Fault line . However, the findings do suggest that seismic activity on the Alpine Fault is more complex than suspected, particularly along its northern reaches where the plate boundary transitions into another fault zone. How many aftershocks have there been, and is this normal? Prof Stirling recently said he wanted to make Otago people aware that there were potentially hazardous earthquake sources that were closer to Dunedin than the Alpine Fault. The most likely source of tsunami events which may affect Otago’s eastern coastline are large earthquakes (magnitude > 8), which cause a vertical displacement of the seabed along a fault line. The four most recent earthquakes uncovered by the researchers at the site range in dates from 1084 to 1848. This means, the Alpine Fault is late in its seismic cycle … Your feedback will go directly to Science X editors. 5.0 earthquakes and aftershocks in 1997, which occurred close to the central part of the Alpine fault. It is therefore prudent to consider the Akatore Fault as potentially the most likely source of future strong ground shaking for Dunedin.". part may be reproduced without the written permission. The fault is not explicitly … Current work and … Your opinions are important to us. Prof Stirling warns these effects would be "much worse" for Dunedin than a major Alpine Fault quake. Why is the CO2 level lower in my house than outside? The effects will be amplified in South Island mountainous regions and high country where enormous damage can occur … 5(b)). ... Large earthquakes are less common along the central Alpine Fault, ... Dunedin Otago 4.9 12 km 45.97°S 170.52°E Widespread chimney damage in southern suburbs of Dunedin 5 November 1974 Opunake Taranaki 6.0 5.4: 12 km Evidence is growing the South Island's Alpine Fault, capable of devastating earthquakes of magnitude 8 and above, ruptures more frequently than previously believed. The Akatore Fault is close (20km or less)," he says. We provide bus services in Queenstown and Dunedin to help you get to where you need to go. A smaller seismic event on a local offshore fault could also produce tsunami events along sections of Otago’s coast. "Because of the recurrence times of earthquakes though, you obviously have to wait a long time to see the effects of such fault behavior. ... (including Alpine Fault) are going to be taken into consideration in future scope of this study. Mw7.0 Greek islands off the coast of western Turkey, Meridional Heat Transfer - Ocean and Atmosphere, Today's Climate Change and the Permian-Triassic Boundary, Science X Daily and the Weekly Email Newsletter are free features that allow you to receive your favorite sci-tech news updates in your email inbox. It last ruptured in 1717 and there is a big earthquake, on average, about every 300 years, but the times vary so there is thought to be about a 30% risk of the next ‘Big One’ in the next fifty years. Copyright © 2020 MediaWorks TV - All Rights Reserved, By subscribing you agree to our Terms of Access and Privacy Policy. Get weekly and/or daily updates delivered to your inbox. "We do think that it's in a heightened phase of activity, and it's hard to say how long that will last. Professor Waters said the Akatore Fault remained a bigger threat to Dunedin than the Alpine Fault, which runs the length of the South Island. "We are calculating peak ground accelerations of >0.5g for Dunedin. The Alpine Fault runs for about 600km along the west of the Southern Alps. The rupture will produce one of the biggest earthquakes since European settlement of New Zealand, and it will have a major impact on the lives of many people. Your email address is used only to let the recipient know who sent the email. "I would not expect the Alpine Fault to produce damaging ground shaking in Dunedin as it's too far away from the city. In the south of the country, eastward-directed subduction occurs beneath Fiordland on the Puysegur Subduction Zone. googletag.cmd.push(function() { googletag.display('div-gpt-ad-1449240174198-2'); }); The findings published in the Bulletin of the Seismological Society of America suggest that some places along the fault, particularly around the towns of Hokitika and Greymouth, could experience strong ground shaking from Alpine fault earthquakes more often than previously thought. The 3.24am quake was 5km deep and reported by more than 600 people around Queenstown and Wanaka. The fault, which runs about 600km up the western side of the South Island between Milford Sound and Marlborough, poses one of the biggest natural threats to New Zealand - especially the West Coast, Canterbury and Otago. Kirilova, Martina Atanasova. "The San Andreas Fault, being on the opposite side of the Pacific plate, it is like our distant brother or whanau—family," said Langridge. Medical research advances and health news, The latest engineering, electronics and technology advances, The most comprehensive sci-tech news coverage on the web. As large earthquakes have not been experienced in the area of interest in the historical and instrumental records, user-specified scenario simulations are of great value. Why we need to worry about an Alpine Fault earthquake! Professor Craw said the old Akatore earthquake would have been similar in magnitude to the 2016 Kaikōura quake, with tens of kilometres of rocky coast affected, and the old shore lifted out of the water, well beyond the reach of the waves. This fault has ruptured four times in the past 900 years, each time producing an earthquake of about magnitude 8. The last such earthquake took place in 1717. 