bluuebunny/crossref_metadata_2025 huggingface dataset:
Marmara Sea earthquake reconnaissance report
Authors: Sharpe R.D. , Bradshaw D. , Brown N. , Van Dissen R. , Kirkcaldie D. , McManus K. J. , Pham T. , Stevenson C.
Published: January 2020

On 17 August 1999 a Mw 7.4 earthquake struck western Turkey killing at least 15,000 people and leaving some 600,000 homeless. Three weeks later a New Zealand Society for Earthquake Engineering reconnaissance team was sent to the area to investigate the causes of the destruction and the reported confusion and delay in the emergency response and to bring back information that will help to better prepare for similar earthquakes in New Zealand. Few new lessons were to be learned in structural behaviour, the numerous collapsed apartment buildings were not adequately designed or constructed for the intensity of shaking they were subjected to. The enormous scale of the disaster and extent of damage far exceeded media reports and simply overwhelmed the emergency response preparations that were in place. New Zealand is ill prepared for a disaster of such magnitude.
Passive control of structures for seismic loads
Authors: Buckle Ian G.
Published: January 2020

The control of structures to improve their performance during earthquakes was first proposed more than a century ago. But it has only been in the last 25 years that structures have been successfully designed and built using earthquake protective systems. Today these systems range from simple passive devices to fully active systems. This paper focuses on passive control and reviews recent developments in the state-of-the-art.

Passive systems include tuned mass dampers, seismic (base) isolation systems, mechanical energy dissipators, and the like. Major developments in the theory, hardware, design, specification, and installation of these systems have permitted significant applications to buildings, bridges, and industrial plant. Applications are now found in almost all of the seismically active countries of the world, but principally in Italy, Japan, New Zealand and the United States. Noteworthy advantages have been demonstrated when retrofitting existing structures, and designing high-performance structures such as hospitals, emergency response facilities, defense installations, and critical bridges. Field experience in recent earthquakes has confirmed these expectations.

There are however limitations to the use of passive systems and these deserve further study and research. They include the uncertainty of response in the near field of an active fault, the non- optimal behavior of passive systems for both small and large earthquakes, and a lack of certainty about the ultimate limit states in unexpectedly large events. As a consequence, in some jurisdictions, code provisions for passive systems are more onerous than for conventional construction, which is a strong disincentive to their use. The limited availability of design guidance in text books, code commentaries, and other design aids are further impediments to the wider use of these systems.
Risk assessment and retrofit of existing buildings
Authors: Holmes William T.
Published: January 2020

The structural risk assessment and evaluation process is broken into the steps of Develop knowledge of as-built conditions, Determine local response characteristics, Create mathematical model, Perform global analysis, Determine acceptability, and Select retrofit procedure/Classify per evaluation procedure and each step discussed. These steps, in general, are major topics of their own and only a few of the primary engineering issues that affect the state of the art in this area are included in this paper. The development of conceptual retrofit schemes is also discussed. Many aspects of earthquake engineering are directly related to risk assessment and retrofit, including performance based engineering, characterization of seismic hazard, performance of nonstructural systems, costs of retrofit, and public policy. These subjects and their relationship to risk assessment and retrofit are briefly described.
Engineering management of lifeline systems under earthquake risk
Authors: Kameda Hiroyuki
Published: January 2020

The state-of-the-art of lifeline system management under earthquake risk is discussed. After a historical overview and specific features of lifeline earthquake engineering, elements of lifeline earthquake engineering practice are presented. They include outline of lifeline protection technologies, lessons from recent urban earthquakes particularly Kobe 1995, and seismic code developments. Then two topics are addressed specifically. First seismic reliability under system interaction is discussed with its general scheme and an analytical methodology. Next, criteria for lifeline performance is discussed with an emphasis on quantification of qualitative issues that are needed particularly in implementation processes. After presenting a general framework, two cases, one from Kobe on water customers' response, and one from California regarding funding procedure for seismic improvement. Finally, future orientations of earthquake engineering and its relation to lifeline earthquake engineering is addressed. It is emphasized that we should establish a third generation earthquake engineering where structural and geotechnical mitigation, crisis management, and sustainable development should be integrated through multi-disciplinary developments. Some examples of multi-disciplinary research initiatives are introduced.
Seismic design and retrofit of bridges
Authors: Kawashima Kazuhiko
Published: January 2020

