Mw6.8 Eastern Papua New Guinea Earthquake Report (7th of October 2023)

Mw6.8 Eastern Papua New Guinea Earthquake (7^th of October 2023) Information and Damage

On the evening of the 7^th of October 2023, eastern Papua New Guinea experienced two large seismic events of significant magnitude. The first one, with a magnitude of 6.7, occurred at 18:34 local time. The epicenter was located 56 kilometers (approximately 43.7 miles) southeast of Madang, the provincial capital of Madang Province, which is home to approximately 30,000 residents in Papua New Guinea’s eastern region.

Just six minutes later, at 18:40 local time, another substantial earthquake, registering a magnitude of 6.8, struck beneath the ocean approximately 112 kilometers (around 69.59 miles) southeast of Madang. This second earthquake occurred at a depth of 74 kilometers (45.9 miles).

In the wake of these two major seismic events, Papua New Guinea experienced additional tremors, numbering four in total, with magnitudes ranging from 4.4 to 5.7.

Papua New Guinea’s Prime Minister James Marape issued a statement on Monday, extending his heartfelt sympathies and support to the affected communities in Madang and surrounding areas. He assured that swift measures were being taken in response to this tragic disaster. In addition, authorities have been diligently assessing the extent of the damage and initiating repair efforts across Papua New Guinea. The National Disaster Office, in collaboration with government officials, is spearheading a comprehensive evaluation of the earthquake's impact and its effects on the local population.

There were no reports of injuries or fatalities; however, there has been some damage, among them plunging the entire province into darkness since Saturday night, resulting in substantial damage to Papua New Guinea’s Power generator, transmission, and distribution infrastructure.

Picture 1: Location of Mw6.8 Eastern Papua New Guinea earthquake (7^th of October 2023).

Seismic Activity in Papua New Guinea

Papua New Guinea, situated in the Pacific Ring of Fire, is no stranger to seismic activity. Earthquakes are a common occurrence in this diverse and remote nation, although they typically do not result in widespread damage. This is largely due to the country's unique geography, with most areas outside major towns and cities being sparsely populated and characterized by wooden structures.

However, there are moments when earthquakes do cause great damage. For example, in April 2023, a powerful 7.0 magnitude earthquake struck a jungle-clad region within this Pacific Island nation, leaving a trail of devastation in its wake. Tragically, at least seven lives were lost and approximately 180 homes were reduced to rubble in the Karawari area, close to the epicenter of the quake. This earthquake was a grim reminder of the region's vulnerability to seismic events. In September 2022, a formidable 7.6-magnitude earthquake wreaked havoc across the broader Madang province. The impact was profound, with over 400 homes collapsing.

The intense seismic activity in Papua New Guinea is primarily attributed to its location at the convergence of several tectonic plate boundaries. The Australian Plate to the south collides with the Pacific Plate to the north, resulting in complex interactions that generate significant stress and seismic events. Earthquakes can range from minor tremors to major quakes capable of causing significant damage. The most intense seismic activity in Papua New Guinea occurs in the New Guinea Fold and Thrust Belt, where the Australian Plate is colliding with and diving beneath the Pacific Plate. The region around the capital, Port Moresby, also experiences seismic activity.

Additionally, due to its location along the Pacific Ring of Fire, Papua New Guinea is also at risk of tsunamis triggered by undersea earthquakes. The country has experienced tsunamis in the past, some of which have resulted in loss of life and damage to coastal communities.

Quantectum’s Report on Mw6.8 Eastern Papua New Guinea Earthquake (7^th of October 2023)

At Quantectum, we’ve been closely monitoring the seismic situation in Papua New Guinea and analyzed the Mw6.7 Eastern Papua New Guinea earthquake (7^th of October 2023).

On the day of the earthquake occurrence, our models detected signs of intense stress tractions and instability in the region. The shear traction field, a crucial parameter in understanding tectonic dynamics, was notably elevated, which can be seen in the picture below. It shows that the shear traction field was elevated, and critical regions (black pixels) were also present. This indicates the strong tectonic instability of the area, where the forces acting on the Earth's crust had reached a critical point.

Picture 2: The shear traction field and critical regions in the area of Mw6.8 Eastern Papua New Guinea earthquake (7^th of October 2023).

According to the graph of our earthquake forecasting models for critical potential, the earthquakes occurred during a period when the probability was strongly elevated for all magnitudes. This graph sheds light on the relationship between seismic events and the underlying geophysical conditions. The mentioned elevation in seismic risk can be attributed directly to the presence of critical regions within the Earth's crust and an elevated shear traction field.

Picture 3: Critical potential in the time of Papua New Guinea earthquakes (7^th of October 2023).

In addition, Quantectum's hazard maps provide critical insight into the seismic risks faced by regions susceptible to earthquakes. These maps use a standardized scale to assess the intensity of shaking experienced during an earthquake event, helping communities and authorities prepare for potential disasters.

For this earthquake, the hazard map shows “VII” as the maximum intensity which corresponds to very strong shaking and moderate damages in the epicenter. This means buildings and infrastructure near the epicenter are likely to experience structural stress, which can result in observable damage. This can include cracks in walls and foundations, structural deformation, and even the potential for buildings to partially collapse in extreme cases.

Picture 4: The hazard map for Mw6.8 Eastern Papua New Guinea earthquake (7^th of October 2023).

In conclusion, the Mw6.8 earthquake that struck Papua New Guinea serves as a stark reminder of the significant seismic activity that characterizes this region. This seismic event, while not among the largest to occur globally, had some impacts locally, however, no great damage or injuries were reported.

Sources:

Hindustantimes. 2023. Magnitude 6.7 earthquake hits Papua New Guinea. Accessed on 10-Oct-2023. Available at: https://www.hindustantimes.com/world-news/magnitude-6-7-earthquake-hits-papua-new-guinea-101696669462949.html

Xinhua. 2023. Damage assessment, repair work underway in PNG following 6.7-magnitude quakes. Accessed on 10-Oct-2023. Available at: https://english.news.cn/20231009/a7c93ee78e954dd99c1204811224dbc5/c.html