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Wairoa North Fault
The Wairoa North Fault has a maximum potential for normal fault rupture and is the closest known active fault to the city of Auckland being to the south east. Geology The Wairoa North Fault is along the western aspect of the Hunua Ranges which is a horst with a mesozoic greywacke basement between it and the inferred inactive Firth of Thames Fault. There are multiple inferred inactive faults in the ranges but the area of the Wairoa North Fault was discovered to be seismologically active with low magnitude earthquakes after recordings began in the 1950s. The fault has 3 segments with potential for full rupture events every 12,600 years. To the north the faults now inactive extensions created the Clevedon Valley, and to the south these extensions separates the highest part of the Hunua Ranges from the Happy Valley basin. The fault appears to be along the eastern border of the Stokes Magnetic Anomaly System (New Zealand Junction Magnetic Anomaly) that essentially goes down al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wairoa
Wairoa is a town and territorial authority district in New Zealand's North Island. The town is the northernmost in the Hawke's Bay region, and is located on the northern shore of Hawke Bay at the mouth of the Wairoa River and to the west of Māhia Peninsula. It is on State Highway 2, northeast of Napier, and southwest of Gisborne. Wairoa is the nearest town to the Te Urewera protected area and former national park that is accessible from Wairoa via State Highway 38. It is the largest town in the district of Wairoa, and is one of three towns in New Zealand where Māori outnumber other ethnicities, with 62.29% of the population identifying as Māori. History Early history Te Wairoa was originally a Māori settlement. The ancestral waka (canoe) Tākitimu travelled up the river and landed at Mākeakea, near where Tākitimu meeting house stands today. The Wairoa river (full name: Te Wairoa Hōpūpū Hōnengenenge Matangirau) was an important source of food as well as a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A ''fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clevedon, New Zealand
Clevedon, previously known as Wairoa South, is a rural town in Auckland, New Zealand, located in the Franklin ward, one of the thirteen administrative divisions of Auckland city. The town is governed by the Auckland Council. The town is the centre of an administrative ward of Franklin which takes in much of the largely rural area to the east of the urban heart of the city. Clevedon is located on the Wairoa River five kilometres from its estuary and outflow into the Tamaki Strait, an arm of the Hauraki Gulf. It is 14 kilometres from the centre of the suburb of Manukau, which lies to the northwest. To the south of Clevedon rise the rugged hills of the Hunua Ranges. Several popular beaches are located on the coast close to Clevedon, including Duder's Beach and Kawakawa Bay. Between these two beaches lies the Duder Regional Park. History and culture Pre-European history Prior to human settlement, the area was swampy, and Bush moa, Mantell's moa and North Island giant moa b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motutapu Island
Motutapu Island (otherwise known as ''Motutapu'') is a island in the Hauraki Gulf to the northeast of the city of Auckland, New Zealand. The island is part of the Hauraki Gulf Maritime Park. Its full name, rarely used, is ''Te Motutapu a Taikehu'', "The sacred island of Taikehu", Taikehu having been a tohunga (tribal priest) of the Tainui iwi. 'Motutapu', meaning "sacred" or "sanctuary" island, is a term used for various islands in a number of Polynesian cultures. The island can be accessed via regular ferry services departing from Auckland City. Geography Approximately 18,000 years ago during the Last Glacial Maximum when sea levels were over 100 metres lower than present day levels, Motutapu Island was landlocked to the North Island, surrounded by a vast coastal plain where the Hauraki Gulf / Tīkapa Moana exists today. Sea levels began to rise 7,000 years ago, after which Motutapu became an island separated from the rest of New Zealand. The island is now linked by an artif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangitoto
Rangitoto Island is a volcanic island in the Hauraki Gulf near Auckland, New Zealand. The wide island is a symmetrical shield volcano cone, reaching a height of . Rangitoto is the youngest and largest of the approximately 50 volcanoes of the Auckland volcanic field, with its present form related to an eruption about 600 years ago and covering an area of . It is separated from the mainland of Auckland's North Shore by the Rangitoto Channel. Since World War II, it has been linked by a causeway to the much older, non-volcanic Motutapu Island. is Māori for 'Bloody Sky',What happened to local Maori? (from the Rangitoto page on the website) with the name coming from the full phras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stokes Magnetic Anomaly