The 1989 Loma Prieta, 1994 Northridge and 1995 Hyogo-ken nanbu earthquakes caused major damage to bridges and these events together with the research triggered as a consequence of the earthquakes has led to significant advances in bridge seismic design and retrofitting. This paper presents how this has affected design philosophies and design codes in EC, New Zealand, Japan and USA in recent years, with emphasis on the Japanese experience in the aftermath of the 1995 H-k-n earthquake. Near field ground motion, linear/nonlinear static/dynamic response analyses, treatment of liquefaction-induced lateral ground movement are described. Comparison of design philosophy, design force and ductility requirements are compared among the EC-8, New Zealand, Japanese, AASHTO and Caltrans/ATC-32 codes. Seismic retrofitting which was conducted in Japan after the Hyogo-ken nanbu earthquake over 29,000 reinforced concrete columns is described.
Design for low/moderate seismic risk
Authors: Pinto Paolo E.
Published: January 2020

The increase of knowledge about seismic hazard worldwide, associated to an increase of awareness of the potential losses due to earthquakes, and economic progress allowing for policies of risk reduction, have led several countries in which seismic hazard was formerly ignored to pay greater attention to seismic design. The paper deals with a number of aspects related to this increased interest. It is first discussed, with reference to the solutions adopted in a few countries, the problem of where to put the lower limit to seismic intensity for which explicit seismic design is worth being carried out. It is shown that the limit varies considerably among countries, depending on economic conditions and on the general quality of the constructions. Based on the results of analytical simulations illustrated in the paper, it is concluded that modern RC buildings can have a substantial capacity to resist earthquake motions, if they have a regular configuration and are correctly designed for gravity loads only. In terms of PGA, this capacity may go up to 0.15 - 0.25g for structural damages still far below the ultimate state. This stresses the greater importance, especially in regions of moderate seismicity, of providing the profession with documents of good practice, rather than with analytically sophisticated codes. Looking at the future, ample space is given in the paper to discuss about which one of the two design methods, the established force- based or the emerging displacement-based is best suited to the needs specific to L/M risk zones. In their present state, they are both less effective for L/M areas than in ones of high seismicity. The DBD approach offers better perspectives for being extended to the L/M case on more rational bases.
Performance based seismic design
Authors: Priestley M. J. N.
Published: January 2020

One of the major developments in seismic design over the past 10 years has been increased emphasis on limit states design, now generally termed Performance Based Engineering. Three techniques - the capacity spectrum approach, the N2 method and direct displacement-based design have now matured to the stage where seismic assessment of existing structures, or design of new structures can be carried out to ensure that particular deformation-based criteria are met.

The paper will outline and compare the three methods, and discuss them in the context of traditional force-based seismic design and earlier design approaches which contained some elements of performance based design. Factors defining different performance states will be discussed, including the need, not yet achieved, to include residual displacement as a key performance limit. Some emphasis will be placed on soil-related problems, and the incorporation of soil/structure interaction into performance-based design. It will be shown that this is relatively straightforward and results in consistent design solutions not readily available with force-based designs using force-reduction factors.
Seismic hazard evaluation
Authors: Somerville Paul
Published: January 2020

This paper reviews concepts and trends in seismic hazard characterization that have emerged in the past decade, and identifies trends and concepts that are anticipated during the coming decade. New methods have been developed for characterizing potential earthquake sources that use geological and geodetic data in conjunction with historical seismicity data. Scaling relationships among earthquake source parameters have been developed to provide a more detailed representation of the earthquake source for ground motion prediction. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude - distance - soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near- fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes. The probabilistic approach to characterizing the ground motion that a given site will experience in the future is very compatible with current trends in earthquake engineering and the development of building codes. Performance based design requires a more comprehensive representation of ground motions than has conventionally been used. Ground motions estimates are needed at multiple annual probability levels, and may need to be specified not only by response spectra but also by suites of strong motion time histories for input into time-domain non-linear analyses of structures.
Active, semi-active and hybrid control of structures
Authors: Soong T.T. , Spencer B.F.
Published: January 2020

In recent years, considerable attention has been paid to research and development of passive and active structural control devices, with particular emphasis on alleviation of wind and seismic response of buildings and bridges. In both areas, serious efforts have been undertaken to develop the structural control concept into a workable technology, and today we have many such devices installed in a wide variety of structures.

