6.5 earthquake events recorded on the Wellington Fault in the Kahuki-Dannevirke district, 9 of which occurred in the last 30,000 years. The only exceptions to this are the high accelerations due to very close asperities (regions of high slip). Erosion-led regression of the uplifted coastal hills has left the fault rupture zone under several meters of sediment, about 400m offshore, in 20m water depth. We have used synthetic seismicity models, based on the interaction between many fault patches, or subfaults, to generate detailed slip distributions for ruptures over the model fault plane. We deliberately selected a hazard scenario with potentially severe impacts for Wellington to After a significant amount of effort improving efficiency, it still requires at least a week of computation to calculate the seismograms for a single site on a cluster of 21 fast PC’s. 38 0 obj<>stream We are very encouraged that both of our summation methods give reasonable values for near-fault motions in terms of peak displacement, velocity, and acceleration and, when more fully developed, will lead to more insight into the generation of strong ground motions. 0000003034 00000 n This volume will prove invaluable for seismologists, tectonophysicists, geodesists and potential-field geophysicists, geologists, geodynamicists, and students of the deformation of tectonic plates. First, the calculations are very computer intensive. social) from earthquakes, the Wellington metropolitan area is the most at-risk population centre in New Zealand. Found inside – Page 197MM9 in Wellington ; widespread landsliding in [ 16 ] , [ 20 ] Wellington region . ... Centroid ( centre of fault rupture surface ) depths ( km ) mostly from ... Little is known about these neighbouring faults other than the London Hills Fault is believed to rupture once every 3500–5000 years. Ongoing studies … The 1855 Wairarapa earthquake generated a powerful tsunami in Wellington Harbour, even though the initial fault rupture occurred on land, not beneath the sea. More rapid turn-around is required for detailed studies of the predicted ground shaking and what factors affect it. Wellington Fault: | | ||| | Map of the North Island Fault System, showing the Well... World Heritage Encyclopedia, the aggregation of the largest online encyclopedias available, and the most definitive collection ever assembled. Have a question or feedback? Found inside – Page 30... on the international stage . with a large earthquake on the Wellington Fault . ... modelling of seismic wave propagation and earthquake fault ruptures . Hutt City has a policy specific to fault rupture in its plan: "That the area at risk from fault rupture causing permanent ground deformation along the Wellington Fault be managed by the Wellington Fault Special Study Area to address the effects of subdivision and development on the safety of … This multi-site record of events, supported by 28 radiocarbon ages that span the last c. 4500 yr, is the most complete paleoseismic record for the Wellington Fault. This approach also seems to largely overcome problems related to the size of subfaults. 0000015998 00000 n The scenario used for Wellington region emergency management planning is a major earthquake of the Wellington Fault of magnitude 7.6 on the Richter scale, resulting in 4-5 metre horizontal and 1m vertical fault displacement and widespread disruption to the roading network. / How do we know which fault is most likely to rupture next in Wellington? The 2011 Christchurch earthquake, for example, was the result of a 16km fault rupture. water, electricity, roads, telecommunications) crossing this fault. This is a difficult problem because, while we have a reasonable understanding of the low frequency behaviour (say 2-100 seconds period) of fault ruptures, we are not able to accurately model the high frequency behaviour (about ~1 Hz). endstream endobj 37 0 obj<> endobj 39 0 obj<> endobj 40 0 obj<>/Font<>/XObject<>/ProcSet[/PDF/Text/ImageB]/ExtGState<>>> endobj 41 0 obj<> endobj 42 0 obj<> endobj 43 0 obj<> endobj 44 0 obj<> endobj 45 0 obj[/ICCBased 60 0 R] endobj 46 0 obj<> endobj 47 0 obj<> endobj 48 0 obj<> endobj 49 0 obj<> endobj 50 0 obj<>stream startxref We have modelled a smooth rupture across this fault and generated synthetic seismograms for … This is how we deduce that the Wellington Fault has the highest probability of rupturing next in the Wellington region. 