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Prasetya, Gegar; Lange, Willem P. de; Healy, Terry R.

doi:10.1023/a:1012297413280

Cited by 73 publications

(23 citation statements)

References 3 publications

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“…With a relatively high slip rate inferred from recent geodetic measurements (40 mm/ year, Socquet et al 2006;Walpersdorf et al 1998) and from geomorphology (upper limit 58 mm/year, Daryono 2018) and clear evidence for Quaternary activity (Watkinson and Hall 2017), the Palu-Koro fault was presumed to pose a threat to the region (Watkinson and Hall 2017). In addition, four tsunamis associated with earthquakes on the Palu-Koro fault have struck the northwest coast of Sulawesi in the past century (1927, 1938, 1968 and 1996) (Pelinovsky et al 1997;Prasetya et al 2001).…”

Section: Tectonic Settingmentioning

confidence: 97%

Coupled, Physics-Based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami

Ulrich

Vater

Madden

et al. 2019

Pure Appl. Geophys.

127

125

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The September 2018, M w 7.5 Sulawesi earthquake occurring on the Palu-Koro strike-slip fault system was followed by an unexpected localized tsunami. We show that direct earthquakeinduced uplift and subsidence could have sourced the observed tsunami within Palu Bay. To this end, we use a physics-based, coupled earthquake-tsunami modeling framework tightly constrained by observations. The model combines rupture dynamics, seismic wave propagation, tsunami propagation and inundation. The earthquake scenario, featuring sustained supershear rupture propagation, matches key observed earthquake characteristics, including the moment magnitude, rupture duration, fault plane solution, teleseismic waveforms and inferred horizontal ground displacements. The remote stress regime reflecting regional transtension applied in the model produces a combination of up to 6 m left-lateral slip and up to 2 m normal slip on the straight fault segment dipping 65 East beneath Palu Bay. The time-dependent, 3D seafloor displacements are translated into bathymetry perturbations with a mean vertical offset of 1.5 m across the submarine fault segment. This sources a tsunami with wave amplitudes and periods that match those measured at the Pantoloan wave gauge and inundation that reproduces observations from field surveys. We conclude that a source related to earthquake displacements is probable and that landsliding may not have been the primary source of the tsunami. These results have important implications for submarine strike-slip fault systems worldwide. Physics-based modeling offers rapid response specifically in tectonic settings that are currently underrepresented in operational tsunami hazard assessment.

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Section: Tectonic Settingmentioning

confidence: 97%

Coupled, Physics-Based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami

Ulrich

Vater

Madden

et al. 2019

Pure Appl. Geophys.

127

125

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“…The most recent tsunami occurred on the evening of 28 September 2018, at 18:02:45, local time (UTC+8), when a moment magnitude (Mw) 7.5 earthquake ruptured a~200-km-long segment of the Palu-Koro strike-slip fault, which bisects Sulawesi and connects with the Minahassa Trench in the north (Bellier et al, 2001;Socquet et al, 2006;Walpersdorf et al, 1998;Watkinson et al, 2012;Watkinson & Hall, 2017;Figure 1a). In this region, three tsunamigenic earthquakes were reported in the past century (1927, 1968, and 1996) with accompanying tsunamis of up to 10 m (Soloviev & Go, 1974), most of them presumably associated with vertical motions caused by either thrust or normal faulting (Prasetya et al, 2001). In contrast, the Palu earthquake was associated with horizontal motion caused by strike-slip faulting.…”

Section: Introductionmentioning

confidence: 99%

Nearly Instantaneous Tsunamis Following the Mw 7.5 2018 Palu Earthquake

Carvajal

Araya‐Cornejo

Sepúlveda

et al. 2019

Geophysical Research Letters

111

166

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The tsunami observations produced by the 2018 magnitude 7.5 Palu strike‐slip earthquake challenged the traditional basis underlying tsunami hazard assessments and early warning systems. We analyzed an extraordinary collection of 38 amateur and closed circuit television videos to show that the Palu tsunamis devastated widely separated coastal areas around Palu Bay within a few minutes after the mainshock and included wave periods shorter than 100 s missed by the local tide station. Although rupture models based on teleseismic and geodetic data predict up to 5‐m tsunami runups, they cannot explain the higher surveyed runups nor the tsunami waveforms reconstructed from video footage, suggesting either these underestimate actual seafloor deformation and/or that non‐tectonic sources were involved. Post‐tsunami coastline surveys combined with video evidence and modeled tsunami travel times suggest that submarine landslides contributed to tsunami generation. The video‐based observations have broad implications for tsunami hazard assessments, early warning systems, and risk‐reduction planning.

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“…(Durrant et al, , 2015 Historical tsunami deposits are not unusual along the coasts of SE Asia (e.g. Rhodes et al, 2011) with the broader Makassar Strait being one of the most tsunamigenic regions in Indonesia (Harris and Major, 2017;Prasetya et al, 2001). For the center of the Makassar Strait, earthquake catalogs report only few significant earthquakes in the last ~100 years (Jones et al, 2014) and this region is considered https://doi.org/10.5194/cp-2019-63 Preprint.…”

Section: Abandoning Conflicting Sea Level Historiesmentioning

confidence: 99%

Holocene and Common Era sea level changes in the Makassar Strait, Indonesia

Bender

Mann

Stocchi

et al. 2019

Preprint

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Abstract. Indonesia is a country composed of several thousand islands, many of them small, low-lying and densely inhabited. These are, in particular, subject to high risk of inundation due to future relative sea level changes. The Spermonde Archipelago, off the coast of Southwest Sulawesi, consists of more than 100 small islands. This study presents a dataset of 24 sea-level index points from fossil microatolls, surveyed on five islands in the Spermonde Archipelago and compares these new results with published data from the same region and with relative sea level predictions from different Glacial Isostatic Adjustment (GIA) models. The newly surveyed fossil microatolls are located around the islands of Tambakulu, Suranti (both ~ 60 km offshore of Makassar city), Bone Batang and Kodingareng Keke (both located in the center of the Archipelago) and Sanrobengi (located ~ 20 km south-southwest of Makassar). Results from the near- and mid-shelf islands indicate that relative sea level between 4 to 6 ka BP was less than one meter above present sea level. The only exception to this pattern is the heavily populated island of Barrang Lompo, where we record a significant subsidence when compared to the other islands. These new results support the conclusions from a previous dataset and are relevant to constrain late Holocene ice melting scenarios. Samples from the two outer islands (Tambakulu and Suranti) yielded ages spanning the Common Era that represent, to our knowledge, the first reported for the entire Southeast Asian region.

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Cited by 73 publications

References 3 publications

Coupled, Physics-Based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami

Coupled, Physics-Based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami

Nearly Instantaneous Tsunamis Following the Mw 7.5 2018 Palu Earthquake

Holocene and Common Era sea level changes in the Makassar Strait, Indonesia

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