Post-event Field Survey of 28 September 2018 Sulawesi Earthquake and Tsunami

Abstract

Abstract. An earthquake with a magnitude of MW = 7.5 that occurred in Sulawesi, Indonesia on September 28, 2018, triggered liquefaction and tsunamis that caused severe damage and many casualties. This paper reports the results of a post-tsunami field survey conducted by a team with members from Indonesia and Taiwan that began 13 days after the earthquake. The main purpose of this survey was to measure the runup of tsunami waves and inundation and observe the damage caused by the tsunami. Measurements were made in 18 selected sites, most in Palu Bay. The survey results show that the runup height ranged from 2 to 10 m and that the inundation distance was between 80 and 510 m. The highest runup (10.5 m) was recorded in Tondo, a complex that has many boarding houses near a university. The longest inundation distance (511 m) was found in Layana, a marketplace. The arrival times of the tsunami waves were quite short and different for each site, typically about 3–8 minutes from the time of the earthquake event. The characteristics of the damage to buildings, facilities, and structures are also summarized. Several indicators of underwater landslides are described. The survey results can be used for the calibration and validation of hydrodynamic models for tsunamis. They can also be used for regional reconstruction, mitigation, planning, and development.

Cascading Geological Hazards and Risks of the 2018 Sulawesi Indonesia Earthquake and Sensitivity Analysis of Tsunami Inundation Simulations

“…Along the coastal areas of Palu Bay, damaging tsunami waves arrived, destroyed buildings that were located within inundated areas, and caused fatalities (Sahadewa et al, 2019;Widiyanto et al, 2019). It is important to examine tsunami wave profiles and tsunami inundation extent of the 2018 Sulawesi earthquake via tsunami simulation.…”

“…In the past, the Palu-Koro Fault zone caused several deadly earthquake disasters (Pelinovsky et al, 1997;Thein et al, 2014;Cipta et al, 2016). The capital city Palu of Central Sulawesi Province, which is home to more than 375,000 people, was devastated by cascading geological hazards (Sahadewa et al, 2019;Widiyanto et al, 2019) -strong shaking due to the mainshock, triggered tsunamis, and large-scale mass movements. As of February 2019, the numbers of deaths/missing and injured exceeded 4,340 and 4,438, respectively.…”

SAR and Optical Data Comparison for Detecting Co-Seismic Slip and Induced Phenomena during the 2018 Mw 7.5 Sulawesi Earthquake

“…In particular, after the seismic event, two big landslides have been observed close to the airport and on the eastern outskirts of Palu city [27,28]. Moreover, the M w 7.5 seismic event and the induced phenomena largely impacted on Palu bay provoking a coastline retreat and completely destroying several buildings and the Palu IV bridge [29,30,31] (Figure 7).…”

Runup, Inundation, and Sediment Characteristics of 22 December 2018 Indonesia Sunda Strait Tsunami

“…The tracks were in the form of debris, fallen trees, plants 15 that change color, and damage to buildings. The observed damage to buildings and structures was caused by the tsunami because there were no other causes, such as the earthquakes and liquefaction in the 2018 Sulawesi tsunami (Widiyanto et al, 2019). In addition, information regarding inundation limits and highest runup was also obtained from eyewitnesses.…”