A three dimensional approximately half scale experimental subassemblage is currently being tested at the University of Canterbury to investigate the effect of precast-prestressed floor units, which do not span past the internal columns, on the seismic performance of reinforced concrete moment resisting frames. This paper reports the preliminary results from the test, with the focus on elongation within the plastic hinges and strength enhancement in the frames. The preliminary results have shown that elongation between the external and internal plastic hinges varies by more than two fold. With the addition of the prestressed floor units, the strength of the moment resisting frame used in the test was found to be 25% higher than the current code specified value. In other situations, particularly where there are more than 2 bays in a moment resisting frame, greater strength enhancement may be expected. Any underestimation of beam strength is undesirable as it may result in the development of nonductile failure modes in a major earthquake.
This participant-observation study explores the process of gathering and evaluating both financial and non-financial information and communication and transfer of that information within a medium-sized electrical service company in Christchurch, New Zealand. The previous literature has established the importance and the main characteristics of small and medium enterprises, mainly studying manufacturing companies. However, there has been little research done in New Zealand on the overall communication process and the financial and non-financial information usage in a small-medium enterprise. The Electrical Company has a flat structure which allows flexibility. The two owners understand the importance of financial management and use financial information extensively to ensure the business expenses are under control. The owners also gather and use non-financial information through talking to their accountant, their customers and people in the same industry and they keenly follow the news on the rebuilding of Christchurch after the recent earthquakes.
This paper provides a summary of the ground motions observed in the recent Canterbury, New Zealand earthquake sequence. The sequence occurred in a region of relatively moderate seismicity, 130km to the east of the Alpine Fault, the major plate-boundary in the region. From an engineering perspective, the sequence has been primarily comprised of the initial 04/09/2010 Darfield earthquake (Mw7.1) followed by the 22/02/2011 Christchurch earthquake (Mw6.3), and two aftershocks on 13/06/ 2011 (Mw5.3 and 6.0, respectively). The dense spacing of strong motions in the region, and their close proximity to the respective causative faults, has resulted in strong ground motions far exceeding the previous catalogue of strong motion observed in New Zealand. The observed ground motions have exhibited clear evidence of: (i) near-source directivity; (ii) sedimentary basin focusing, amplification and basin effect refraction; (iii) non-linear site response; (iv) cyclic mobility postliquefaction; and (v) extreme vertical ground motions exceeding 2g, among others.
This paper concerns the explicit consideration of near-fault directivity in conventional ground motion prediction models, and its implication for probabilistic seismic hazard analysis (PSHA) in New Zealand. The proposed approach utilises recently developed models by Shahi & Baker (2011), which account for both the 'narrowband' nature of the directivity pulse on spectral ordinates, and the probability of pulse occurrence at the site of interest. Furthermore, in order to correctly consider directivity, distributed seismicity sources are considered as finite-faults, as opposed to their (incorrect) conventional treatment as point-sources. The significance of directivity on hazard analysis results is illustrated for various vibration periods at generic sites located in Christchurch and Otira, two locations whose seismic hazard is comprised of notably different seismic sources. When compared to the PSHA results considering directivity and distributed seismicity as finite faults, it is shown that the NZS1170.5:2004 directivity factor is notably unconservative for all vibration periods in Otira (i.e. high seismic hazard region); and unconservative for Christchurch at short-to-moderate vibration periods ( < 3s); but conservative at long periods ( > 4s).
The performance of conventionally designed reinforced concrete (RC) structures during the 2011 Christchurch earthquake has demonstrated that there is greater uncertainty in the seismic performance of RC components than previously understood. RC frame and wall structures in the Christchurch central business district were observed to form undesirable cracks patterns in the plastic hinge region while yield penetration either side of cracks, and into development zones, were less than theoretical predictions. The implications of this unexpected behaviour: (i) significantly less available ductility; (ii) less hysteretic energy dissipation; and (iii) the localization of peak reinforcement strains, results in considerable doubt for the residual capacity of RC structures. The significance of these consequences has prompted a review of potential sources of uncertainty in seismic experimentation with the intention to improve the current confidence level for newly designed conventional RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, to consider the influence of loading history, concrete tensile strength, and reinforcement ratio on the performance of ‘real’ RC structures compared to experimental test specimens.