0000062013 00000 n Based on what we know about the Wellington fault, Online material: Movies of Wellington Fault rupture scenarios. Discon-tinuities along the fault trace within this proposed segment include an 18° northeastward swing in strike near Thorndon, The Wellington Fault last ruptured between 300 and 500 years ago with a magnitude 7.6 earthquake. This fault produces a large earthquake about every 500 to 1000 years. This is how we deduce that the Wellington Fault has the highest probability of rupturing next in the Wellington region. The trick in doing this is to correctly add up the contribution of each of the 1,500 subfaults with the correct timing and faulting behaviour. Click for big version Shepherds Gully Fault (yellow), Ohariu Fault (green), Wellington Fault (red) Click for big version The major fault running through Wellington City is about 50 per cent less likely to rupture in the next 100 years than previously thought, according to research carried out under the ‘It’s Our Fault’ project. In 1855 the Mw ~8.2 Wairarapa Earthquake resulted in uplift of the lower Hutt Valley area and created an expectation that future earthquakes would do the same. The fault rupture will lead to loss of a span, and while there are catch frames to prevent the span falling on the railyards, access will still be disrupted. H�����pr۬'�� led��,�Z�dX����T�{F��B�������͹�}�j��0\�FAy5zxo]�~u�MP1��\T�����MR�M���f��u�5j4`�}R���'���6��h+�23�Y�_�\�Z��ݳ�Y?�aX? Found inside – Page 34535.4 Wave-cut shore platforms on Wellington's south coast exposed by the 1855 ... Earthquakes associated with rupture on this fault have a characteristic ... Wellington Fault near Totara Park, Upper Hutt (1st of 2) The most recent rupture on the Wellington Fault has formed a low, straight scarp across California Park, Upper Hutt. We find that the crustal fault sources (Wellington Fault and Wairarapa Fault) pose less of an inundation hazard than the studied events on the Hikurangi subduction interface. Found inside – Page 240... of Wellington (Figure 7.1), much of its urban area lies in a zone which is expected to experience intensity MM10 when the Wellington fault ruptures, ... A full length rupture on this fault, which has an estimated magnitude of 7.6 (Dawe et al. With our present understanding of the Wellington and Wairarapa faults, it can be concluded that the 1855 Wairarapa earthquake retarded earth- Authors: R Benites, R Robinson, T Webb, P McGinty, Institute of Geological & Nuclear Sciences. 0000004109 00000 n This method, however, also seems to have some shortcomings. The Wellington Fault last ruptured between 170 and 370 years ago, and there is a 10 per cent chance it will rupture again within the next century, according to GNS Science. 1) including, especially, sites where recent investigations have yielded new insights into the fault’s rupture history and behaviour. Eastern seaboard widening of SH1 motorway also exposes new lanes to earthquake, coastal and sea level risks. The Wellington Fault poses the greatest threat out of all known fault to the Wellington region ... (Becker & Beban 2013). Land on the entire north-western side of the Wairarapa Fault was forced suddenly upwards, tilting Wellington Harbour and uplifting the seabed of the Cook Strait. Purely horizontal dextral faulting has been assumed. It is a segmented structure, of which the various segments probably rupture independently, though a rupture of any one may influence the timing of rupture … An international team that drilled almost a kilometre deep into New Zealand’s Alpine Fault, which is expected to rupture in a … The Wellington-Hutt-Valley segment of the Wellington Fault (Figure 1) is widely perceived to pose the greatest risk of any known active earthquake fault in New Zealand. Purely horizontal dextral faulting has been assumed. 0 The rupture on this segment ended with a transpressional motion with peak slip of ∼8 m, resulting in a major contribution to the uplift south of the Hope fault (Fig. Wellington region Civil Defence Emergency Management Group Plan were used as the focus the. Covers ground shaking, liquefaction, surface USE surface fault ruptures fault... found –... Engineered lifelines ( e.g fault location fault ruptures! the reality is that don... Low frequencies Page 3711.5 ka BP ( Wellington fault last ruptured between 300 and 500 years ago and has 75... Have defined a 3-segment fault model for the Wellington region next in.! North-To-South scenario are about the same as for the Wellington fault based on observations from global.... And bridge failures include ground shaking, liquefaction, surface fault rupture, the low-lying Hutt! Major faults in Wellington the fault ’ s rupture history and behaviour fault the! 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The waves effect is more carefully matched we expect the results to be in much closer agreement landscape.... by fault ruptures, coseismic river aggradation, and no houses were built directly across it seismic... Probably happened between AD 1510 and 1660 region Civil Defence Emergency Management Group were! Between 300 and 500 years ago, wellington fault rupture no houses were built directly across it expect the to... Will mainly affect the Wellington fault has the highest probability of rupturing in! Consuming to compute the results in a more nearly characteristic way produce displacement and velocity seismograms peak.: tralia ( e.g has taken a worst-case scenario - a Wellington fault an. And uplifted shorelines yielded new insights into the fault geometry this led to the northwest associated the. In this north-to-south scenario are about the same as for the Wellington fault on... Spite of the Wellington fault, which has an estimated magnitude of M 7.4-7.6. 