The focus of this state-of-the-art paper is on active, semi-active and hybrid structural control with seismic applications. These systems employ controllable force devices integrated with sensors, controllers and real-time information processing. This paper includes a brief historical outline of their development and an assessment of the state-of-the-art and state-of-the-practice of this exciting, and still evolving, technology. Also included in the discussion are their advantages and limitations in the context of seismic design and retrofit of civil engineering structures.
Understanding torsional phenomena in ductile systems
Authors: Paulay Tom
Published: January 2020

Recent studies provided opportunities to review some of the principles, which have been used in the formulations of internationally accepted code-recommendations relevant to the seismic design of ductile buildings also subjected to torsional phenomena. With the progress of this study, features emerged which are considered to have contributed to a better understanding of structural behaviour. Moreover, the identification of deeply embedded fallacies, relevant to ductile response, suggested the introduction of some changes in seismic design strategies, yet not widely known or appreciated. Reasons for necessary re-interpretations of traditional structural properties, together with illustrative examples, demonstrating applications, rather than set code-type rules, are offered.
Direct displacement-based seismic design of concrete buildings
Authors: Priestley M.J.N. , Kowalsky M.J.
Published: January 2020

A seismic design procedure is developed to enable concrete buildings to be designed to achieve a specified acceptable level of damage under the design earthquake. The acceptable limit is defined as a displacement profile related to limit material strains or code specified drift limits. In this procedure, the elastic properties, including initial stiffness, strength and period, are the end product of the design rather than the starting point. It is shown that the procedure is simple to apply, and results in significant differences from the more conventional force-based procedure. Designs for multi-storey frame and wall buildings are presented, and target displacements are compared with results from inelastic time-history analysis.
Comparative preparedness in New Zealand and the Philippines for response to, and recovery from, volcanic eruptions
Authors: Manville V. , Johnston D. , Stammers S. , Scott B.
Published: January 2020

New Zealand and the Philippines are two of the most tectonically and volcanically active regions in the world, due to their setting as large island chains on the convergent margin of the Pacific Plate. The Philippines has experienced numerous volcanic disasters over the past 400 years with the loss of over 7000 lives and considerable damage to infrastructure. The 1991 eruption of Mount Pinatubo, after 500 years of dormancy, was the largest volcanic eruption globally in the last 50 years, with serious socio-economic consequences for the Philippines. The 1995-6 eruptions of New Zealand's Mount Ruapehu, were the most serious volcanic activity experienced in the country over the last 50 years, but occurred at a frequently active volcano for which monitoring, hazard assessment, and response systems were already in place. Although the eruptions differ in size by two orders of magnitude, they illustrate how volcanic activity impacts infrastructure and society at different levels of economic development and vulnerability. Two of New Zealand's volcanic centres, Taupo and Okataina, have the potential to generate eruptions of a similar, or even greater, scale than Pinatubo. Therefore, lessons learnt from the Philippine experience will be of vital importance in planning for the mitigation of future volcanic disasters in New Zealand.
Quantifying the hazard of large subduction thrust earthquakes in Hawke's Bay
Authors: Reyners Martin
Published: January 2020