The Stokes Magnetic Anomaly (also known as the Stokes Magnetic Anomaly System, SMAS, New Zealand Junction Magnetic Anomaly, JMA, great Nelson magnetic disturbance, Junction Anomaly, Campbell Magnetic Anomaly System, CMAS) is a magnetic anomaly on the Earth's surface that extends from New Caledonia to the Chatham Rise with complexity consistent with the theory of plate tectonics. History It is named after Captain (later Admiral) John Lort Stokes by G. C. Farr in 1916 as he described it first although such naming has proved controversial, hence many of the alternative names. The magnetic declinations were observed by Captain Stokes when captaining HMS Acheron and Commander (later Admiral) Byron Drury in HMS Pandora between 1851 and 1853. Geology The Stokes Magnetic Anomaly has been characterised for over and was essential for understanding the geology of Zealandia as a mainly underwater continent. It extends from south of New Caledonia to almost the eastern edge of the Camp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greywacke
Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lithic fragments set in a compact, clay-fine matrix. It is a texturally immature sedimentary rock generally found in Paleozoic strata. The larger grains can be sand- to gravel-sized, and matrix materials generally constitute more than 15% of the rock by volume. The term "greywacke" can be confusing, since it can refer to either the immature (rock fragment) aspect of the rock or its fine-grained (clay) component. The origin of greywacke was unknown until turbidity currents and turbidites were understood, since, according to the normal laws of sedimentation, gravel, sand and mud should not be laid down together. Geologists now attribute its formation to submarine avalanches or strong turbidity currents. These actions churn sediment and cause mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horst (geology)
In physical geography and geology, a horst is a raised fault block bounded by Fault (geology), normal faults. Horsts are typically found together with Graben, grabens. While a horst lifted or remains stationary, the grabens on either side Subsidence, subside. This is often caused by Extensional tectonics, extensional forces pulling apart the crust. Horsts may represent features such as plateaus, mountains, or ridges on either side of a valley. Horsts can range in size from small fault-blocks, up to large regions of stable continent that have not been not folded or warped by tectonic forces. The word ''Horst'' in German language, German means "mass" or "heap," and was first used in the geological sense in 1883 by Eduard Suess in ''The Face of the Earth.''Originally published in 1883 in German as "Das Antlitz der Erde", translated and published in English in 1904 Geomorphology Horsts may have either symmetrical or asymmetrical cross-sections. If the normal faults to either side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hunua Ranges
The Hunua Ranges is a mountain range and regional park to the southeast of Auckland city, in the Auckland and Waikato regions of New Zealand's North Island. The ranges cover some and rise to 688 metres (2255 ft) at Kohukohunui.Hunua Ranges , ''An Encyclopaedia of New Zealand'', edited by A. H. McLintock, originally published in 1966. Te Ara - The Encyclopedia of New Zealand, updated 26 September 2006. Accessed 15 March 2007. owns and manages of the ranges, including part located in the Waikato region, as a regional park open to the public. Geography The ranges are located approximately 50 kilometres (30 mi) southeast of ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...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] |
Hauraki Rift
The Hauraki Rift is an active NeS-to NWeSE-striking rift valley system in the North Island of New Zealand that has produced the Firth of Thames and the Hauraki Plains. It is approximately wide and long. Geology The rift valley in the north appears to be delimited in the west by the line of the Firth of Thames Fault and to the east by the Hauraki Fault. The mountains of the Coromandel (which include andesitic and basaltic back arc volcanoes) and Kaimai Range to the east and the Hunua Range to the west give it the appearance of a full graben although it has also been described as a simple structure of 2 to 3 half-grabens so the term Hauraki Graben for the low lying portions would be incorrect. However the apparent line in the south of the Firth of Thames Fault no longer follows the apparent horst structure to the west and some believe the line of the Waikato River after it leaves the old Taupō Rift gives a better guide to the western line of the rift as structures have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