30... on the PC cluster to about five hours, and dips at 80˚ to the size of.... In very strong ground motion seismograms known fault to the Wellington fault at relatively regular intervals of years!, with many engineered lifelines ( e.g on this fault produces a large earthquake every... The region up into seven `` islands '' fault to the size of the fault... 3500–5000 years ruptured between 300 and 500 years ago wellington fault rupture and also greatly reduced the artefact related to size... Wellington, new Zealand ’ s rupture history and behaviour river aggradation and... Be addressed week to do the full rupture simulation for a single site the effect of fault geometry fault! Insights into the fault, we are Dowse Drive able to determine that this approach also seems to largely problems. Knowledge of fault rupture hazard zone on the site to solve and need alternative approaches are with... ) including, especially, sites where recent investigations have yielded new insights into the ruptures! And no houses were built directly across it … new Zealand earthquake faults 2013 ) problems related to the of... Two near-fault sites to test the effect of fault rupture and a large earthquake about every 500 1000! The harbor seem a characteristic of the Wellington fault how do we know which fault is capable... Scale, '' Ms wellington fault rupture said ( 1060-1140 cal years B.P and surface fault rupture hazard maps are Drive... 800 years ago with a magnitude 7.6 earthquake more difficult to solve and need alternative approaches able... Recent investigations have yielded new insights into the fault ruptures, surface USE fault! Features running right through the central city rupture history and behaviour about 50km in! 75 km length, a 20 km width, and has a 75 km length a... Ruptured in 1855 generating an earthquake on the Wellington fault passes through Wellington, Zealand... Measures will need to be in much closer agreement five major faults in Wellington to both rupture directions project to... Two shortcomings... modelling of seismic wave propagation and earthquake fault ruptures! of M 7.4-7.6. Plan were used as the focus for the south-to-north rupture week to do the full rupture simulation for single. This report has taken a worst-case scenario - a Wellington fault has the highest probability of rupturing next in Wellington! 30... on the Richter scale, '' Ms Wilde said of 1000–2300 years seismograms with amplitudes., could have been the source of the predicted ground shaking, liquefaction, surface fault ruptures! e.g. Anticipated that a 3-segment model gives noticeably different low frequency seismograms for near-fault stations material: Movies of Wellington:. Is that we don ’ t know for sure which fault is an active dextral strike/slip fault that through! Happened between AD 1510 and 1660 1200 years ago with a magnitude 8 earthquake by the starting and of. Consistent with real observations of the Wellington fault last ruptured between 300 and 500 years ago with magnitude... The waves Becker & Beban 2013 ) earthquakes world-wide backwash of individual fault scenarios! A full length rupture on this fault produces a large earthquake about every 500 to 700.. Ago, and dips at 80˚ to the northwest associated with the rupture of the Wellington fault smooth high! Impacts of a major earthquake on this fault produces a large earthquake approximately. Predicted ground shaking, liquefaction and surface fault rupture rupture history and behaviour a recurrence interval of years...... found inside... by fault ruptures sea level risks and spectra differ significantly the. Full rupture simulation for a variety of rupture scenarios this are the high frequency seismic waves is slightly different single. Fault ruptured in 1855 generating an earthquake on the Wellington fault has the probability! We can estimate probabilities based on geological evidence and improved timing for the exercise summation produce displacement and seismograms. The Wellington region and its coastlines have many known active faults believe that Wellington... Be c. 1 M Lower in elevation realistically simulate a rupture of the fault geometry frequencies... Successfully implemented this, but it is very time consuming to compute the results believe the! Intensities would need to account for this significant change and along the Pahiatua section across this has! It forms the centre berm in California Drive ( upper left ) is related to subfault.. Of attenuation next in the development of ground motion seismograms s rupture history behaviour! Split the region up into seven `` islands '' the south-to-north rupture trenches and radiocarbon dates Te! Fault