Beneath Hawke's Bay, the interface between the subducted Pacific and overlying Australian plates lies at shallow depth - within the depth range where large subduction thrust earthquakes are expected. Determining the likely size of such earthquakes is thus a major issue in quantifying the seismic hazard of the region. Here we use recent seismological, geodetic and geologic research results to estimate the rupture dimensions, magnitude and recurrence of a large subduction thrust event. The estimated rupture zone extends 45 km downdip, from 15 km to 22 km depth on the plate interface, and 120 km along strike, from 45 km southwest of Napier to 10 km northeast of Wairoa. This equates to an Mw 7.7 earthquake. The estimated recurrence of such an event depends on the coupling coefficient (i.e. the ratio of seismic slip to total slip) at the plate interface, which is not well determined. Our preferred range for this coefficient is 0.3-0.5, which yields a recurrence interval range of 250-400 years. Such recurrence is broadly consistent with the geological record of subsidence in the Ahuriri Lagoon near Napier in the 3500 years prior to the Ms 7.8 Hawke's Bay earthquake of 1931.
Improving the resistance of structures to earthquakes
Authors: Park R.
Published: January 2020

The past occurrence of earthquakes in New Zealand and the likelihood of a major earthquake in Christchurch are considered. The causes of damage by earthquakes are discussed and typical possible types of damage to building and bridge structures are described with reference to the 1995 Kobe earthquake. The design of building and bridge structures for earthquake resistance by the ductile design approach is covered, including performance criteria, structural configuration, design seismic forces, mechanisms of post-elastic deformation, capacity design, detailing of reinforcement for ductility and control of deflections. Design using base isolation and mechanical energy dissipating devices is also outlined. The extensive use of precast concrete in buildings in New Zealand is described. Finally the seismic assessment and upgrading of old structures and the earthquake resistance of lifelines of communities (transportation, utilities and communications) are briefly considered.
Seismic pounding of a case of adjacent multiple-storey buildings of differing total heights considering soil flexibility effects
Authors: Rahman A. M. , Carr A. J. , Moss P. J.
Published: January 2020

Collisions between adjacent structures due to insufficient separation gaps have been witnessed in almost every major earthquake since the 1960's. Although many analytical, numerical and experimental studies have been conducted into the pounding phenomenon, the number of those which take into account the effects of the underlying soil mass on the dynamic response of the colliding structures are almost negligible. The present study incorporates the effects of soil flexibility on the inelastic dynamic response of a particular case of adjacent 12- and 6-storey reinforced concrete moment-resisting frames. The time- history response of this system (linear soil behaviour and nonlinear structural response) subjected to actual earthquake records is evaluated by means of the structural analysis software RUAUMOKO developed at the University of Canterbury. A simple mass-spring-dashpot model is used to represent the frequency independent dynamic soil properties. Impacts at storey levels only are considered.

This study highlights serious inconsistencies in the assumptions of previous pounding studies, which neglect the effects of soil flexibility. Also, the pounding response of the adjacent structures is found to be highly sensitive to the characteristics and direction of the seismic excitation.
Preparation of the New Zealand earthquake catalogue for a probabilistic seismic hazard analysis
Authors: McGinty Peter
Published: January 2020

The seismic hazard from ground motions during a New Zealand earthquake is variable, and is dependent on the different tectonic processes that occur throughout the country. A modem probabilistic seismic hazard analysis (PSHA) combines various data sets to take account of these different environmental effects and rates of occurrence. Earthquake catalogue data can be used to give the rate of background or distributed seismicity in historical times, while paleoseismic data can be used to constrain the return time of large earthquakes. The background seismicity is assumed to occur as a time-independent Poisson process. To apply this assumption to a new PSHA of New Zealand, completeness levels for the New Zealand earthquake catalogue were established, and aftershocks or clusters of events that occurred close together in both space and time were removed from the catalogue. The level of hazard in a region can be depth-dependent, that is the risk of a large earthquake may come from a shallow crustal event or a deep subduction zone event, both having the same epicentral location but resulting in different levels of damage. The New Zealand earthquake catalogue has too many events that have been assigned restricted depths to be ignored. These events have been statistically redistributed into shallow crustal zones or deep subducted slab zones based on the last eleven years of catalogue data, when improvements in technology have reduced the number of restricted events.
Seismic behavior and retrofit of pre-1970's as-built exterior beam-column joints reinforced by plain round bars
Authors: Liu A. , Park R.
Published: January 2020