5G and future 6G terahertz absorbed by water vapour = heating? Fortunately this was before the historic settlement of New Zealand. In collaboration with AF8, University of Otago, GNS Science, QuakeCoRE, Emergency Management Otago, and Resilience to Nature's Challenges. The Southern Alps have been uplifted on the fault over the last 12 million years in a series of earthquakes. But new evidence of a 19th century earthquake indicates that in at least one portion of the fault, smaller earthquakes may occur in between such large rupture events. Brendon Bradley, professor in earthquake engineering at the University of Canterbury, has created a computer simulation of the likely impact of a magnitude 8 earthquake on the Alpine Fault. "It has had a heightened state of activity in the geologically recent period after a long period of quiescence," Prof Stirling told Newshub. The best paleoseismic evidence to date suggests the southern and central sections of the Alpine Fault, at the boundary separating the Australian and Pacific tectonic plates, typically rupture during very large full-section earthquakes of magnitude 7.7 or larger. Alpine Fault; Climate; Controlled Source Seismology; Earthquake science; Economic geology; Environmental geology; Geochemistry; Geophysics; Gold; Paleomagnetism; ... now extending the 1D simulations to 2D in order to model the site response from the sediment profiles beneath parts of Dunedin, and from the fault-controlled Taieri sedimentary basin. "The old Akatore earthquake would have been similar in magnitude to the 2016 Kaikoura quake, with tens of kilometres of rocky coast affected, and the old shore lifted out of the water, well beyond the reach of the waves," says Professor Dave Craw. New evidence of a 19th century earthquake on New Zealand's Alpine fault suggests that in at least one portion of the fault, smaller earthquakes may occur in between such large rupture events. Earthquake-induced tsunami. In her talk Dr Orchiston will outline the science behind the Alpine Fault, progress of Project AF8 so far and describe some of the key issues that will be most relevant for Dunedin in the event of an Alpine Fault earthquake. In between earthquakes, the Alpine Fault is locked. The fault runs for about 20km onshore - between about Taieri Mouth and Toko Mouth - and possibly more than 40km offshore. Hear from leading Alpine Fault scientists about the likely impacts of an Alpine Fault earthquake in your area and how we can be better prepared for such an event. "The Akatore Fault and the Titri Fault are very close to the city, and if they had their major earthquakes they would shake the city very, very badly compared with what … This is very strong shaking that would be damaging for Dunedin's old buildings," Prof Stirling told Newshub. You can unsubscribe at any time and we'll never share your details to third parties. After trenching along the fault at the Staples site near the Toaroha River, however, Robert Langridge of GNS Science and colleagues uncovered evidence of a more recent earthquake along the northeastern end of the fault's central portion. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form. Dunedin buses. "By comparison, the Kaikōura Earthquake in 2016 ruptured a total fault length of 200km in the space of about two minutes," said Holden. . The Kaikōura earthquake ... identified on The Humps Fault prior to the earthquake [22], and a recurrence interval of 13,000±8710 years was assigned to the fault [23]. Representatives of fifty organisations from throughout Otago met in Dunedin today to participate in planning for the first week of response to a major Alpine Fault earthquake. The Alpine Fault is a big feature of South Island geography and seismic activity. As the last quakes lifted a large stretch of New Zealand's southeastern coast up by two-three metres, a University of Otago team has been studying the effects on populations of coastal species. Listen: Mike Puru talks with geologist Martha Savage about New Zealand's largest faultline. The most recent earthquake could represent a "partial-section" rupture of only the central portion of the Alpine fault, a rupture of the fault's northern section that continued southwest into the central segment, or even triggered slip from a rupture along the nearby Marlborough Fault System. T he science and impact of an earthquake on the Alpine Fault will be the topic of two workshops in the Mackenzie district next week. or, by Seismological Society of America. We do not guarantee individual replies due to extremely high volume of correspondence. ... Dr Simon Cox, who is a principal scientist at GNS Science in Dunedin, will also speak. "One of the real challenges with the Alpine Fault—because it is so bush-covered—is actually finding sites that have been cleared and therefore can be studied," said Langridge. New evidence for geologically recent earthquakes near Portland, Oregon metro area, River sediment history suggests it was climate change, not Mongol invasion that doomed Transoxania, New constraints on alternative gravity theories that could inform dark matter research, Best of Last Year: The top Phys.org articles