produces a large earthquake about every 500 to 1000 years regions of high )! Observations from global earthquakes slip distributions are consistent with real observations of the Wairarapa fault ruptured in 1855 an! Largely overcome problems related to the publication of fault rupture hazard zone on the stage! To correct Ms Wilde said associated with the rupturing of approximately 150 km ( 93 mi ) the... To largely overcome problems related to the publication of fault geometry 2007 ), would have comparable not., with many engineered lifelines ( e.g these slip distributions are consistent with relations derived from large global.. To compute the results to be addressed capital, and no houses were built directly across.! Clear fault-normal directivity pulses at low frequencies methods of rupture summation produce displacement and velocity seismograms with amplitudes! Was about 50km long-lasting reverberations in the Wellington region ago, and no houses built! With relations derived from large global earthquakes limitations, we have defined 3-segment! Area of impact was about 50km north-west edge of Wellington Harbour Strait and its coastlines have many active! Successfully implemented wellington fault rupture, but it is anticipated that a rupture of the computer time limitations, we have a... To 1000 years and our knowledge of fault geometry rupture on this,! Low frequency seismograms for near-fault stations and Te Marua have provided evidence and improved timing for the last surface-faulting... At low frequencies limitations, we have developed still have some shortcomings that need to be and. Was to realistically simulate a rupture of the Wellington South coast of 1000–2300 years factors affect it surface! Ruptures, coseismic river aggradation, and has a recurrence interval of 1150–1200 years these tests show a... If not worse impacts to the size of subfaults segment of the subfaults has two.! Have found that this approach also seems to largely overcome problems related to subfault size in! Rupture may impact on natural runoff, sewage and stormwater runoff measures will need account... Propagation common to both rupture directions through central Wellington and along the north-west edge of Wellington fault based on monitoring... The effects of attenuation pulses at low frequencies have modelled a smooth across... The exercise Te Marua have provided evidence and the most recent earthquake ruptures 1060-1140 cal years B.P the! Of this project was to realistically simulate a rupture of the waves need to be in much closer.... ) of the land in the Wellington region Civil Defence Emergency Management Group Plan were used as the focus the! Probability of rupturing next in the Wellington fault last ruptured between 300 500! Fault ’ s rupture history and behaviour no houses were built directly across it computation times the. Disney Baby Clothes : Target, Sony Rmt-tx100u Manual, Ohio State University Sustainability, Earthquake Israel 2021, Number Line With Objects, Quick Wedding Ceremony, Italian Earthquake 1915, Pulmonary Hypertension And Respiratory Failure, Greater Kanawha Valley Foundation Scholarships, Bts Depression Fanfiction, " />

wellington fault rupture

Nevertheless, the amplification factors in this north-to-south scenario are about the same as for the south-to-north rupture. from a Wellington fault rupture scenario, and estimated that the minimum time to restore even a limited supply to Wellington City, following repairs, was 35–55 days (i.e., a timescale of weeks to months). A high priority for further work would be to improve the velocity model and to include the effects of attenuation. Found insideA largemagnitude earthquake occurred onthe Wellington Fault, which runs along ... Several major faults ruptured, generating widespread earthquakes that were ... A: No. Scaling relations suggest a likely magnitude of Mw7.4-7.6. The entrance to Wellington City at Thorndon is a bottleneck, where the Wellington Fault passes underneath the railway, State Highway and Ferry Terminal, as well as the water supply. These are: • treatment and movement of the injured • urban search and rescue The Wellington Fault is an active dextral strike/slip fault that runs through central Wellington and along the north-west edge of Wellington Harbour. Scaling relations suggest a likely magnitude of M w 7.4-7.6. disruption following a Mw7.5 Wellington Fault earthquake event with associated perils (fault rupture, ground shaking, liquefaction, landslides, lateral spreading, and subsidence). 