This paper presents the preliminary findings of a study on the resilience and recovery of organisations following the Darfield earthquake in New Zealand on 4 September 2010. Sampling included organisations proximal and distal to the fault trace, organisations located within central business districts, and organisations from seven diverse industry sectors. The research captured information on the challenges to, the impacts on, and the reflections of the organisations in the first months of recovery. Organisations in central business districts and in the hospitality sector were most likely to close while organisations that had perishable stock and livestock were more heavily reliant on critical services. Staff well-being, cash flow, and customer loss were major concerns for organisations across all sectors. For all organisations, the most helpful factors in mitigating the effects of the earthquake to be their relationship with staff, the design and type of buildings, and critical service continuity or swift reinstatement of services.
The Canterbury earthquakes are unique in that the there have been a series of major earthquakes, each with their own subsequent aftershock pattern. These have extended from the first large earthquake in September 2010 to currently, at the time of writing, two years later. The last significant earthquake of over magnitude 5.0 on the Richter scale was in May on 2012, and the total number of aftershocks has exceeded 12,000. The consequences, in addition to the loss of life, significant injury and widespread damage, have been far reaching and long term, with detrimental effects and still uncertain effects for many. This provides unique challenges for individuals, communities, organisations and institutions within Canterbury. This document reviews research-based understandings of the concept of resilience. A conceptual model is developed which identifies a number of the factors that influence individual and household resilience. Guided by the model, a series of recommendations are developed for practices that will support individual and household resilience in Canterbury in the aftermath of the 2010-2011 earthquakes.
This article explores the scope of small-scale radio to create an auditory geography of place. It focuses on the short-term art radio project The Stadium Broadcast, which was staged in November 2014 in an earthquake-damaged sports stadium in Christchurch, New Zealand. Thousands of buildings and homes in Christchurch have been demolished since the February 22, 2011, earthquake, and by the time of the broadcast the stadium at Lancaster Park had been unused for three years and nine months, and its future was uncertain. The Stadium Broadcast constructed a radio memorial to the Park’s 130-year history through archival recordings, the memories of local people, observation of its current state, and a performed site-specificity. The Stadium Broadcast reflected on the spatiality of radio sounds and transmissions, memory, postdisaster transitionality, and the impermanence of place.
Shaking table testing of a full-scale three storey resilient and reparable complete composite steel framed building system is being conducted. The building incorporates a number of interchangeable seismic resisting systems of New Zealand and Chinese origin. The building has a steel frame and cold formed steel-concrete composite deck. Energy is dissipated by means of friction connections. These connections are arranged in a number of structural configurations. Typical building nonskeletal elements (NSEs) are also included. Testing is performed on the Jiading Campus shaking table at Tongji University, Shanghai, China. This RObust BUilding SysTem (ROBUST) project is a collaborative China-New Zealand project sponsored by the International Joint Research Laboratory of Earthquake Engineering (ILEE), Tongji University, and a number of agencies and universities within New Zealand including BRANZ, Comflor, Earthquake Commission, HERA, QuakeCoRE, QuakeCentre, University of Auckland, and the University of Canterbury. This paper provides a general overview of the project describing a number of issues encountered in the planning of this programme including issues related to international collaboration, the test plan, and technical issues.
There is an increasing recognition that the seismic performance of buildings will be affected by the behaviour of both structural and non-structural elements. In light of this, work has been progressing at the University of Canterbury to develop guidelines for the seismic assessment of commercial glazing systems. This paper reviews the seismic assessment guidelines prescribed in Section C10 of the MBIE building assessment guidelines. Subsequently, the C10 approach is used to assess the drift capacity of a number of glazing units recently tested at the University of Canterbury. Comparing the predicted and observed drift capacities, it would appear that the C10 guidelines may lead to nonconservative estimates of drift capacity. Furthermore, the experimental results indicate that watertightness may be lost at very low drift demands, suggesting that guidance for the assessment of serviceability performance would also be beneficial. As such, it is proposed that improved guidance be provided to assist engineers in considering the possible impact that glazing could have on the structural response of a building in a large earthquake.
