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Wairarapa Fault
The Wairarapa Fault is an active seismic fault in the southern part of the North Island of New Zealand. It is a dextral (right lateral) strike-slip fault with a component of uplift to the northwest as expressed by the Rimutaka Range. It forms part of the North Island Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate. Geometry The Wairarapa Fault continues south of Lake Wairarapa as the Wharekauhau thrust, which can be traced on the seabed in the Cook Strait for about 30 km with a possible further continuation on a fault strand lying to the northwest. These faults segments are considered likely to be the active traces of the southern Wairarapa Fault. At its northeastern end the fault terminates near Mauriceville, with the displacement apparently continued on the Pa Valley and Alfredton Faults. Seismicity Rupture along the Wairarapa Fault and Wharekauhau thrust was responsible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1855 Wairarapa Earthquake
The 1855 Wairarapa earthquake occurred on 23 January at about 9.17 p.m., affecting much of the Cook Strait area of New Zealand, including Marlborough in the South Island and Wellington and the Wairarapa in the North Island. In Wellington, close to the epicentre, shaking lasted for at least 50 seconds. The moment magnitude of the earthquake has been estimated as 8.2, the most powerful recorded in New Zealand since systematic European colonisation began in 1840. This earthquake was associated with the largest observed movement on a strike-slip fault, maximum . It has been suggested that the surface rupture formed by this event helped influence Charles Lyell to link earthquakes with rapid movement on faults. Tectonic setting New Zealand lies along the boundary between the Australian and Pacific Plates. In the South Island most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wellington Fault
The Wellington Fault is an active seismic fault in the southern part of the North Island of New Zealand. It is a dextral (right-lateral) strike-slip fault with variable amounts of vertical movement causing uplift to the northwest, as expressed by a series of ranges. It forms part of the North Island Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate. Geometry The Wellington Fault consists of three main sections. Wellington-Hutt Valley section This 75 km long curved fault segment is mapped on the floor of the Cook Strait before crossing the Wellington peninsula through Long Gully and along the northwestern edge of Wellington Harbour, past Lower Hutt terminating near Kaitoke. This segment has had a lateral slip-rate of 6.0–7.6 mm per year for at least the last 140,000 years, from the progressive offset of dated river terraces. The most recent rupture event along thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of The Wellington Region
The Wellington Region of New Zealand has a foundation of Torlesse Greywacke rocks, that make up the Tararua and Rimutaka Ranges, that go from Wellington in the south to the Manawatū Gorge, where they are renamed as the Ruahine Ranges, and continue further north-northeast, towards East Cape. To the west of the Tararua Ranges are the Manawatū coastal plains. To the east of the Ruahine Ranges is the Wairarapa-Masterton Basin, then the Eastern Uplands that border the eastern coast of the North Island from Cape Palliser to Napier. To the east of the North Island is the Hikurangi Trough, a collision zone between the Pacific Plate and the Australian Plate. The Pacific Plate is being subducted under the Australian Plate, compressing the Wellington Region, and causing the North Island Fault System, and a series of SSW-NNE trending basins and ranges, including the Tararua and Rimutaka Ranges, and the Wairarapa-Masterton Basin. Successively newer rocks have been accreted to the east co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of New Zealand
The geology of New Zealand is noted for its volcanic activity, earthquakes and geothermal areas because of its position on the boundary of the Australian Plate and Pacific Plates. New Zealand is part of Zealandia, a microcontinent nearly half the size of Australia that broke away from the Gondwanan supercontinent about 83 million years ago. New Zealand's early separation from other landmasses and subsequent evolution have created a unique fossil record and modern ecology. New Zealand's geology can be simplified into three phases. First the basement rocks of New Zealand formed. These rocks were once part of the super-continent of Gondwana, along with South America, Africa, Madagascar, India, Antarctica and Australia. The rocks that now form the, mostly submerged, continent of Zealandia were then nestled between Eastern Australia and Western Antarctica. Secondly New Zealand drifted away from Gondwana and many sedimentary basins formed, which later became the sedimentary rocks cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Before Present
Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1 January 1950 as the commencement date (epoch) of the age scale. The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must now account for. In a convention that is not always observed, many sources restrict the use of BP dates to those produced with radiocarbon dating; the alternative notation RCYBP stands for the explicit "radio carbon years before present". Usage The BP scale is sometimes used for dates established by means other than radiocarbon dating, such as stratigraphy. This usage differs from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turakirae Head
Turakirae Head is a promontory on the southern coast of New Zealand's North Island. It is located at the western end of Palliser Bay, 20 kilometres southeast of Wellington, at the southern end of the Remutaka Range. The head is an excellent example of tectonic uplift within the Wellington region. There are a series of raised terraces which show where the shoreline existed prior to large seismic events. The Turakirae Head is also home to a seal colony and southern bull kelp. Turakirae also marks the southernmost coastal boundary point for the Ngāti Kahungunu Ngāti Kahungunu is a Māori iwi located along the eastern coast of the North Island of New Zealand. The iwi is traditionally centred in the Hawke's Bay and Wairārapa regions. The tribe is organised into six geographical and administrative ... tribe which extends as north as Paritu which is just north south of Gisborne. References Headlands of the Wellington Region Cook Strait {{Wellington-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beach Ridge
A beach ridge is a wave-swept or wave-deposited ridge running parallel to a shoreline. It is commonly composed of sand as well as sediment worked from underlying beach material. The movement of sediment by wave action is called ''littoral transport''. Movement of material parallel to the shoreline is called ''longshore transport''. Movement perpendicular to the shore is called ''on-offshore transport''. A beach ridge may be capped by, or associated with, sand dunes. The height of a beach ridge is affected by wave size and energy. A fall in water level (or an uplift of land) can isolate a beach ridge from the body of water that created it. Isolated beach ridges may be found along dry lakes in the western United States and inland of the Great Lakes of North America, where they formed at the end of the last ice age when lake levels were much higher due to glacial melting and obstructed outflow caused by glacial ice. Some isolated beach ridges are found in parts of Scandinavia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cook Strait
Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A H, Ed. (1966''Cook Strait''from An Encyclopaedia of New Zealand, updated 18-Sep-2007. Note: This is the distance between the North Island and Arapaoa Island; some sources give a slightly larger reading of around , that between the North Island and the South Island. and is considered one of the most dangerous and unpredictable waters in the world. Regular ferry services run across the strait between Picton in the Marlborough Sounds and Wellington. The strait is named after James Cook, the first European commander to sail through it, in 1770. In Māori it is named ''Te Moana-o-Raukawa'', which means ''The Sea of Raukawa''. Raukawa is a type of woody shrub native to New Zealand. History Approximately 18,000 years ago during the Last Gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Fault
An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years. * Active faulting is considered to be a geologic hazard - one related to earthquakes as a cause. Effects of movement on an active fault include strong ground motion, surface faulting, tectonic deformation, landslides and rockfalls, liquefaction, tsunamis, and seiches. Quaternary faults are those active faults that have been recognized at the surface and which have evidence of movement during the Quaternary Period. Related geological disciplines for ''active-fault'' studies include geomorphology, seismology, reflection seismology, plate tectonics, geodetics and remote sensing, risk analysis, and others. Location Active faults tend to occur in the vicinity of tectonic plate boundaries, and active fault research has foc ... [...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] |
Indo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and the surrounding ocean and extends northwest to include the Indian subcontinent and the adjacent waters. It was formed by the fusion of the Indian and the Australian Plates approximately 43 million years ago. The fusion happened when the mid-ocean ridge in the Indian Ocean, which separated the two plates, ceased spreading. Regions India, Australia, New Guinea, Tasmania, New Zealand, and New Caledonia are all fragments of the ancient supercontinent of Gondwana. As the ocean floor broke apart, these land masses fragmented from one another, and for a time these centers were thought to be dormant and fused into a single plate. However, research in the early 21st century indicates plate separation of the Indo-Australian Plate may have already occurred. Characteristics The eastern side of the plate is the convergent boundary with the Pacific plate. The Pacific plate sinks below the Aust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