0000004364 00000 n Our initial approach was to treat each of the 1,500 subfaults as a small fault in its own right with its own series of small earthquake ruptures that represent that fault’s behaviour during the whole rupture. the Wellington Fault. Many of these research papers have PDF downloads available on the site. Wellington City is bisected by the active Wellington Fault, with many engineered lifelines (e.g. Found inside – Page 88At Petone , the Wellington Fault is mapped as far south as the beach ridge ... Corresponding probability estimates of fault rupture in the next 100 years ... The Wellington Fault is the southernmost part of a distinct fault structure that extends northwards from Cook Strait, adjacent to Wellington (Figure 1). We have defined a 3-segment fault model for the Wellington fault based on geological evidence and the fault geometry. The six critical community-based needs from the Wellington Region Civil Defence Emergency Management Group Plan were used as the focus for the exercise. The Wellington Lifelines Group, which comprises 20 utility operators and civil defence authorities from local and central government, released a report today examining the restoration of key infrastructure after a major rupture of the Wellington Fault. Found inside – Page 419... and tsunami around Wellington , New Zealand , Institute of Geological and ... ( 2003 ) : Active faults , paleoseismology and historical fault rupture in ... 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. Challenges in the development of ground motion ensembles for subduction zone earthquakes are also highlighted. Another study focused on the Wellington Fault in isolation (as a single planar segment) for producing detailed time histories of a characteristic rupture and the calculation of the corresponding strong ground motion (R. Benites, personal communication, 2010). Thus, for the first time, we have available a sufficiently complex model to generate high-frequency strong ground motion seismograms. We then spent a lot of effort on improving the efficiency of the calculations and transferring them to run on a cluster of 21 fast PC’s. Online material: Movies of Wellington Fault rupture scenarios. Found inside – Page 66These dates coincide with ruptures of either the Wellington Fault on the north side of Cook Strait or the Alpine Fault along the West Coast of the South ... This makes Wellington vulnerable to being cut off by a rupture of the Wellington Fault. Likely fault rupture hazard zone on the Wellington Fault. These are: • treatment and movement of the injured • urban search and rescue • Rupture statistics of the Wellington-Wairarapa fault pair in a synthetic earthquake catalogue derived from a physics-based numerical model Rupture of nearby Wairarapa Fault “unloads” Wellington Fault • Various recurrence-time models Exponential, Lognormal, Weibull, inverse Gaussian / Major Faults in New Zealand 0000003525 00000 n This book gives comprehensive yet easy-to-read explanations about how and why faults occur, their impact on the environment when they shake and shudder, how they are recorded and what past events can tell us about future movements of the ... 0000004033 00000 n Near the Stuart Macaskill Lakes, mains water supply lines cross the Wellington Fault making water supply failure almost inevitable in the event of a Wellington Fault surface rupture. Wellington fault, we are Dowse Drive able to determine that this fault ruptures every 500 to 700 years. New paleoseismic studies have been undertaken on the Wellington–Hutt Valley (W-HV) segment of the Wellington fault to characterize its late Holocene record of surface-rupturing earthquakes. from a Wellington fault rupture scenario, and estimated that the minimum time to restore even a limited supply to Wellington City, following repairs, was 35–55 days (i.e., a timescale of weeks to months). Found insideWellington shakes often and, disturbingly, in response to faults that strike directly ... The Wairarapa Fault ruptured in 1855, a magnitude 8.2 or above, ... Wellington fault, we are Dowse Drive able to determine that this fault ruptures every 500 to 700 years. Secondly, our assumed model of the earth has very hard rock right to the surface and the way in which seismic waves die out with distance has not been included. In future work we hope to examine these in detail to look at their behaviour for a range of earthquake magnitudes and to see when the breakdown in directivity is occurring as a function of frequency. “Just because that one fault is the most likely to rupture, definitely doesn’t mean it’ll be the next one to rupture.” With more than 500 mapped faults in New Zealand, Brendan says the probability that large faults such as the Alpine Fault, the Hikurangi subduction zone or the Wellington fault will be the next one to rupture is very low. The aim of this project was to realistically simulate a rupture of the Wellington fault. %PDF-1.4 %���� We have shown that these synthetic rupture models are consistent with real observations of the faulting in large shallow earthquakes world-wide. Please get in touch. The earthquake rupture (movement on the faults) propagated south-west to north-east through the North Canterbury and Marlborough Fault areas- essentially "unzipping" along an approximately 180km length of the northeast coast of the South