earth science form a thin layer upon much older histories in Sulawesi. Sulawesi is a location of strong mystical powers, histories of pirating and slaving, sea peoples and forest peoples who know their surroundings intimately, the sea cucumber trade that has linked Sulawesi to China for a millennium, 19th century natural history, many layers of colonialism and colonization, and more recent violence between Christians and Muslims.

Now we learn there is a fourth line, the Palu Koro fault. The Palu disaster is a mix of human and natural forces. Of course the earthquake and tsunami were not anthropogenic in any sense, but a recent New York Times article, “Nature Cursed Indonesia, But it Took Neglect to Make a Disaster,” (Hannah Beech and Muktita Suhartono, Oct 16, 2018), describes how the toll to human life and infrastructure indeed has a human source.  Building unreinforced buildings on top of the fault, or building government subsidized housing in a sago swamp were both human errors. So was ignoring the scientific information available to city administrators and the Indonesian government about fault line and zones of liquefaction. And as the Times authors write, “soldiers could be seen helping themselves to some of the supplies trucked in by aid groups or standing by as residents swarmed the vehicles.” In rapidly urbanizing Indonesia, there seems to be no room for building codes or for the tsunami early warning system that was not operational.

We should not think of this as an Indonesian problem, however. If we think about the location of the city of Seattle on its own fault line, we can be concerned about our downtown built upon soft ground, our own building codes which are not the rigorous codes of Japan or Argentina, or the lack of earthquake insurance for most of our homes. So as we speak of Sulawesi today, we should think not of hemispheric divides, but of the threads that bind us to our fellow humans in Indonesia who have only experienced the common intersection between poor governance, human avarice, and the Richter scale somewhat before we most certainly will.



Full recording of the discussion can be viewed here.