|
2004 Tasman Sea Earthquake
The 2004 Tasman Sea earthquake, also known as the 2004 Macquarie Island earthquake, was a very large magnitude 8.1 earthquake which struck a remote area of the southern Tasman Sea in the early morning hours of Friday 24 December 2004. Its epicentre was located roughly northwest of the Auckland Islands of New Zealand, and roughly north of Macquarie Island of Australia. Shaking was reportedly felt as far as Tasmania and the South Island. The event was a complex intraplate earthquake within the Australian Plate, which generated a small tsunami. Tectonic setting The region to the south of New Zealand involves a complex boundary between the Pacific Plate and the Australian Plate. Immediately to the south of the South Island is the Puysegur Trench, where the Australian Plate is subducting obliquely under the Pacific Plate. To the south of this, the Macquarie Fault Zone is a dextral (right lateral) transform boundary. Further south, the Australian Plate is subducting underneath t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time In Australia
Australia uses three main time zones: Australian Western Standard Time (AWST; UTC+08:00), Australian Central Standard Time (ACST; UTC+09:30), and Australian Eastern Standard Time (AEST; UTC+10:00). Time is regulated by the individual state governments, some of which observe daylight saving time (DST). Australia's external territories observe different time zones. Standard time was introduced in the 1890s when all of the Australian colonies adopted it. Before the switch to standard time zones, each local city or town was free to determine its local time, called local mean time. Now, Western Australia uses Western Standard Time; South Australia and the Northern Territory use Central Standard Time; while New South Wales, Queensland, Tasmania, Victoria, Jervis Bay Territory, and the Australian Capital Territory use Eastern Standard Time. Daylight saving time (+1 hour) is used in jurisdictions in the south and south-east: South Australia, New South Wales, Victoria, Tasmania, Je ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Izanagi Plates. The Pacific Plate subsequently grew to where it underlies most of the Pacific Ocean basin. This reduced the Farallon Plate to a few remnants along the west coast of North America and the Phoenix Plate to a small remnant near the Drake Passage, and destroyed the Izanagi Plate by subduction under Asia. The Pacific Plate contains an interior hot spot forming the Hawaiian Islands. Boundaries The north-eastern side is a divergent boundary with the Explorer Plate, the Juan de Fuca Plate and the Gorda Plate forming respectively the Explorer Ridge, the Juan de Fuca Ridge and the Gorda Ridge. In the middle of the eastern side is a transform boundary with the North American Plate along the San Andreas Fault, and a boundary with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port Kembla, New South Wales
Port Kembla is a suburb of Wollongong 8 km south of the CBD and part of the Illawarra region of New South Wales. The suburb comprises a seaport, industrial complex (one of the largest in Australia), a small harbour foreshore nature reserve, and a small commercial sector. It is situated on the tip of Red Point (Port Kembla), Red Point: its first European sighting was by Captain James Cook in 1770. The name "Kembla" is an Aboriginal Australians, Aboriginal word meaning "plenty [of] wild fowl". History Before Port Kembla was an industrial suburb of Wollongong, it was a town with a remarkably self-sufficient society, a growing commercial centre, and a vibrant civic life. Town subdivision began in 1908, and by 1921 there were 1622 residents. Economic expansion propelled further population growth. Port Kembla derives its name from its proximity to Mount Kembla. Industrial change A copper smelter and refinery, the Electrolytic Refinery and Smelting Company of Australia, began pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glamorgan–Spring Bay Council
Glamorgan-Spring Bay Council is a local government body in Tasmania, situated on the central east coast of the state. Glamorgan-Spring Bay is classified as a rural local government area and has a population of 4,528, the major towns of the region include Bicheno, Orford and Triabunna with Swansea the principal town. History and attributes Glamorgan-Spring Bay was established on 2 April 1993 after the amalgamation of the Municipality of Glamorgan and Municipality of Spring Bay. The council derives its name from the region of Glamorgan in Wales. Glamorgan-Spring Bay is classified as rural, agricultural and medium (RAM) under the Australian Classification of Local Governments. The Maria Island and Freycinet national parks are contained in the region. Suburbs Not in above list * Douglas River * Freycinet Peninsula * Maria Island * Nugent * Runnymede * Schouten Island * Tooms Lake * Woodsdale See also *List of local government areas of Tasmania Councils of Tasmania ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macquarie Island Station
The Macquarie Island Station is a permanent Australian subantarctic research base on Macquarie Island, commonly called Macca, situated in the Southern Ocean and located approximately halfway between mainland Australia and Antarctica, managed by the Australian Antarctic Division (AAD). The station lies at the base of Wireless Hill, between two bays on the isthmus at the northern end of the island. The island and its surrounding waters are administered as a nature reserve by the Tasmanian Government Parks and Wildlife Service. In 1997 the island was inscribed on the UNESCO World Heritage List as a site of major geoconservation significance, being the only place on earth where rocks from the earth's mantle are actively exposed above sea-level. Purpose The research station is operated by the Australian Antarctic Division. Scientific research on the island is focused around biology, geosciences, meteorology, and human impact on the environment. Macquarie island birds breed on the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2004 Indian Ocean Earthquake And Tsunami