In 2016, the Building (Earthquake-prone Buildings) Amendment Act 2016 was introduced to address the issue of seismic vulnerability amongst existing buildings in Aotearoa New Zealand. This Act introduced a mandatory scheme to remediate buildings deemed particularly vulnerable to seismic hazard, as recommended by the 2012 Royal Commission into the Canterbury earthquake sequence of 2010–2011. This Earthquake-prone Building (EPB) framework is unusual internationally for the mandatory obligations that it introduces. This article explores and critiques the operation of the scheme in practice through an examination of its implementation provisions and the experiences of more recent seismic events (confirmed by engineering research). This analysis leads to the conclusion that the operation of the current scheme and particularly the application of the concept of EPB vulnerability excludes large numbers of (primarily urban) buildings which pose a significant risk in the event of a significant (but expected) seismic event. As a result, the EPB scheme fails to achieve its goals and instead may create a false impression that it does so
The Canterbury earthquakes and the rebuild are generation-defining events for twenty-first century Aotearoa/ New Zealand. This article uses an actor network approach to explore 32 women’s narratives of being shaken into dangerous disaster situations and reconstituting themselves to cope in socially innovative ways. The women’s stories articulate on-going collective narratives of experiencing disaster and coping with loss in ‘resilient’ ways. In these women’s experiences, coping in disasters is not achieved by talking through the emotional trauma. Instead, coping comes from seeking solace through engagement with one’s own and others’ personal risk and resourcefulness in ways that feed into the emergence of socially innovative voluntary organisations. These stories offer conceptual insight into the multivalent interconnections between resilience and vulnerabilities and the contested nature of post-disaster recovery in Aotearoa/New Zealand. These women gave voice to living through disasters resiliently in ways that forged new networks of support across collective and personal narratives and broader social goals and aspirations for Aotearoa/New Zealand’s future.
Research following the 2010-2011 Canterbury earthquakes investigated the minimum vertical reinforcement required in RC walls to generate well distributed cracking in the plastic hinge region. However, the influence of the loading sequence and rate has not been fully addressed. The new minimum vertical reinforcement limits in NZS 3101:2006 (Amendment 3) include consideration of the material strengths under dynamic load rates, but these provisions have not been validated at a member or system level. A series of tests were conducted on RC prisms to investigate the effect of loading rate and sequence on the local behaviour of RC members. Fifteen axially loaded RC prisms with the designs representing the end region of RC walls were tested under various loading rates to cover the range of pseudo-static and earthquake loading scenarios. These tests will provide substantial data for understanding the local behaviour of RC members, including hysteretic load-deformation behaviour, crack patterns, failure mode, steel strain, strain rate and ductility. Recommendations will be made regarding the effect of loading rate and reinforcement content on the cracking behaviour and ductility of RC members.
Very little research exists on total house seismic performance. This testing programme provides stiffness and response data for five houses of varying ages including contributions of non-structural elements. These light timber framed houses in Christchurch, New Zealand had minor earthquake damage from the 2011 earthquakes and were lateral load tested on site to determine their strength and stiffness, and preliminary damage thresholds. Dynamic characteristics were also investigated. Various loading schemes were utilised including quasi-static loading above the foundation, unidirectional loading through the floor diaphragm, cyclic quasi-static loading and snapback tests. Dynamic analysis on two houses provided the seismic safety levels of post-quake houses with respect to local hazard levels. Compared with New Zealand Building Standards all the tested houses had an excess of strength, damage is a significant consideration in earthquake resilience and was observed in all of the houses. A full size house laboratory test is proposed.
During the 2010 - 2011 Canterbury earthquake sequence, extensive liquefaction was observed in many areas of Christchurch city and its surroundings, causing widespread damage to buildings and infrastructure. While existing simplified methods were found to work well in some areas of the city, there were also large areas where these methods did not perform satisfactorily. In some of these cases, researchers have proposed that layers of fine grained material within the soil profile may be responsible for preventing the manifestation of liquefaction. This paper presents preliminary findings on the mechanisms at play when pressure differentials exist across a clay layer. It is found that if the clay layer is unable to distort, then pore fluid is unable to break-through the layer even with relatively high pressures, resulting in dissipation of excess pore pressures by seepage. If the layers are however able to distort, then it is possible for the pore fluid to break through the clay layer, potentially resulting in adverse effects in terms of the severity of liquefaction.
