| New Guinea Trench | |
|---|---|
 The New Guinea Trench runs parallel to the northern coast of New Guinea | |
| Location | northern coast of New Guinea |
| Country | Indonesia, Papua New Guinea |
| Tectonics | |
| Plate | Australian Plate Pacific Plate |
| Type | Subduction zone |
The New Guinea Trench is a trench along the northern coast of New Guinea. It may represent the seafloor expression of an active subduction zone.
The tectonic regime in the Indonesian and Papua New Guinea region of the southwestern Pacific Ocean is dominated by oblique convergence between the Australian and Pacific Plates. The convergence resulted in the formation of several microplates to accommodate the tectonic strain. Convergence is mainly accommodated by either subduction along the New Guinea Trench or collision along the Highlands Fold and thrust belt on New Guinea. Subduction of oceanic plate beneath New Guinea occurs in a southwesternly direction. [1]
The trench runs north of New Guinea for 700 km (430 mi). Subduction is active along the trench from Indonesia to Papua New Guinea. Along the trench, the slab subduction angle varies from 10° to 30°. The slab can also be traced to 300 km (190 mi) depth beneath the island. [1] It is interpreted as a geological feature that accommodates oblique convergence between the Pacific Plate and the New Guinea Highlands although its quantified parameters remains undetermined. Due to the moderate seismicity along the trench, it is thought to be accommodating strain through aseismic creep for most of its length. [2]
The 17 February 1996 earthquake near Biak was the largest recorded earthquake along the trench, at Mw 8.2. The earthquake rupture geometry was consistent with the geometry of the trench and its aftershocks displayed thrust, strike-slip and normal focal mechanisms. A Mw 7.0 earthquake in Aitape, Papua New Guinea, displayed thrust-faulting mechanism, and was determined to have occurred on the plate boundary fault interface. Another Mw 7.6 earthquake occurred along the trench fault in 2002. [1]
A destructive MPAS 7.9 earthquake with an epicenter between Yapen and the Bird's Head Peninsula produced a significant tsunami. It caused substantial damage on the west coast of Yapen. The tsunami was also recorded in Honolulu, Hawaii, suggesting a source in the Pacific Ocean, possibly the New Guinea Trench. The 1996 tsunami was not recorded in Hawaii suggesting the 1914 event may have been larger. [3]
A convergent boundary is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, orogenesis, destruction of lithosphere, and deformation. Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types.
The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately 100 million years ago when India broke away and began moving north. Australia and Antarctica had begun rifting by 96 million years ago and completely separated a while after this, some believing as recently as 45 million years ago, but most accepting presently that this had occurred by 60 million years ago.
Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.
The Indonesian island of Sumatra is located in a highly seismic area of the world. In addition to the subduction zone off the west coast of the island, Sumatra also has a large strike-slip fault, the Great Sumatran Fault also known as Semangko Fault, running the entire length of the island. This fault zone accommodates most of the strike-slip motion associated with the oblique convergence between the Indo-Australian and Eurasian plates. The fault ends in the north just below the city of Banda Aceh, which was devastated in the 2004 Indian Ocean earthquake. After the December 2004 earthquake, pressure on the Great Sumatran Fault has increased tremendously, especially in the north.
The Queen Charlotte Fault is an active transform fault that marks the boundary of the North American plate and the Pacific plate. It is Canada's right-lateral strike-slip equivalent to the San Andreas Fault to the south in California. The Queen Charlotte Fault forms a triple junction south with the Cascadia subduction zone and the Explorer Ridge. The Queen Charlotte Fault (QCF) forms a transpressional plate boundary, and is as active as other major transform fault systems in terms of slip rates and seismogenic potential. It sustains the highest known deformation rates among continental or continent-ocean transform systems globally, accommodating greater than 50mm/yr dextral offset. The entire approximately 900 km offshore length has ruptured in seven greater than magnitude 7 events during the last century, making the cumulative historical seismic moment release higher than any other modern transform plate boundary system.
The Solomon Sea Plate is a minor tectonic plate to the northwest of the Solomon Islands archipelago in the south Pacific Ocean. It roughly corresponds with the Solomon Sea east of Papua New Guinea. The plate boundaries are associated with high earthquake activity as part of the New Britain subduction zone.
