The result is a major earthquake along the Alpine fault. It forms a transform boundary between the Pacific Plate and the Indo-Australian Plate. The Alpine Fault runs for over 800km up the spine of the South Island. / Science Topics Conversely, in the southwest of South Island where the Australian Plate is being subducted below the Pacific Plate, the deeper earthquakes occur on the southeast edge of the seismic zone where the Benioff zone dips steeply to the southeast. Recent research by GNS Science has extended our knowledge of the Alpine fault earthquake record back through the past 8,000 years. The Southern Alps have been formed over millennia by upthrust from successive earthquakes on the Alpine Fault. Nobody can predict exactly when the Alpine Fault will next rupture but, tracing its geological record, it seems to occur around every three centuries. Using techniques like these, scientists such as Mark Yetton of the University of Canterbury have found out that major earthquakes happened on the central Alpine Fault in 1100, 1450, 1620 and 1717. The Alpine Fault is a geological fault, specifically a right-lateral strike-slip fault, that runs almost the entire length of New Zealand’s South Island. Recent research (published in 2012) by GNS Science has extended our knowledge of the Alpine fault earthquake record back through the past 8000 years. Earthquakes along the fault, and the associated earth movements, have formed the Southern Alps. An improved age for Earth’s latest magnetic field reversal using radiometric... ‘Steak-knife’ teeth reveal ecology of oldest land predators, New species of Jurassic reptile identified from skeletal remains, Using chaos to model geophysical phenomena, Jurassic world of volcanoes found in central Australia. Approximate rupture dates are 1717AD, 1620 AD, 1450 AD, and 1100 AD. The origin of the Alpine fault is located in the transition area between Fiordland and the Southern Alps … It forms a transform boundary between the Pacific Plate and the Indo-Australian Plate. This set of faults, which includes the Wairau Fault, the Hope Fault, the Awatere Fault, and the Clarence Fault, transfer displacement between the Alpine Fault and the Hikurangi subduction zone to the north. This pattern of deeper earthquakes towards the northwest of North Island reflects the northwest dip (or slope) of the boundary between the two plates (the Benioff zone). Tap to unmute. Current evidence suggests that the Alpine Fault formed during the early Miocene, which would date it somewhere around 20 million years ago. The glaciers and rivers have removed the rest of the material and spread it out across the lowland plains or onto the sea floor. The place which will be split apart by titanic forces when the Alpine Fault can't take the pressure anymore. Analysis of sediments deposited by previous earthquakes shows the last one here was in 1717, give or take a year or two. Alpine Fault Complex: The Alpine Fault and associated faults like the Awatere and Clarence (Fig. In between earthquakes, the Alpine Fault is locked. It’s the part of the active boundary between the Pacific and Australian tectonic plates where they intersect on land. The Alpine Fault has a high probability (estimated at 30%) of rupturing in the next 50 years. An earthquake on the Alpine Fault has two geological effects: mountains are pushed higher and the shaking breaks up rocks. Helens formed in a subduction zone. / Earthquakes Geologists and authorities are racing to quantify what might happen, and how they might respond in the event of the next one, likely to occur some time in the next 50 years. Each time it has ruptured, it has also moved vertically, lifting the Southern Alps in the process. In the last 12 million years the Southern Alps have been uplifted by an amazing 20 kilometres, and it is only the fast pace of erosion that has kept their highest point below 4000 metres. It’s the "on-land" boundary of the Pacific and Australian Plates. The Alpine Fault started as part of the break-up of the supercontinent Gondwana, with New Zealand starting to drift away from Antarctica about 80 million years ago.simo That … Transform Boundary – Alpine Fault, South Island, New Zealand. Although the Alpine Fault trace, mylonitisation of the Alpine Schist was Rattenbury [1991] inferred that most of the local mylonitic overprint, however, are all consistent with This molten rock rises to the surface through the thinned crust and is either erupted from volcanoes like Ruapehu, Tongariro and Ngaruhoe or sits within the crust and heats it, and the water it contains, up causing geothermal activity around Taupo and Rotorua. Approximate rupture dates are 1717AD, 1620 AD, 1450 AD, and 1100 AD. However, this study has shown that for faults similar to the Alpine Fault, a fairly regularly repeating earthquake cycle is a realistic foundation on which to base earthquake hazard estimates. 1) form a complex that is probably a genetic unity (Lensen, 1955b, … New Zealand lies at the edge of both the Australian and Pacific tectonic plates. The last time the Alpine Fault did this was in 1717, when it shunted land horizontally by eight metres (26 feet) and uplifted the mountains a couple of metres (6.5 feet). Cancel. This, along with isostaticconstrai… The Alpine Fault is a geological fault, specifically a right-lateral strike-slip fault, that runs almost the entire length of New Zealand’s South Island. The Alpine Fault ruptures—on average—every 330 years with a magnitude 8 earthquake. Alpine Fault identifies earthquakes in the years 1717, 1620, and 1430, with estimated moment magnitudes of 7.9±0.3, 7.6±0.3, and 7.9±0.4, respectively (Sutherland et al., 2007). 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Between 23 and 10 million years ago the western side of the Alpine Fault was moving northeast relative to the eastern side at a rate of between 1-10 cm per year. It runs as a single structure for over 500 km. The Alpine Fault quickly became accepted as a notable feature of the geology of New Zealand, and by 1948 was included on standard geological maps. Keywords: Alpine Fault; fault rocks; friction; permeability; surface rupture. This has resulted in about 450 km of displacement along the Alpine Fault. The Alpine Fault. Differential uplift along the Alpine Fault plate boundary, South Island, New Zealand, since 5 Ma (Sutherland 1995) has exposed a depth section through the Alpine Schist, with the highest grade rocks (garnet-oligoclase zone, amphibolite facies) outcropping within and immediately east of a mylonite zone adjacent to the Alpine Fault. The research also calculates there is about an 82 percent chance that such an earthquake would be magnitude 8 or higher. The Hope fault is thought to represent the primary continuation of the Alpine fault. / Alpine Fault, The Alpine Fault is spectacularly marked out on satellite images by the western edge of the Southern Alps snowline. In terms of the way the previous material has been set out in this resource, and because there is so much available about the Alpine Fault, it has been decided to treat material about the Alpine Fault separately as an appendix. If playback doesn't begin shortly, try restarting your device. Recent research (published in 2012) by GNS Science has extended our knowledge of the Alpine fault earthquake record back through the past 8000 years. The Australian and Pacific Plates generally don’t move smoothly past each other. Video: AF8 The Alpine fault is defined as the 650 km long feature that extends the length of the South Island. 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