Earthquake-triggered soil liquefaction caused extensive damage and heavy economic losses in Christchurch during the 2010-2011 Canterbury earthquakes. The most severe manifestations of liquefaction were associated with the presence of natural deposits of clean sands and silty sands of fluvial origin. However, liquefaction resistance of fines-containing sands is commonly inferred from empirical relationships based on clean sands (i.e. sands with less than 5% fines). Hence, existing evaluation methods have poor accuracy when applied to silty sands. The liquefaction behaviour of Christchurch fines-containing (silty) sands is investigated through a series of Direct Simple Shear (DSS) tests. This type of test better resembles earthquake loading conditions in soil deposits compared to cyclic triaxial tests. Soil specimens are reconstituted in the laboratory with the water sedimentation technique. This preparation method yields soil fabrics similar to those encountered in fluvial soil deposits, which are common in the Christchurch area. Test results provide preliminary indications on how void ratio, relative density, preparation method and fines content influence the cyclic liquefaction behaviour of sand-silt mixtures depending on the properties of host sand and silt.
Well-validated liquefaction constitutive models are increasingly important as non-linear time history analyses become relatively more common in industry for key projects. Previous validation efforts of PM4Sand, a plasticity model specifically for liquefaction, have generally focused on centrifuge tests; however, pore pressure transducers installed at several free-field sites during the Canterbury Earthquake Sequence (CES) in Christchurch, New Zealand provide a relatively unique dataset to validate against. This study presents effective stress site response analyses performed in the finite difference software FLAC to examine the capability of PM4Sand to capture the generation of excess pore pressures during earthquakes. The characterization of the subsurface is primarily based on extensive cone penetration tests (CPT) carried out in Christchurch. Correlations based on penetration resistances are used to estimate soil parameters, such as relative density and shear wave velocity, which affect liquefaction behaviour. The resulting free-field FLAC model is used to estimate time histories of excess pore pressure, which are compared with records during several earthquakes in the CES to assess the suitability of PM4Sand.
This paper explores the scope of small-scale radio to create an auditory geography of place. It focuses on the short term art radio project The Stadium Broadcast, which was staged in November 2014 in an earthquake-damaged sports stadium in Christchurch, New Zealand. Thousands of buildings and homes in Christchurch have been demolished since the Februrary 22, 2011 earthquake, and while Lancaster Park sports stadium is still standing, it has been unused since that date and its future remains uncertain. The Stadium Broadcast constructed a radio memorial to the Park’s 130 year history through archival recordings, the memories of local people, observation of its current state, and a performed site-specificity. The Stadium Broadcast reflected on the spatiality of radio sounds and transmissions, memory, post-disaster transitionality, and the im-permanence of place.
This presentation summarizes the development of high-resolution surficial soil velocity models in the Canterbury, New Zealand basin. Shallow (<30m) shear wave velocities were primarily computed based on a combination of a large database of over 15,000 cone penetration test (CPT) logs in and around Christchurch, and a recently-developed Christchurch-specific empirical correlation between soil shear wave velocity and CPT. Large active-source testing at 22 locations and ambient-wavefield surface wave and H/V testing at over 80 locations were utilized in combination with 1700 water well logs to constrain the inter-bedded stratigraphy and velocity of Quaternary sediments up to depths of several hundred meters. Finally, seismic reflection profiles and the ambient-wavefield surface wave data provide constraint on velocities from several hundred meters to several kilometres. At all depths, the high resolution data illustrates the complexity of the soil conditions in the region, and the developed 3D models are presently being used in broadband ground motion simulations to further interpret the observed strong ground motions in the 2010-2011 Canterbury earthquake sequence.
This article argues that active coordination of research engagement after disasters has the potential to maximize research opportunities, improve research quality, increase end-user engagement, and manage escalating research activity to mitigate ethical risks posed to impacted populations. The focus is on the coordination of research activity after the 22nd February 2011 Mw6.2 Christchurch earthquake by the then newly-formed national research consortium, the Natural Hazards Research Platform, which included a social science research moratorium during the declared state of national emergency. Decisions defining this organisation’s functional and structural parameters are analyzed to identify lessons concerning the need for systematic approaches to the management of post disaster research, in collaboration with the response effort. Other lessons include the importance of involving an existing, broadly-based research consortium, ensuring that this consortium's coordination role is fully integrated into emergency management structures, and ensuring that all aspects of decision-making processes are transparent and easily accessed.
