The 2018 Mw 7.5 Sulawesi Indonesia earthquake: the immediate response of the InaTEWS Warning Centre at BMKG and related operational issues
Abstract
On September 28, 2018, a huge earthquake occurred in Central Sulawesi, Indonesia. This Mw 7.5 earthquake caused severe damage and was followed by a strong tsunami that caused additional damage to the coastal regions around the Palu Bay. As defined by the standard operating procedure for the national tsunami warning, BMKG issued a warning within 5 minutes of the earthquake origin time. Warning messages were sent for Northern Palu City, Western Donggala, Northern Donggala and Western Mamuju with warning levels up to level 2 (wave height of ≥ 0.5 and < 3 meters). After a rapid and detailed analysis of the earthquake parameters including fast moment tensor analysis and inspection of available tide gauge data the warning was terminated in 34 minutes after the origin time, allowing rescue teams to start their operations. Despite the fact that warning messages were timely they were not all successfully received by the stakeholders apparently due to the damaged local infrastructure or because of the tsunami arriving very early in some cases only 3 minutes after the origin time. Additional investigations including field survey have confirmed the underestimation of the impact of the event in the very first minutes, with observed tsunami height reaching 11.3 meters and 500 meters of inundation (peak values). Field observations are also confirming the presence of cascade effects such as several large landslides, soil liquefaction as well as local amplification effects for both the tsunami and the ground shaking. Field observations and tsunami arrival times can not be explained by a single tectonic source with the given mechanism only, but form a consistent picture considering in addition postseismic submarine landslides. This presentation will focus on describing the operations at BMKG in the aftermath of the Sulawesi earthquake, provide some initial results from field surveys as well as describe some issues in the overall tsunami warning chain and future perspectives.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMNH22B..01W
- Keywords:
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- 4313 Extreme events;
- NATURAL HAZARDSDE: 4315 Monitoring;
- forecasting;
- prediction;
- NATURAL HAZARDSDE: 4341 Early warning systems;
- NATURAL HAZARDSDE: 4564 Tsunamis and storm surges;
- OCEANOGRAPHY: PHYSICAL