of 2020, Large ionized bubble around NGC 5585 X-1 investigated in detail, Magnetically controlled, hydrogel-based smart transformers. A rupture along the full length of the fast-slipping Alpine Fault on New Zealand's South Island poses the largest potential seismic threat to the southern and central parts of the country. Just days after South Island residents were shaken awake by a 5.5 magnitude Alpine Fault quake, University of Otago earthquake expert Professor Mark Stirling warns there's a bigger threat to Dunedin. The alpine fault earthquake will alter tectonic stress distribution, ... What will happen to the earth during the earthquake? The Alpine fault is the Pacific-Australian plate boundary in the South Island of New Zealand. Apart from any fair dealing for the purpose of private study or research, no This is a list of large earthquakes that have occurred in New Zealand. The Alpine Fault is a geological fault that runs almost the entire length of New Zealand's South Island (c. 480 km) and forms the boundary between the Pacific Plate and the Indo-Australian Plate. Neither your address nor the recipient's address will be used for any other purpose. The way that earthquake stresses around faults interact is very complex. A rupture along the full length of the fast-slipping Alpine Fault on New Zealand's South Island poses the largest potential seismic threat to the southern and central parts of the country. Xiaoming Wang, Caroline Holden, William Power, Yaoru Liu, Joshu Mountjoy, Seiche Effects in Lake Tekapo, New Zealand, in an Mw8.2 Alpine Fault Earthquake, Pure and Applied Geophysics, 10.1007/s00024-020-02595-w, (2020). We have currently located 63 aftershocks, with 16 being magnitude 3 and above, this is … A graphic shows an indicative line of the Alpine Fault in relation to Wanaka and Queenstown. But if it happened again, given the population and buildings in the area, we wouldn't be so lucky. Radiocarbon dating places this earthquake between 1813 and 1848. You can be assured our editors closely monitor every feedback sent and will take appropriate actions. It is clear from these results that the … . Prof Davies is in the United Kingdom on sabbatical at present so could not be reached for comment on Monday's earthquake and its impact on the Alpine Fault. This study investigates the potential for seismic seiches in Lake Tekapo, New Zealand, triggered by ground shaking from an Mw8.2 Alpine Fault earthquake. The planning workshop is part of a series being led by Jon Mitchell, Project AF8 Programme Manager, in each of the 6 Civil Defence Emergency Management (CDEM) Group areas across the South Island in preparation for an eventual … Dr. Simon Cox is a Principal Scientist at GNS Science in Dunedin. Recent research (published in 2012) by GNS Science has extended our knowledge of the Alpine fault earthquake record back through the past 8000 years. Langridge said researchers in California and New Zealand have a long history of earthquake science collaboration and are learning from each other about the treatment of active faults and fault segmentation for seismic hazard models. This was "clearly devastating" for coastal species like kelp and shellfish, which were left literally high and dry. However, most of the motion on the fault is strike-slip (side to side), with the Tasman district and West Coast … Dr Cox and Prof Bradley are speaking only at the Mackenzie events. The Magnitude-8.0 or greater earthquakes were expected on the Alpine Fault approximately every 300 to 500 years. "The ancient Akatore uplift was big enough to eliminate entire populations of intertidal species," the researchers say. These effects are covered in other papers within this special issue. ... New Zealand’s Alpine Fault is a major crustal-scale structure that accommodates around 75% of relative Australian-Pacific plate motion. Dr Caroline Orchiston from the Centre of Sustainability, University of Otago, outlines a new initiative called Project AF8, a multi-agency approach to response and resilience planning for a magnitude 8 earthquake in the South Island. Credits: Image: Getty; Audio: Magic Talk. The fault's last quakes were between 1280 years and 760 years ago and moved the ground up to two metres vertically. "By comparison, the Kaikōura Earthquake in 2016 ruptured a total fault length of 200km in the space of about two minutes," said Holden. "The Akatore Fault is the most active fault in Otago, and is the highest hazard fault for Dunedin," he told Newshub. Synthetic ground motions are used as a forcing boundary to drive lake water motions by further developing a tsunami simulation model—COMCOT—and coupling it with earthquake simulation model outputs. In order to prevent massive damage to Dunedin, Prof Stirling urges authorities to put in place effective hazard and risk communication plans to warn the public, and emergency management plans that deal with an Akatore Fault earthquake scenario. Thank you for taking your time to send in your valued opinion to Science X editors. By using our site, you acknowledge that you have read and understand our Privacy Policy 74 ... on the Alpine Fault [7-11]. ... which occurred close to the central part of the Alpine … At this stage we are unsure of how the Alpine Fault may have been affected, though it is likely that any effect would be very small. The roadshow is supported by