Evidence-Calibrated Numerical Model of December 22, 2018, Anak Krakatau Flank Collapse and Tsunami

Omira, Rachid; Ramalho, Inês

doi:10.1007/s00024-020-02532-x

Cited by 16 publications

(7 citation statements)

References 35 publications

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“…Although a superficially similar edifice, the pattern of disintegration at Anak Krakatau is in strong contrast to Ritter, suggesting that the bulk properties, fragmentation and pre-collapse pattern of deformation preconditioning failure, may not be easily predictable. Nevertheless, for Anak Krakatau, assuming either a simple dense Newtonian fluid or homogeneous granular slide rheology, numerical models can reproduce, the near- and far-field tsunami observations from our estimated failure volume 14 , 24 – 27 , 33 – 37 , 45 , 46 . While translational subaerial landslides are reported at other volcanic island sites, the detailed pre- and post-event surveys at Anak Krakatau and direct monitoring of the tsunami makes this an important benchmark event.…”

Section: Discussionmentioning

confidence: 77%

Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018

et al. 2021

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As demonstrated at Anak Krakatau on December 22nd, 2018, tsunamis generated by volcanic flank collapse are incompletely understood and can be devastating. Here, we present the first high-resolution characterisation of both subaerial and submarine components of the collapse. Combined Synthetic Aperture Radar data and aerial photographs reveal an extensive subaerial failure that bounds pre-event deformation and volcanic products. To the southwest of the volcano, bathymetric and seismic reflection data reveal a blocky landslide deposit (0.214 ± 0.036 km3) emplaced over 1.5 km into the adjacent basin. Our findings are consistent with en-masse lateral collapse with a volume ≥0.175 km3, resolving several ambiguities in previous reconstructions. Post-collapse eruptions produced an additional ~0.3 km3 of tephra, burying the scar and landslide deposit. The event provides a model for lateral collapse scenarios at other arc-volcanic islands showing that rapid island growth can lead to large-scale failure and that even faster rebuilding can obscure pre-existing collapse.

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Section: Discussionmentioning

confidence: 77%

Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018

et al. 2021

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“…The fault mechanism did not suggest that the tsunami would be so destructive. The wave rapidly reached Palu (∼ 8 min), implying that its source was inside or near the bay (Muhari et al, 2018;Omira et al, 2019). Its short wave period (∼ 3.5 min) also indicates a non-seismic source (i.e., landslide).…”

Section: Introductionmentioning

confidence: 98%

“…The subaerial and submarine landslide volume is still being investigated and ranges between 0.10 and 0.30 km 3 according to recent studies (Dogan et al, 2021;Grilli et al, 2019;Omira and Ramalho, 2020;Paris et al, 2020;Williams et al, 2019). Almost 2 months before this event, an unexpected tsunami struck Palu Bay, on Sulawesi Island, claiming 2000 lives and considerable loss to property (Association of Southeast Asian Nations (ASEAN)-Coordinating Centre for Humanitarian Assistance on disaster, 2018; Omira et al, 2019). The Sulawesi earthquake (M w = 7.5) occurred near the Palu-Koro strike-slip fault, 50 km northwest of Palu Bay (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Some studies suggested that submarine landslides are responsible for the main tsunami. Moreover, a dozen coastal landslides were reported during field surveys and likely contributed to amplify tsunami waves (Arikawa et al, 2018;Muhari et al, 2018;Omira et al, 2019;Pakoksung et al, 2019). However, according to Ulrich et al (2019), those subaerial and submarine landslides may not be the only tsunami source as the Sulawesi earthquake rupture may have also induced a large portion of the tsunami waves.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of building fragility curves for seismic and non-seismic tsunamis: case studies of the 2018 Sunda Strait, 2018 Sulawesi–Palu, and 2004 Indian Ocean tsunamis

Lahcene

Ιωάννου

Suppasri

et al. 2021

Nat. Hazards Earth Syst. Sci.