Elevated levels of trace elements in the environment are of great concern because of their persistence, and their high potential to harm living organisms. The exposure of aquatic biota to trace elements can lead to bioaccumulation, and toxicity can result. Furthermore, the transfer of these elements through food chains can result in exposure to human consumers. Sea-fill or coastal fill sites are among the major anthropogenic sources of trace elements to the surrounding marine environment. For example, in the Maldives, Thilafushi Island is a sea-fill site consisting of assorted municipal solid waste, with multiple potential sources of trace elements. However, there is limited data on environmental trace element levels in the Maldives, and although seafood is harvested from close to this site, there is no existing data regarding trace element levels in Maldivian diets. Following the Christchurch earthquakes of 2011,
The earthquake sequence has resulted in significant physical and reputational damage to the Canterbury tourism industry. Eighteen months after the earthquakes inbound tourism data is still below pre-earthquake levels, with Canterbury operators reporting that the industry has not bounced back to where it was before September 2010. Outcomes of the earthquakes on business performance highlight there were winners and losers in the aftermath. Recovery of inbound tourism markets is closely tied to the timeframe to rebuild the CBD of Christchurch. Reinstating critical tourism infrastructure will drive future tourism investment, and allow tourism businesses to regenerate and thrive into the future. A blueprint for rebuilding the CBD of Christchurch was released by the Christchurch City Council in July 2012, and has been well received by tourism stakeholders in the region. The challenge now is for city officials to fund the development projects outlined in the blueprint, and to rebuild the CBD as quickly as possible in order to help regenerate the tourism industry in Christchurch, Canterbury and the rest of the South Island
Deep shear wave velocity (Vs) profiles (>400 m) were developed at 14 sites throughout Christchurch, New Zealand using surface wave methods. This paper focuses on the inversion of surface wave data collected at one of these sites, Hagley Park. This site is located on the deep soils of the Canterbury Plains, which consist of alluvial gravels inter-bedded with estuarine and marine sands, silts, clays and peats. Consequently, significant velocity contrasts exist at the interface between geologic formations. In order to develop realistic velocity models in this complex geologic environment, a-priori geotechnical and geologic data were used to identify the boundaries between geologic formations. This information aided in developing the layering for the inversion parameters. Moreover, empirical reference Vs profiles based on material type and confining pressure were used to develop realistic Vs ranges for each layer. Both the a-priori layering information and the reference Vs curves proved to be instrumental in generating realistic velocity models that account for the complex inter-bedded geology in the Canterbury Plains.
The Canterbury Earthquake Sequence (CES) was a monumental natural disaster in Aotearoa New Zealand that permanently altered Ōtautahi Christchurch’s geography. Following the earthquake events, the central city was in need of recovery and regeneration to return to being an enhanced and thriving space. The Christchurch Central Recovery Plan (CCRP) was developed to outline the aspirations, visions and challenges associated with rebuilding the central city. The purpose of this research was to review the current status of the CCRP, with a particular focus on identifying the projects that have or have not progressed. This research sought to understand which aspects of a post-disaster recovery plan have contributed to successful post-disaster recovery in Ōtautahi Christchurch. Secondary data was used to identify successes and failures in this regard. The results highlighted the top-down approach taken by the central government in the recovery process and a notable lack of community engagement throughout the CCRP. However, there were some projects and aspirations that have enabled Ōtautahi Christchurch to become a thriving city and express its regenerated identity at a local, national, and international level.
An as-built reinforced concrete (RC) frame building designed and constructed according to pre-1970s code design construction practice has been recently tested on the shake table at the University of Canterbury. The specimen, 1/2.5 scaled version of the original prototype, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. Following the benchmark test, a retrofit intervention has been proposed to rehabilitate the tested specimen. In this paper, detailed information on the assessment and design of the seismic retrofit procedure using GFRP (glass fibre reinforced polymer) materials is given for the whole frame. Hierarchy of strength and sequence of events (damage mechanisms) in the panel zone region are evaluated using a moment-axial load (M-N) interaction performance domain, according to a performance-based retrofit philosophy. Specific limit states or design objectives are targeted with attention given to both strength and deformation limits. In addition, an innovative retrofit solution using FRP anchor dowels for the corner beam-column joints with slabs is proposed. Finally, in order to provide a practical tool for engineering practice, the retrofit procedure is provided in a step-by step flowchart fashion.