the Ministry of Civil Defence and Emergency Management, the six South … The Alpine Fault has a high probability (estimated at 30%) of rupturing in the next 50 years. The next quake is predicted to be around magnitude 7-7.4. The Alpine Fault is sometimes compared with California's San Andreas Fault, being another fast-moving strike slip fault near a plate boundary. This active transform fault ruptures in a large earthquake every 291 ± 23 years, most recently in 1717. and Terms of Use. Get all the information you need to get around Dunedin. Dunedin’s earthquake hazard was higher than Auckland’s. ... response planning and community engagement designed to build a collective resilience and preparedness to the next … Only earthquakes with a magnitude of 6.0 or greater are listed, except for a few that had a moderate impact. The content is provided for information purposes only. "One of the outcomes of this study is that you should expect a shorter recurrence interval of strong shaking at fault section ends," Langridge said. Do equations for groundwater flow refer to water density? Therefore, almost all local trips and inter-district trips from these three districts will be cancelled. A new model has simulated the disruption a major Alpine Fault earthquake would have on the South Island's transport network - cutting off the West Coast for at least a week. Scientists are now studying whether we should expect another Akatore Fault earthquake in the immediate future. This document is subject to copyright. The project goal is to improve the South Island's collective response capability to deal with a future magnitude 8 earthquake. The next Alpine Fault earthquake would likely also be a long-duration event – unzipping the crust for as much as three minutes - because of the sheer length of the fault. PHOTO: PROJECTAF8.CO.NZ “What we know about the Alpine Fault is that it tends to produce big earthquakes, roughly every 300 years,” Dr Orchiston said. Due to the Alpine fault earthquake, the two main highways connecting the east of the South Island to the west (SH7 and SH73) and most parts of SH6 will be completely blocked one day post-disaster causing three Districts (Buller, Westland, and Grey) on the west coast to be isolated (Fig. The events were confirmed by data collected from other nearby trenching sites and from geological deposits called turbidites, which are sediments shaken loose into a body of water by seismic activity, in lakes along the central section of the Alpine fault. A big quake on the Alpine Fault could block South Island highways in more than 120 places and leave 10,000 people cut off, new research has estimated. An Alpine Fault earthquake will be felt by every South Islander and likely many North Islanders, too. This site uses cookies to assist with navigation, analyse your use of our services, and provide content from third parties. Our modelling results … Has this earthquake had any impact on the Alpine Fault? Click here to sign in with Langridge and colleagues said that there isn't enough evidence yet to favor one of these scenarios over the others. ... so for us … "Once we started working there [at the Staples site] the story really grew in large part because of the richness of dateable organic material in the trenches.". ", "That's why paleoseismology is a vital tool in understanding faults," he added, "because otherwise we'd have only short insights into the past.". This study analyzes 195 earthquakes recorded during the 6 month duration of the Southern Alps Passive Seismic Experiment (SAPSE) in 1995/1996 and two M₁. His work involves: fault and earthquake research in the South Island; the mapping of rock avalanches, earthquake-induced landslides and alluvial fan flooding hazards; and building a digital geological map dataset of Antarctica. "There is no reason to assume that the heightened activity has died off, as it's been less than 1000 years since the last event. The effects of graphite and porosity on the mechanics of the Alpine Fault, New Zealand. The Canterbury Plains could suffer more damage in an Alpine Fault quake than some areas closer to the fault, say researchers - and it is not alone. Approximate rupture dates are 1717AD, 1620 AD, 1450 AD, and 1100 AD. GeoNet has issued a warning following a magnitude 5.5 quake this morning near Milford Sound. PhD funded by QuakeCoRE to undertake 3d shear wave velocity modelling for ground motion simulations in Dunedin and Mosgiel. Just days after South Island residents were shaken awake by a 5.5 magnitude Alpine Fault quake, University of Otago earthquake expert Professor Mark Stirling warns there's a bigger threat to Dunedin. Only at the Mackenzie events of these scenarios over the others wave velocity modelling for ground motion simulations Dunedin. Is clear from these three districts will be cancelled used for any other purpose ground motion simulations in,! Fault is not explicitly … the Alpine Fault [ 7-11 ] future scope of this study third parties shaking would. You for taking your time to send in your valued opinion to Science X editors ancient Akatore was... 500 years last 12 million years in a series of earthquakes provide content from parties! About New Zealand 's largest faultline the project goal is to improve the South Island 's collective response capability deal. 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