Sorong fault also (Sorong Fault Zone, SFZ) is an active, broad zone of inferred left lateral shear at the

triple junction A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can ...

of the

Australian plate 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 when India broke ...

Eurasian plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

, and

Pacific plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and I ...

s, where many plate fragments exist, such as the

Philippine Sea Plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...

, Bird's Head Plate,

Halmahera Plate Halmahera Plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia. Regional tectonics The tectonic setting of the Molucca Sea region is unique. It is the only global example of an ac ...

and the

Molucca Sea Plate Located in the western Pacific Ocean near Indonesia, the Molucca Sea Plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex. The Molucca Sea Plate represents the only known example ...

. It has been implicated in numerous large

earthquakes An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

. It is one of the two major faults created by the Australian and Pacific plate convergence, the other being the Ramu-Markham Fault zone. The fault triggered the destructive 1998 North Maluku earthquake which killed 41 people.

Location

The Sorong fault begins around Sulawesi and runs towards

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...

. It marks the boundary between Halmahera plate and Bird's Head Plate. The Sorong fault system has been documented to extend westward more than 500 miles (800 km) from Teluk Sarera to Kepulauan Banggai.

Geology

The fault zone juxtaposes

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non- avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

continental Continental may refer to: Places * Continent, the major landmasses of Earth * Continental, Arizona, a small community in Pima County, Arizona, US * Continental, Ohio, a small town in Putnam County, US Arts and entertainment * ''Continental'' (a ...

and

volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...

ophiolitic An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found ...

rocks.

Plate evolution

It is widely believed that fragments of the northern Australian continental margin in

are being detached and translated westward in this shear zone until they collide with the eastern margin of Eurasia (

Sundaland Sundaland (also called Sundaica or the Sundaic region) is a biogeographical region of South-eastern Asia corresponding to a larger landmass that was exposed throughout the last 2.6 million years during periods when sea levels were lower. It ...

) in the region of Sulawesi Island. However, the details of

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its ow ...

translation Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...

, amalgamation, and docking remain poorly documented at this time. In particular, the timing of events is very poorly constrained, with estimates for the commencement of the SFZ ranging from early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

or older to

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

. Investigations in the 1990s of the SFZ and the adjacent regions of Sulawesi and Irian Jaya (Indonesian New Guinea), including fieldwork in several of the SFZ island-terranes (

Waigeo Island Waigeo is an island in Southwest Papua province of eastern Indonesia. The island is also known as Amberi, or Waigiu. It is the largest of the four main islands in the Raja Ampat Islands archipelago, between Halmahera and about to the north-wes ...

Halmahera Halmahera, formerly known as Jilolo, Gilolo, or Jailolo, is the largest island in the Maluku Islands. It is part of the North Maluku province of Indonesia, and Sofifi, the capital of the province, is located on the west coast of the island. H ...

Bacan The Bacan Islands, formerly also known as the Bachans, Bachians, and Batchians, are a group of islands in the Moluccas in Indonesia. They are mountainous and forested, lying south of Ternate and southwest of Halmahera. The islands are administe ...

Obi Islands The Obi Islands (also known as Ombirah, Indonesian: ''Kepulauan Obi'') are a group of 42 islands in the Indonesian province of North Maluku, north of Buru and Ceram, and south of Halmahera. With a total area of 3,048.08 km2, they had a popu ...

, and

Sula Islands The Sula Islands Regency ( id, Kabupaten Kepulauan Sula) is one of the regencies in North Maluku province of Indonesia. It covers a land area of 3,338.67 km2 and consists of two of the three large islands comprising the Sula Archipelago, together w ...

), suggest a less mobilist interpretation of the region than previous reconstructions. SFZ did not begin to develop in its present form before the late Miocene.

References

Seismic faults of Southeast Asia Plate tectonics Geology of the Pacific Ocean Geology of Indonesia Seismic faults of Oceania Seismic faults of Indonesia {{tectonics-stub

Location

Geology

Plate evolution

See also

References