The 1,600 kilometres (990 mi) long Macquarie Fault Zone is a major right lateral-moving transform fault along the seafloor of the south Pacific Ocean which runs from New Zealand southwestward towards the Macquarie Triple Junction. It is also the tectonic plate boundary between the Australian Plate to the northwest and the Pacific Plate to the southeast. As such it is a region of high seismic activity and recorded the largest strike-slip event on record up to May 23, 1989, of at least Mw8.0
The South Bismarck Plate is a small tectonic plate located mainly in the southern Bismarck Sea. The eastern part of New Guinea and the island of New Britain are on this plate. It is associated with high earthquake and volcanic activity as part of the New Britain subduction zone within the Pacific Ring of Fire.
The 2000 New Ireland earthquakes occurred off the coast of New Ireland Province, Papua New Guinea on November 16 and 17.
The Aleutian Arc is a large volcanic arc of islands extending from the Southwest tip of the U.S. state of Alaska to the Kamchatka Peninsula of the Russian Federation.
The 1996 Biak earthquake, or the Irian Jaya earthquake, occurred on 17 February at 14:59:30 local time near Biak Island, Indonesia. The earthquake, which occurred on the New Guinea Trench, had a moment magnitude of 8.2 and a maximum Mercalli intensity of IX (Violent). The run-up height of the generated tsunami reached 7.7 m (25 ft). The disaster left at least 108 people dead, 423 injured, and 58 missing. It damaged or destroyed 5,043 houses which subsequently made another 10,000 homeless. At Korim, 187 houses were destroyed. Various countries and organizations provided aid and relief in the aftermath of the earthquake.
The Hikurangi Margin is New Zealand's largest subduction zone and fault.
An earthquake occurred off the coast of the Alaska Peninsula on July 28, 2021, at 10:15 p.m. local time. The large megathrust earthquake had a moment magnitude of 8.2 according to the United States Geological Survey (USGS). A tsunami warning was issued by the National Oceanic and Atmospheric Administration (NOAA) but later cancelled. The mainshock was followed by a number of aftershocks, including three that were of magnitude 5.9, 6.1 and 6.9 respectively.
Oblique subduction is a form of subduction for which the convergence direction differs from 90° to the plate boundary. Most convergent boundaries involve oblique subduction, particularly in the Ring of Fire including the Ryukyu, Aleutian, Central America and Chile subduction zones. In general, the obliquity angle is between 15° and 30°. Subduction zones with high obliquity angles include Sunda trench and Ryukyu arc.
On September 9, 2002, a magnitude 7.6 earthquake struck off the coast of Wewak, Sandaun Province, Papua New Guinea. The shallow reverse earthquake triggered a local tsunami measuring 5 meters high. The disaster resulted in at least 6 deaths, 70 injuries and building damage.
The 1979 Yapen earthquake occurred on September 12 at 05:17:51 UTC. It had an epicenter near the coast of Yapen Island in Irian Jaya, Indonesia. Measuring 7.5 on the moment magnitude scale and having a depth of 20 km (12 mi), it caused severe damage on the island. At least 115 were killed due to shaking and a moderate tsunami.
The Vanuatu subduction zone is currently one of the most active subduction zones on Earth, producing great earthquakes, with potential for tsunami hazard to all coastlines of the Pacific Ocean. There are active volcanoes associated with arc volcanism.
The Trobriand Plate was, and likely is, an independent microplate between New Guinea and the Solomon Islands. It has some unique geology, having the presence of the youngest metamorphic core complexes on earth. If there is presently active subduction between it and the Solomon Plate, at the Trobriand Trough, it continues to be an active microplate. Otherwise in the latest tectonic models it has merged with the Solomon Sea Plate, which becomes somewhat larger than predicted by Bird's 2003 model of Tectonic Plates. As a smaller Solomon Sea Plate is totally underwater, global positioning data can not resolve this issue. The area of the plate is associated with earthquake and volcanic activity as part of the Pacific Ring of Fire.
The New Britain subduction zone is one of the most recently formed and most active subduction zones on earth, producing great earthquakes, with potential for tsunami hazard, and being associated with active volcanism, as part of the Pacific Ring of Fire. It has a close relationship to an area of subduction tectonic activity that extends south eastward from New Britain to the Vanuatu subduction zone, involving the north eastern portion of the Australian Plate and its complicated collision dynamics with the south-western portion of the Pacific Plate.
{{cite journal}}: CS1 maint: multiple names: authors list (link)