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Abstract. Indonesia has experienced several tsunamis triggered by seismic and non-seismic (i.e., landslides) sources. These events damaged or destroyed coastal buildings and infrastructure and caused considerable loss of life. Based on the Global Earthquake Model (GEM) guidelines, this study assesses the empirical tsunami fragility to the buildings inventory of the 2018 Sunda Strait, 2018 Sulawesi–Palu, and 2004 Indian Ocean (Khao Lak–Phuket, Thailand) tsunamis. Fragility curves represent the impact of tsunami characteristics on structural components and express the likelihood of a structure reaching or exceeding a damage state in response to a tsunami intensity measure. The Sunda Strait and Sulawesi–Palu tsunamis are uncommon events still poorly understood compared to the Indian Ocean tsunami (IOT), and their post-tsunami databases include only flow depth values. Using the TUNAMI two-layer model, we thus reproduce the flow depth, the flow velocity, and the hydrodynamic force of these two tsunamis for the first time. The flow depth is found to be the best descriptor of tsunami damage for both events. Accordingly, the building fragility curves for complete damage reveal that (i) in Khao Lak–Phuket, the buildings affected by the IOT sustained more damage than the Sunda Strait tsunami, characterized by shorter wave periods, and (ii) the buildings performed better in Khao Lak–Phuket than in Banda Aceh (Indonesia). Although the IOT affected both locations, ground motions were recorded in the city of Banda Aceh, and buildings could have been seismically damaged prior to the tsunami's arrival, and (iii) the buildings of Palu City exposed to the Sulawesi–Palu tsunami were more susceptible to complete damage than the ones affected by the IOT, in Banda Aceh, between 0 and 2 m flow depth. Similar to the Banda Aceh case, the Sulawesi–Palu tsunami load may not be the only cause of structural destruction. The buildings' susceptibility to tsunami damage in the waterfront of Palu City could have been enhanced by liquefaction events triggered by the 2018 Sulawesi earthquake.

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“…Anak Krakatau volcano emerged to the surface on December 29, 1927, from 180 meters underwater [1] and has erupted many times. On December 22, 2018, a massive eruption generated the flank collapse of Anak Krakatau volcano, led to a destructive tsunami that hit the coastal areas along the shoreline of Sunda Strait, resulting in 437 casualties, 31.943 injuries, 10 still missing, and over 16.000 people displaced [5][6] [7]. The eruption activity was high since June 2018 and continued until December 2018.…”

Section: Introductionmentioning

confidence: 99%

Identification of lava presence on Anak Krakatau volcano using normalized hotspot index before a flank collapse in 2018

Ramadhani,

Jumadi

2024

IOP Conf. Ser.: Earth Environ. Sci.

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On December 22, 2018, a catastrophic tsunami struck Anyer Beach in Banten, Indonesia, resulting in numerous casualties and extensive damage to the region. A flank collapse in the southwest sector of Anak Krakatau primarily triggered this tsunami. Intense eruptions and subsequent lava discharges precipitated this collapse. Indonesia’s Vulcanology Geological Hazard Mitigation Center has reported heightened activity at this location since June 2018. Comprehensive field studies, bolstered by remote sensing data, have been pivotal in enhancing our understanding of the behavior of Anak Krakatau over recent years. This research strives to pinpoint lava’s presence in Anak Krakatau during its eruptions. The methodologies employed include the Normalized Hotspot Index (NHI) transformation index combined with the SWIR-1 and SWIR-2 channels of the Landsat 8 OLI imagery. The goal is to elucidate the intense lava flow patterns associated with the flank collapse. Our findings indicate that the NHI can detect elevated lava flow activity in Anak Krakatau. Within the 13 datasets from 2018, lava flow was discerned on seven occasions between July 29 and December 20, predominantly directed towards the southwest sector of the volcano.

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Evidence-Calibrated Numerical Model of December 22, 2018, Anak Krakatau Flank Collapse and Tsunami

Cited by 16 publications

References 35 publications

Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018

Submarine landslide megablocks show half of Anak Krakatau island failed on December 22nd, 2018

Characteristics of building fragility curves for seismic and non-seismic tsunamis: case studies of the 2018 Sunda Strait, 2018 Sulawesi–Palu, and 2004 Indian Ocean tsunamis

Identification of lava presence on Anak Krakatau volcano using normalized hotspot index before a flank collapse in 2018

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