2018 Sulawesi earthquake

2018 Sulawesi earthquake
Name	2018 Sulawesi earthquake
Date	2018-09-28
Time	17:02:44 UTC
Magnitude	7.5 M_w
Depth	10 km
Location	Sulawesi, Indonesia
Type	Strike-slip
Countries affected	Indonesia
Casualties	~4,300 dead, ~10,700 injured, ~680 missing

2018 Sulawesi earthquake The 2018 Sulawesi earthquake struck near the city of Palu on the Indonesian island of Sulawesi on 28 September 2018, producing a powerful seismic event and a disastrous tsunami that struck coastal communities, notably Palu and Donggala. The event triggered landslides, liquefaction, and widespread infrastructure collapse, provoking a national and international emergency response involving Indonesian agencies, foreign militaries, and humanitarian organizations. Scientific analyses engaged seismologists, geologists, and oceanographers from institutions worldwide to study fault mechanics, tsunami generation, and hazard mitigation.

Background and tectonic setting

Sulawesi lies within the complex convergent margin between the Australian Plate, Pacific Plate, and fragments of the Eurasian Plate, including the Sunda Plate and the Molucca Sea Plate. The island is crossed by major structures such as the Palukoro Fault, the Palu-Koro Fault, and the Mamuju Fault Zone, which accommodate strike-slip and thrust motion associated with the Wallace Line biogeographic boundary and regional terrane accretion. Historical seismicity includes events studied by the United States Geological Survey, the British Geological Survey, and the Geological Agency of Indonesia (Badan Geologi), and investigations referenced work from the Indonesia Tsunami Early Warning System and researchers affiliated with LIPI and international centers like the IRIS Consortium and GFZ German Research Centre for Geosciences.

Earthquake details

The earthquake was recorded by the United States Geological Survey (USGS), the BMKG (Badan Meteorologi, Klimatologi, dan Geofisika), and global networks including NEIC and the European-Mediterranean Seismological Centre. Moment magnitude estimates centered on 7.5 M_w with focal depths reported near 10 km and faulting interpreted as nearly pure strike-slip on the Palu-Koro Fault. Geodetic data from Global Positioning System stations and InSAR imagery from the European Space Agency satellites, including Sentinel-1, documented coseismic displacement, while paleoseismology work by teams from University of Tokyo, Caltech, University of Cambridge, and University of Colorado Boulder examined slip rates and recurrence intervals. The sequence included numerous aftershocks catalogued by Incorporated Research Institutions for Seismology and modeled by researchers at Massachusetts Institute of Technology and National Taiwan University.

Tsunami and secondary hazards

The tsunami that inundated the Palu Bay coastline was recorded by tide gauges maintained by NOAA, BMKG, and private observatories; maximum run-up heights varied locally due to bay geometry, with amplification described in studies from Scripps Institution of Oceanography and the University of Tokyo's Earthquake Research Institute. Secondary hazards included large-scale liquefaction documented in residential districts, landslides investigated by teams from UNICEF and International Red Cross and Red Crescent Movement, and coastal subsidence measured by Institute of Technology Bandung researchers. Debate among proponents from NOAA Pacific Marine Environmental Laboratory and critics in the Royal Society centered on whether submarine landslides, rather than sole tectonic displacement, largely generated the tsunami, a hypothesis researched by groups at AIST and University of Washington.

Human impact and casualties

Casualty and displacement figures were reported by the Indonesian National Board for Disaster Management (BNPB), the Ministry of Health (Indonesia), and international agencies such as UN OCHA and WHO. Estimates converged on roughly 4,300 fatalities, over 10,000 injuries, and hundreds reported missing, with about 200,000 displaced in evacuation centers run by Indonesian Red Cross (PMI), Palang Merah Indonesia, and municipal authorities of Palu, Donggala, Sigi Regency, and Parigi Moutong Regency. Survivors received assistance from USAID, the European Commission's Civil Protection and Humanitarian Aid Operations, JICA, and bilateral aid from countries including Australia, Japan, United States, China, and Singapore.

Damage and infrastructure effects

Infrastructure damage impacted transportation, utilities, and cultural heritage. Palu's Muatara Bridge and portions of the Jalan Trans-Sulawesi network were damaged, while the Sultan Hasanuddin International Airport and regional ports experienced disruptions reported by Angkasa Pura I operators. Power outages affected grids managed by Perusahaan Listrik Negara (PLN), communications networks operated by Telkomsel and Indosat Ooredoo suffered outages, and hospitals such as Undata Hospital and facilities overseen by the Ministry of Health (Indonesia) functioned under strain. Damage to schools and religious sites prompted assessments by UNESCO, and insurance analyses were conducted by firms including Munich Re and Swiss Re.

Emergency response and relief efforts

The initial response was coordinated by BNPB, with rapid deployments from the Indonesian National Armed Forces (TNI) and National Police (Polri), alongside international search and rescue teams accredited under the International Search and Rescue Advisory Group (INSARAG). Humanitarian clusters coordinated by UN OCHA involved WFP, UNICEF, IOM, and WHO, while NGOs such as Red Cross Society, Médecins Sans Frontières, Save the Children, and Mercy Corps delivered medical aid, shelter, and water-sanitation services. Logistical support included airlifts by the Royal Australian Air Force and United States Indo-Pacific Command and maritime deliveries from Royal Netherlands Navy and commercial partners like Maersk. Funding and appeals were managed through mechanisms with IFRC and donor coordination by the World Bank and Asian Development Bank.

Aftermath, investigations, and reconstruction efforts

Post-disaster investigations by multidisciplinary teams from BMKG, Badan Geologi, USGS, GFZ, and academic institutions produced reports on fault slip, tsunami modeling, and liquefaction susceptibility; results informed revisions to the Indonesia Tsunami Early Warning System and coastal zoning regulations enforced by regional governments of Central Sulawesi. Reconstruction programs funded by national budgets, World Bank loans, and bilateral aid targeted housing, resilient infrastructure, and risk reduction projects implemented by BRR-style agencies and local governments, with community participation supported by UNDP and Asian Development Bank technical assistance. Legal and policy debates involved parliamentarians of the People's Representative Council (Indonesia) and provincial planners about land use, building codes aligned with SNI standards, and the integration of indigenous knowledge from groups documented by National Research and Innovation Agency (BRIN collaborators. International conferences and symposiums at United Nations University, Australian National University, and Università degli Studi di Padova disseminated lessons for tsunami science, early warning, and resilient urban design.

Category:2018 earthquakes in Indonesia