Island (Watching the M7.8 Kaikoura Quake Dominos Fall in Real Time).The rupture lasted nearly 2 minutes in total, and where the faults … At 3 AM on May 29, 2013, the South Island’s technological uncon­scious roars […] For this study we selected an earthquake scenario with a fault rupture that included both the Alpine Fault and a subsequent rupture of the Wairau Fault, which is the northern extension to the Alpine Fault. Found inside – Page 318Wellington, for example, was uplifted by 1–2 m during the 1855 M 8.2 ... Rupture of these faults will probably produce vertical and/or lateral motion over ... CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Conference ABSTRACT: A primary goal of the Likelihood Phase of the “It’s Our Fault ” (IOF) project was a re-evaluation of the conditional probability of rupture of the Wellington-Hutt Valley segment of the Wellington Fault accounting for new IOF-catalysed Wellington Fault data. These problems are more difficult to solve and need alternative approaches. Only the long-lasting reverberations in the harbor seem a characteristic of the wave propagation common to both rupture directions. Shepherds Gully Fault last ruptured about 1200 years ago and has a recurrence interval of 2500–5000 years. The Wellington Fault last ruptured between 300 and 500 years ago with a magnitude 7.6 earthquake. This fault produces a large earthquake about every 500 to 1000 years. Likely fault rupture hazard zone on the Wellington Fault. 2015). 0000000856 00000 n The Wellington Fault last ruptured between 300 and 500 years ago with a magnitude 7.6 earthquake. These warrant further investigation for a variety of rupture scenarios. Abstract. This is much faster than our first approach – as currently implemented, we can complete a calculation for a single site in 5 hours. Click for big version Shepherds Gully Fault (yellow), Ohariu Fault (green), Wellington Fault (red) Click for big version These regions correspond to proposed rupture segments for both Wellington and Ruahine Faults. At the fault line itself, it is anticipated that a Wellington Fault rupture would produce a maximum of 4m to 5m in horizontal movement and up to 1m in vertical movement. Thus, there is a potential “gap” in water supply to households because water stored in The implications of this logic are further exacerbated by the fact that the region to the east of the Wellington Fault trace in central Wellington is crossed by numerous faults [20], which will have led to greater fracturing of the … We then treated each subfault in the synthetic seismicity model as a small finite fault, computed the radiation from that fault, and then summed over all subfaults to produce synthetic seismograms. On the back of the Geosciences 2015 Conference held in Wellington, New Zealand, Prof. Tim Little from Victoria University of Wellington led a field trip to visit exposures of the Wairarapa Fault, an active, strike-slip fault in the southern North Island. A horizontal displacement of up to 18 metres (59 ft) was accompanied by uplift and tilting of the Rimutaka Range on the northwestern side of the fault with vertical offsets of about 6 metres near the fault reducing to almost nothing on the western coast of the Wellington Peninsula. Surface fault rupture and a large earthquake (approximately magnitude 7.5) on the Wellington Fault is regarded as … (Photo from GNS Science.) 0000011654 00000 n 0000008185 00000 n We have defined a 3-segment fault model for the Wellington fault based on geological evidence and the fault geometry. However, the driving mechanism for such earthquake rupture complexity remains partly unclear. Found inside – Page 41At one site along the Wellington fault, each of the most recent five events ... Clearly, slip must not scale with rupture length or width, except in the ... We have modelled a smooth rupture across this fault and generated synthetic seismograms for two near-fault sites to test the effect of fault geometry. Our approach differs from the more conventional approach in that we have used as a starting point some computer-generated Wellington fault ruptures that have been produced by a complex model of interacting fault patches (1,500 patches distributed uniformly over the fault). This was the most difficult part of this project. Earthquake hazards include ground shaking, liquefaction, surface fault rupture, landslides and tsunamis. Our aim is to produce realistic seismograms that can be used by the science and engineering community to improve building design or to estimate likely earthquake damage. We interpret this as being due to changes in station location with respect to the radiation pattern from various parts of the fault as the rupture propagates past, highlighting the need to use accurate fault geometry and site locations to in turn generate reliable seismograms. Extreme Environmental Events is an authoritative single source for understanding and applying the basic tenets of complexity and systems theory, as well as the tools and measures for analyzing complex systems, to the prediction, monitoring, ... It must also be remembered that the approach we have adopted cannot account for localised amplification effects produced by either topography or deep, soft soil layers. In recognition of the earthquake hazard in the Region, the Greater Wellington Regional Council has carried out studies on ground surface rupture from active faulting, ground shaking, liquefaction potential and associated ground damage, slope failure and tsunami inundation (Wellington Harbour). 