The Papua New Guinea earthquake was a magnitude 7.5 earthquake that occurred in the Hela Province of Papua New Guinea on 26 February 2018 (25 February UTC), at 3:44 a.m. local time (25 February, 17:44 UTC). The earthquake's epicenter was west of the town of Komo. The maximum felt intensity was IX (Violent) on the Mercalli intensity scale. A total of 160 people were killed and many others were injured. An aftershock of M6.0 killed 11 people on 4 March, while another aftershock of M6.7 occurred at 00:13 local time on 7 March, killing at least 25 more. A 6.3 aftershock killed another 4 people on 7 April, more than a month after the first tremors hit the area.
Tectonic setting
Papua New Guinea lies within the complex zone of collision between the Australian Plate and the Pacific Plate, which converge at a rate of 107 mm per year at the earthquake's location. The Papuan fold and thrust belt, which is responsible for the mountainous New Guinea Highlands, forms the boundary between the Stable Platform area to the south and the Mobile Belt to the north. The Stable Platform consists of little deformed continental crust of the Australian Plate. The Mobile Belt consists of a series of arc terranes and continental fragments previously accreted to the Australian Plate. Current convergence across the fold and thrust belt are estimated at up to 15 mm per year. The thrusting is thick-skinned in type, involving reverse reactivation of much older extensional faults.
Earthquake
The main shock struck at a depth of 23.4 km below the northern slopes of Mt. Sisa, and was followed by a 5.5 Mb aftershock less than 30 minutes later. The Geohazards Management Division in Port Moresby characterized it as "typical for the Papuan fold and thrust belt".
Aftershocks
There have been more than 270 aftershocks reported by USGS in total, 68 of which were above magnitude 5, and 6 of which were above magnitude 6.
Impact
Papua New Guinea
A total of 160 people were reported to have been killed, while over 500 others were injured. Hela Province had at least 80 confirmed deaths, while 45 casualties were reported from the Southern Highlands Province. Thousands of houses were destroyed. Komo's airport runway was severely affected. Homes and properties were buried as the ground opened up and sank. There were 14 deaths in Mendi, while 18 people were killed in the Bosavi-Kutubu area.
Indonesia
The quake and its aftershocks caused panic in Jayapura, the capital of Indonesia's Papua province. The country's National Board for Disaster Management later confirmed that 12 buildings were damaged in the Boven Digoel Regency, including a mosque, a military post, and a district office. Landslides also blocked and damaged roads.
Aftershocks
On 4 March, a M6.0 aftershock killed 11 people after a landslide buried the small village of Huya. A further 25 people were reported killed by a M6.7 aftershock on 7 March. A M6.3 aftershock on 7 April caused more damage, and four people were killed when houses collapsed in Tari.
Aftermath
On the morning of 26 February, ExxonMobil announced that they would temporarily shut down the Hides gas field conditioning plant, situated about from the epicenter, in order to assess damage. Officials later confirmed that all of the staff were "safe and accounted for", while the administration buildings, living quarters, and mess hall had all sustained damage. The company was planning on evacuating all non-essential personnel. Flights into the Komo airfield were temporarily suspended until the runway could be surveyed. Sinkholes and landslides were reported across the affected areas, with electricity supplies also being disrupted. On 10 March, ExxonMobil officials announced that the Hides facility will not be operational for at least 8 weeks, a significant economic loss for the country.
Papua New Guinea's largest oil and gas exploration and development company Oil Search also announced it would shut down production in the Southern Highlands until it could ensure the safety of its employees. The Porgera Gold Mine suffered damage to its gas and electricity infrastructure, while landslips blocked the access road to the Ok Tedi Mine and damaged parts of the highway between Tabubil and Kiunga in the Western Province.