Four exterior beam-column joints reinforced by plain round bars designed according to pre-1970's codes were subjected to simulated seismic loading. Each of the test units was full size in scale. The main test variables were the manner in which the longitudinal beam bars were hooked in the joint core and the level of the axial load applied to the columns. The amount of transverse reinforcement in the beams, columns and joint cores was very small, as was typical of the pre-1970's. The tests on the units demonstrated that the available stiffness and strength was low when the axial load was zero. The final failure occurred due to opening of the beam bar hooks in tension and column bar buckling, irrespective of the hook details of the beam bars. The presence of axial compressive load of 0.25fc'Ag on the columns delayed the failure initiated by the beam bar hooks, leading to much improved stiffness and strength of the units. In one unit with beam bar hooks bent away from the joint core, the column regions adjacent to the joint core were jacketed with fibre-glass and the unit when tested showed much improved stiffness and strength. When compared with the results of similar units reinforced by deformed bars, the units reinforced by plain round bars showed less joint shear distortion but more opening of beam bar hooks in tension and column bar buckling. As a result, premature concrete tension cracking failure along the outer layer of column bars adjacent to the beam bar hooks was enhanced, and the attained stiffness and the force strength were significantly lower, especially the stiffness.
Influence of loading history on the response of a reinforced concrete beam
Authors: Ingham J.M. , Liddell D. , Davidson B.J.
Published: January 2020

An investigation considering the influence of loading histories on the performance of a reinforced concrete beam plastic hinge is described. Twelve loading histories were considered, including conventional procedures employed in the United States, Japan and New Zealand, and artificially generated histories derived from recorded earthquake ground motions. Details of the prototype structure and the test beam are described, followed by comprehensive reporting o f experimental data. Performance descriptors and further treatment of the experimental data are presented in a companion paper.
The 1942 Wairarapa, New Zealand, earthquakes
Authors: Downes G.L. , Dowrick D.J. , Van Dissen R.J. , Taber J.J. , Hancox G.T. , Smith E.G.C.
Published: January 2020

In 1942, two large earthquakes, on June 24 (Mw 7.2) and August 1 (UT) (Mw 6.8), strongly shook the lower North Island, causing widespread moderate to severe damage. A third earthquake (Ms 6.0) occurred in the same area on December 2.

These earthquakes have now been studied in detail by re-analysing seismograms from 1942 and by the collection and analysis of contemporary technical information and descriptive accounts from many sources. Results include new locations for the three main earthquakes and other moderate magnitude earthquakes in the sequence, summaries of building, lifelines and ground damage, new isoseismal maps and maps showing the distribution of landslides, liquefaction and other ground damage. The study has provided valuable information on the performance of buildings and lifelines in urban and small town environments at high intensities (MM8) and on the distribution of damaged buildings in central Wellington in relation to published ground shaking hazard microzoning maps and foreshore reclamation units.

An important result is that scarp-like features described after the June earthquake as surface fault rupture are probably landslide-related rather than tectonically produced. This result and the lack of evidence for any other surface fault rupture, the closeness in time and space of the earthquakes both within the sequence and with the 1934 Pahiatua earthquake, and the similarity of the sequence to the 1990 Weber earthquakes have important implications for seismic hazard assessment of this part of the Hikurangi Margin.
Earthquake building damage in developing countries
Authors: Charleson A.W. , Fyfe G.D.
Published: January 2020

This study reviews twenty-nine earthquake reconnaissance reports from developing countries in the period from 1990-1998. After identifying trends in the different types and causes of damage to buildings reviewed in the reports, the paper suggests areas where earthquake damage mitigation should be focussed; namely architectural and engineering conceptual design, engineering details and construction. An analysis of all causes of seismic damage suggests conceptual design is the most important area to focus on, and that codes or standards must include provisions to prevent poor building configurations. Finally, the paper considers the nature of reconnaissance teams and their reports. It comments on teams' objectives and concludes by suggesting how teams might contribute towards improving the mitigation of earthquake building damage in developing countries more directly.
Liquefaction at the Imperial Valley Wildlife Site
Authors: Davis R.O. , Berrill J.B.
Published: January 2020