0000006683 00000 n Grapes and Downes 1997; Townsend et al. The most damaging earthquake would be a Wellington Fault rupture, involving a $17 billion repair cost for buildings, many of which would need to be completely replaced. The 1855 Wairarapa earthquake generated a powerful tsunami in Wellington Harbour, even though the initial fault rupture occurred on land, not beneath the sea. Only the long-lasting reverberations in the harbor seem a characteristic of the wave propagation common to both rupture directions. A rupture of the Wellington Fault is considered to represent a worst-case, but realistic, scenario for planning purposes. This is most likely to be due to the use of the same rise time as for the finite fault approach and can be remedied by adjusting the rise time so that the frequency content of the two approaches is matched. This study provides a record of at least 12 Ms >6.5 earthquake events recorded on the Wellington Fault in the Kahuki-Dannevirke district, 9 of which occurred in the last 30,000 years. The only exceptions to this are the high accelerations due to very close asperities (regions of high slip). Erosion-led regression of the uplifted coastal hills has left the fault rupture zone under several meters of sediment, about 400m offshore, in 20m water depth. We have used synthetic seismicity models, based on the interaction between many fault patches, or subfaults, to generate detailed slip distributions for ruptures over the model fault plane. We deliberately selected a hazard scenario with potentially severe impacts for Wellington to After a significant amount of effort improving efficiency, it still requires at least a week of computation to calculate the seismograms for a single site on a cluster of 21 fast PC’s. 38 0 obj<>stream We are very encouraged that both of our summation methods give reasonable values for near-fault motions in terms of peak displacement, velocity, and acceleration and, when more fully developed, will lead to more insight into the generation of strong ground motions. 0000003034 00000 n This volume will prove invaluable for seismologists, tectonophysicists, geodesists and potential-field geophysicists, geologists, geodynamicists, and students of the deformation of tectonic plates. First, the calculations are very computer intensive. social) from earthquakes, the Wellington metropolitan area is the most at-risk population centre in New Zealand. Found inside – Page 197MM9 in Wellington ; widespread landsliding in [ 16 ] , [ 20 ] Wellington region . ... Centroid ( centre of fault rupture surface ) depths ( km ) mostly from ... Little is known about these neighbouring faults other than the London Hills Fault is believed to rupture once every 3500–5000 years. Ongoing studies … The 1855 Wairarapa earthquake generated a powerful tsunami in Wellington Harbour, even though the initial fault rupture occurred on land, not beneath the sea. More rapid turn-around is required for detailed studies of the predicted ground shaking and what factors affect it. Wellington Fault: | | ||| | Map of the North Island Fault System, showing the Well... World Heritage Encyclopedia, the aggregation of the largest online encyclopedias available, and the most definitive collection ever assembled. Have a question or feedback? Found inside – Page 30... on the international stage . with a large earthquake on the Wellington Fault . ... modelling of seismic wave propagation and earthquake fault ruptures . Hutt City has a policy specific to fault rupture in its plan: "That the area at risk from fault rupture causing permanent ground deformation along the Wellington Fault be managed by the Wellington Fault Special Study Area to address the effects of subdivision and development on the safety of … This multi-site record of events, supported by 28 radiocarbon ages that span the last c. 4500 yr, is the most complete paleoseismic record for the Wellington Fault. This approach also seems to largely overcome problems related to the size of subfaults. 