An earthquake and a tsunami, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time (UTC+7) on 26 December 2004, with an epicentre off the west coast of northern Sumatra, Indonesia. It was an undersea megathrust earthquake that registered a magnitude of 9.1–9.3 , reaching a Mercalli intensity up to IX in certain areas. The earthquake was caused by a rupture along the fault between the Burma Plate and the Indian Plate. A series of massive tsunami waves grew up to high once heading inland, after being created by the underwater seismic activity offshore. Communities along the surrounding coasts of the Indian Ocean were devastated, and the tsunamis killed an estimated 227,898 people in 14 countries, making it one of the deadliest natural disasters in recorded history. The direct results caused major disruptions to living conditions and commerce in coastal provinces of surrounded countries, including Ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fracture Zone
A fracture zone is a linear feature on the ocean floor—often hundreds, even thousands of kilometers long—resulting from the action of offset mid-ocean ridge axis segments. They are a consequence of plate tectonics. Lithospheric plates on either side of an active transform fault move in opposite directions; here, strike-slip activity occurs. Fracture zones extend past the transform faults, away from the ridge axis; seismically inactive (because both plate segments are moving in the same direction), they display evidence of past transform fault activity, primarily in the different ages of the crust on opposite sides of the zone. In actual usage, many transform faults aligned with fracture zones are often loosely referred to as "fracture zones" although technically, they are not. Structure and formation Mid-ocean ridges are divergent plate boundaries. As the plates on either side of an offset mid-ocean ridge move, a transform fault forms at the offset between the two ridges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mid-ocean Ridge
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary. The rate of seafloor spreading determines the morphology of the crest of the mid-ocean ridge and its width in an ocean basin. The production of new seafloor and oceanic lithosphere results from mantle upwelling in response to plate separation. The melt rises as magma at the linear weakness between the separating plates, and emerges as lava, creating new oceanic crust and lithosphere upon cooling. The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. Most oceanic spreading centers are not in the middle of their hosting ocean basis but regardless, are traditionally called mid-ocean rid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Divergent Boundary
In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent boundaries within continents initially produce rifts, which eventually become rift valleys. Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges. Current research indicates that complex convection within the Earth's mantle allows material to rise to the base of the lithosphere beneath each divergent plate boundary. This supplies the area with huge amounts of heat and a reduction in pressure that melts rock from the asthenosphere (or upper mantle) beneath the rift area, forming large flood basalt or lava flows. Each eruption occurs in only a part of the plate boundary at any one time, but when it does occur, it fills in the opening gap as the two opposing plates move away from each other. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euler's Rotation Theorem
In geometry, Euler's rotation theorem states that, in three-dimensional space, any displacement of a rigid body such that a point on the rigid body remains fixed, is equivalent to a single rotation about some axis that runs through the fixed point. It also means that the composition of two rotations is also a rotation. Therefore the set of rotations has a group structure, known as a ''rotation group''. The theorem is named after Leonhard Euler, who proved it in 1775 by means of spherical geometry. The axis of rotation is known as an Euler axis, typically represented by a unit vector . Its product by the rotation angle is known as an axis-angle vector. The extension of the theorem to kinematics yields the concept of instant axis of rotation, a line of fixed points. In linear algebra terms, the theorem states that, in 3D space, any two Cartesian coordinate systems with a common origin are related by a rotation about some fixed axis. This also means that the product of two rot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hjort Trench
The Hjort Trench is a linear topographic depression south of Macquarie Island in the southwest Pacific Ocean. Geologically, the depression is considered to be the seafloor expression of an ocean-ocean subduction zone, where the Australian plate is thrusting beneath the Pacific Plate. As the southernmost portion of the Macquarie Ridge Complex, the Hjort Trench lies in an area of diagonal convergence produced by the transform fault evolution of the Emerald Fracture Zone. Frequent seismic events, most less than deep, characterize the transpression along this plate boundary.Lodolo, E. and F. Coren (1994). "The Westernmost Pacific Antarctic plate boundary in the vicinity of the Macquarie triple junction." (In C.A. Ricci, ed. Terra Antarctica, vol.1). pp. 158–161 The trench is named in honour of the Norwegian oceanographer Johan Hjort. Geomorphology The deepest point of Hjort Trench is approximately below sea level. To the east, the Hjort ridge follows the general curve of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transform Fault
A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone. A transform fault is a special case of a ''strike-slip fault'' that also forms a plate boundary. Most such faults are found in oceanic crust, where they accommodate the lateral offset between segments of divergent boundaries, forming a zigzag pattern. This is a result of oblique seafloor spreading where the direction of motion is not perpendicular to the trend of the overall divergent boundary. A smaller number of such faults are found on land, although these are generally better-known, such as the San Andreas Fault and North Anatolian Fault. Nomenclature Transform boundaries are also known as conservative plate boundaries because they involve no addition or loss of lithosphere at the Earth's surface. Background Geophysicist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