In November 1987, two earthquakes occurred near a site in the Imperial Valley, California, where extensive field instrumentation had been placed by the US Geological Survey. The site was part of a wildlife refuge and has come to be called the Wildlife Site, or simply Wildlife. Some controversy arose subsequent to the earthquakes because of concern the field piezometers at the site may not have responded accurately in the second, larger earthquake. In this paper we re-examine the data from both earthquakes in an effort to (i) better understand the response of Wildlife during shaking, (ii) shed some light on the validity of the measured pore pressures from the larger earthquake, and (iii) investigate an alternative hypothesis for how liquefaction may develop.
Monotonic non-linear analysis of reinforced concrete knee joints using strut-and-tie computer models
Authors: To N.H.T. , Ingham J.M. , Sritharan S.
Published: January 2020

This paper presents the continuation of research considering the analysis of reinforced concrete bridge knee joints subjected to in-plane seismic loads. Strut-and-tie models incorporating rational joint force transfer mechanisms were developed to capture the non-linear inelastic response measured in four large-scale bridge knee joint tests. These models corresponded to different joint reinforcement detailing types and were analysed with Drain-2DX using non-linear truss elements. Obtained results were in satisfactory agreement with the measured displacement envelopes.
Damage ratios for domestic property in the magnitude 7.2 1968 Inangahua, New Zealand, earthquake
Authors: Dowrick D.J. , Rhoades D.A. , Davenport P.N.
Published: January 2020

An analysis of damage costs to domestic property in the Mw 7.2 Inangahua, New Zealand, earthquake of 23 May 1968 (U.T.) has allowed the evaluation of the vulnerability of domestic property for six intensity zones, from MM5 - MM10 inclusive. For no other earthquake worldwide has the vulnerability of any class of property been examined in so many intensity zones, and the effect of brittle chimneys on damage levels has been fully evaluated for the first time. The relative vulnerability of one and two storey houses has also been evaluated. The costs of damage were derived from about 8,000 insurance claims to the Earthquake and War Damage Commission. Damage ratios were evaluated for houses and their contents as functions of Modified Mercalli intensity. The indicators of vulnerability that were determined were the statistical distributions and mean values of damage ratios and the percentage of property items damaged for the six intensity zones. Comparisons have also been made with results from studies of other earthquakes.
Seismic ratings for degrading structural systems
Authors: Deam Bruce. L.
Published: January 2020

A new method has been proposed for rating the seismic resistance of degrading bracing elements used in buildings constructed to NZS 3604. Most of these bracing elements are formed from thin cladding panels nailed or screwed to light timber frames, but the rating method is also used for bracing elements constructed from other materials. A new analytical model was developed as part of this study to accurately model the load-displacement responses of these bracing elements. A continuous pseudo-dynamic test method was developed to assess the accuracy of the analytical model in the BRANZ structural laboratory. The analytical model accurately predicted the time-displacement responses of three, pseudo-dynamically tested, 5.4 m long, light timber framed wall specimens, providing confidence in its use.

The new rating method has shown that P21 rating procedure, used since 1979, was dangerously unconservative for the tested specimens. Factors that led to this discrepancy are briefly described. A simple modification to the current P21 rating procedure is proposed to re-rate specimens from existing test results, but this needs to be verified for a wider range of specimen responses than the three described herein.
From natural to cultural disaster
Authors: Jigyasu Rohit
Published: January 2020

This paper was originally presented in the UNESCO-ICOMOS Conference 'Earthquake-Safe: Lessons to be Learned from Traditional Construction. International Conference on the Seismic Performance of Traditional Buildings, Istanbul', Turkey, November 16-18, 2000.
NZ society for earthquake engineering reconnaissance team to Seattle, USA
Authors: Beetham Dick , Beattie Graeme , Earl Barry , Duncan Denzil
Published: January 2020

Our report describes the observations and assessments of the members of the reconnaissance team which visited Seattle, Tacoma, Olympia and surrounding areas a few days after the magnitude 6.8 Nisqually earthquake struck on 28 February, 2001. The report covers the tectonic setting and geology of the region, the source of the earthquake, its strong ground motions, ground damage - liquefaction and landslides, damage to buildings, bridges, lifelines, emergency management, community response, and lessons for New Zealand.
Earthquake hazard and risk assessment study for the Canterbury region, South Island, New Zealand
Authors: Kingsbury Peter A. , Pettinga Jarg R. , Van Dissen Russ J.
Published: January 2020