0000015998 00000 n The scenario used for Wellington region emergency management planning is a major earthquake of the Wellington Fault of magnitude 7.6 on the Richter scale, resulting in 4-5 metre horizontal and 1m vertical fault displacement and widespread disruption to the roading network. / How do we know which fault is most likely to rupture next in Wellington? The 2011 Christchurch earthquake, for example, was the result of a 16km fault rupture. water, electricity, roads, telecommunications) crossing this fault. This is a difficult problem because, while we have a reasonable understanding of the low frequency behaviour (say 2-100 seconds period) of fault ruptures, we are not able to accurately model the high frequency behaviour (about ~1 Hz). endstream endobj 37 0 obj<> endobj 39 0 obj<> endobj 40 0 obj<>/Font<>/XObject<>/ProcSet[/PDF/Text/ImageB]/ExtGState<>>> endobj 41 0 obj<> endobj 42 0 obj<> endobj 43 0 obj<> endobj 44 0 obj<> endobj 45 0 obj[/ICCBased 60 0 R] endobj 46 0 obj<> endobj 47 0 obj<> endobj 48 0 obj<> endobj 49 0 obj<> endobj 50 0 obj<>stream startxref We have modelled a smooth rupture across this fault and generated synthetic seismograms for … This is how we deduce that the Wellington Fault has the highest probability of rupturing next in the Wellington region. 0000062013 00000 n Based on what we know about the Wellington fault, Online material: Movies of Wellington Fault rupture scenarios. Discon-tinuities along the fault trace within this proposed segment include an 18° northeastward swing in strike near Thorndon, The Wellington Fault last ruptured between 300 and 500 years ago with a magnitude 7.6 earthquake. This fault produces a large earthquake about every 500 to 1000 years. This is how we deduce that the Wellington Fault has the highest probability of rupturing next in the Wellington region. The trick in doing this is to correctly add up the contribution of each of the 1,500 subfaults with the correct timing and faulting behaviour. Click for big version Shepherds Gully Fault (yellow), Ohariu Fault (green), Wellington Fault (red) Click for big version The major fault running through Wellington City is about 50 per cent less likely to rupture in the next 100 years than previously thought, according to research carried out under the ‘It’s Our Fault’ project. In 1855 the Mw ~8.2 Wairarapa Earthquake resulted in uplift of the lower Hutt Valley area and created an expectation that future earthquakes would do the same. The fault rupture will lead to loss of a span, and while there are catch frames to prevent the span falling on the railyards, access will still be disrupted. H�����pr۬'�� led��,�Z�dX����T�{F��B�������͹�}�j��0\�FAy5zxo]�~u�MP1��\T�����MR�M���f��u�5j4`�}R���'���6��h+�23�Y�_�\�Z��ݳ�Y?�aX? Found inside – Page 34535.4 Wave-cut shore platforms on Wellington's south coast exposed by the 1855 ... Earthquakes associated with rupture on this fault have a characteristic ... Wellington Fault near Totara Park, Upper Hutt (1st of 2) The most recent rupture on the Wellington Fault has formed a low, straight scarp across California Park, Upper Hutt. We find that the crustal fault sources (Wellington Fault and Wairarapa Fault) pose less of an inundation hazard than the studied events on the Hikurangi subduction interface. Found inside – Page 240... of Wellington (Figure 7.1), much of its urban area lies in a zone which is expected to experience intensity MM10 when the Wellington fault ruptures, ... A full length rupture on this fault, which has an estimated magnitude of 7.6 (Dawe et al. With our present understanding of the Wellington and Wairarapa faults, it can be concluded that the 1855 Wairarapa earthquake retarded earth- Authors: R Benites, R Robinson, T Webb, P McGinty, Institute of Geological & Nuclear Sciences. 0000004109 00000 n This method, however, also seems to have some shortcomings. The Wellington Fault last ruptured between 170 and 370 years ago, and there is a 10 per cent chance it will rupture again within the next century, according to GNS Science. 1) including, especially, sites where recent investigations have yielded new insights into the fault’s rupture history and behaviour. Eastern seaboard widening of SH1 motorway also exposes new lanes to earthquake, coastal and sea level risks. The Wellington Fault poses the greatest threat out of all known fault to the Wellington region ... (Becker & Beban 2013). Land on the entire north-western side of the Wairarapa Fault was forced suddenly upwards, tilting Wellington Harbour and uplifting the seabed of the Cook Strait. Purely horizontal dextral faulting has been assumed. It is a segmented structure, of which the various segments probably rupture independently, though a rupture of any one may influence the timing of rupture … An international team that drilled almost a kilometre deep into New Zealand’s Alpine Fault, which is expected to rupture in a … The Wellington-Hutt-Valley segment of the Wellington Fault (Figure 1) is widely perceived to pose the greatest risk of any known active earthquake fault in New Zealand. 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Fault ’ s rupture history and behaviour no houses were built directly across it computation times the.

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