This paper outlines the deconstruction, redesign and reconstruction of a 2 storey timber building at the University of Canterbury, in Christchurch, New Zealand. The building consists of post tensioned timber frames and walls for lateral and gravity resistance, and timber concrete composite flooring. Originally a test specimen, the structure was subjected to extreme lateral displacements in the University structural testing laboratory. This large scale test of the structural form showed that post tensioned timber can withstand high levels of drift with little to no structural damage in addition to displaying full recentering characteristics with no residual displacements, a significant contributor to post earthquake cost. The building subsequently has been dismantled and reconstructed as offices for the Structural Timber Innovation Company (STIC). In doing this over 90% of the materials have been recycled which further enhances the sustainability of this construction system. The paper outlines the necessary steps to convert the structure from a test specimen into a functioning office building with minimal wastage and sufficient seismic resistance. The feasibility of recycling the structural system is examined using the key indicators of cost and time.
Disaster recovery is significantly affected by funding availability. The timeliness and quality of recovery activities are not only impacted by the extent of the funding but also the mechanisms with which funding is prioritised, allocated and delivered. This research addresses the impact of funding mechanisms on the effectiveness and efficiency of post-disaster demolition and debris management programmes. A qualitative assessment of the impacts on recovery of different funding sources and mechanisms was carried out, using the 2010 Canterbury Earthquake as well as other recent international events as case studies. The impacts assessed include: timeliness, completeness, environmental, economic and social impacts. Of the case studies investigated, the Canterbury Earthquake was the only disaster response to rely solely on a privatised approach to insurance for debris management. Due to the low level of resident displacement and low level of hazard in the waste, this was a satisfactory approach, though not ideal. This approach has led to greater organisational complexity and delays. For many other events, the potential community wide impacts caused by the prolonged presence of disaster debris means that publicly funded and centrally facilitated programmes appear to be the most common and effective method of managing disaster waste.
This research examines a surprising partner in emergency management - a local community time bank. Specifically, we explain the role of the Lyttelton Time Bank in promoting community resiliency following the Canterbury earthquakes in 2010 and 2011. A time bank is a grassroots exchange system in which members trade services non-reciprocally. This exchange model assumes that everyone has tradable skills and all labour is equal in value. One hour of any labour earns a member one time bank hour, which can be used to purchase another member’s services. Before the earthquakes struck, the Lyttelton Time Bank (TB) had organised over 10% of the town’s residents and 18 local organisations. It was documenting, developing, and mobilising skills to solve individual and collective problems. This report examines the Lyttelton Time Bank and its’ role before, during, and after the earthquakes based on the analysis of over three and a half years of fieldwork, observations, interviews, focus groups, trading activity, and secondary data.
The Civil Defense understanding of the role of radio in disaster tends to focus on its value in providing essential information during and after the event. However this role is compromised when a station’s premises are destroyed, or rendered inaccessible by official cordons. The Radio Quake study examines how radio stations in Christchurch managed to resume broadcasting in the aftermath of the earthquake of February 22, 2011. In New Zealand’s heavily networked and commercialised radio environment there is a significant disparity between networked and independent stations’ broadcast commitments and resourcing. All Christchurch radio broadcasters were forced to improvise new locations, complex technical workarounds, and responsive styles of broadcasting after the February 22 earthquake, but the need to restore, or maintain, a full on air presence after the earthquake, rested entirely on often financially tenuous, locally owned and staffed independent radio: student, Iwi, community access, and local commercial stations. This paper will explore the resourcefulness and resilience of broadcasters riding out the aftershocks in hotels, motels, bedrooms, and a horse truck, using digital technologies in new ways to reimagine the practice of radio in Christchurch.
Using case studies from the 2010-2011 Canterbury, New Zealand earthquake sequence, this study assesses the accuracies of paleoliquefaction back-analysis methods and explores the challenges, techniques, and uncertainties associated with their application. While liquefaction-based back-analyses have been widely used to estimate the magnitudes of paleoearthquakes, their uncertain efficacies continue to significantly affect the computed seismic hazard in regions where they are relied upon. Accordingly, their performance is evaluated herein using liquefaction data from modern earthquakes with known magnitudes. It is shown that when the earthquake source location and mechanism are known, back-analysis methods are capable of accurately deriving seismic parameters from liquefaction evidence. However, because the source location and mechanism are often unknown in paleoseismic studies, and because accurate interpretation is shown to be more difficult in such cases, new analysis techniques are proposed herein. An objective parameter is proposed to geospatially assess the likelihood of any provisional source location, enabling an analyst to more accurately estimate the magnitude of a liquefaction-inducing paleoearthquake. This study demonstrates the application of back-analysis methods, provides insight into their potential accuracies, and provides a framework for performing paleoliquefaction analyses worldwide.