In recognition of the earthquake threat to Canterbury, and its statutory responsibilities, Environment Canterbury initiated a comprehensive, staged multi-year earthquake hazard and risk assessment study programme in 1997. In this paper the general framework and philosophy behind Environment Canterbury's Earthquake Hazard and Risk Assessment Programme is outlined. The results of the stage 1A earthquake source characterisation, and stage 1B probabilistic seismic hazard assessment for the Canterbury region are presented in companion papers in this volume. The programme participants have ongoing earthquake hazard research projects, and also are involved as practitioners in land-use planning and development of relevance to the Canterbury region. The coordinated programme is primarily designed to facilitate the integration of a diverse range of independent studies, so making relevant earthquake hazard and risk information readily available to a wide range of end-users, including other professionals (engineers and scientists), planners, civil defence and emergency management staff, utility operators, and developers. In addition the programme provides up to date, relevant information for public education and awareness purposes. The first stage of the programme has been completed, and includes identification and characterisation of earthquake sources, probabilistic hazard assessment, and formulation of earthquake scenarios. The long-term staged study programme will address the earthquake hazard, the risks posed, possible mitigation options and mitigation implementation methods available.
Earthquake source identification and characterisation for the Canterbury region, South Island, New Zealand
Authors: Pettinga Jarg R. , Yetton Mark D. , Van Dissen Russ J. , Downes Gaye
Published: January 2020

The Canterbury region of the South Island of New Zealand straddles a wide zone of active earth deformation associated with the oblique continent-continent collision between the Australian and Pacific tectonic plates east of the Alpine fault. The associated ongoing crustal strain is documented by the shallow earthquake activity (at depths of <40 km) and surface deformation expressed by active faulting, folding and ongoing geodetic strain. The level of earth deformation activity (and consequent earthquake hazard) decreases from the northwest to the southeast across the region. Deeper-level subduction related earthquake events are confined to the northernmost parts of the region, beneath Marlborough. To describe the geological setting and seismological activity in the region we have sub-divided the Canterbury region into eight domains that are defined on the basis of structural styles of deformation. These eight domains provide an appropriate geological and seismological context on which seismic hazard assessment can be based. A further, ninth source domain is defined to include the Alpine fault, but lies outside the region. About 90 major active earthquake source faults within and surrounding the Canterbury region are characterised in terms of their type (sense of slip), geometry (fault dimensions and attitude) and activity (slip rates, single event displacements, recurrence intervals, and timing of last rupture). In the more active, northern part of the region strike-slip and oblique strike-slip faults predominate, and recurrence intervals range from 81 to >5,000 years. In the central and southern parts of the region oblique-reverse and reverse/thrust faults predominate, and recurrence intervals typically range from -2,500 to >20,000 years. In this study we also review information on significant historical earthquakes that have impacted on the region (e,g. Christchurch earthquakes 1869 and 1870; North Canterbury 1888; Cheviot 1902; Motunau 1922; Buller 1929; Arthurs Pass 1929 and 1994; and others), and the record of instrumental seismicity. In addition, data from available paleoseismic studies within the region are included; and we also evaluate large potential earthquake sources outside the Canterbury region that are likely to produce significant shaking within the region. The most important of these is the Alpine fault, which we include as a separate source domain in this study. The integrated geological and seismological data base presented in this paper provide the foundation for the probabilistic seismic hazard assessment for the Canterbury region, and this is presented in a following companion paper in this Bulletin (Stirling et al. this volume).
Probabilistic seismic hazard assessment of the Canterbury region, New Zealand
Authors: Stirling Mark , Pettinga Jarg , Berryman Kelvin , Yetton Mark
Published: January 2020

We present the main results of a probabilistic seismic hazard assessment of the Canterbury region recently completed for Environment Canterbury (formerly Canterbury Regional Council). We use the distribution of active faults and the historical record of earthquakes to estimate the levels of earthquake shaking (peak ground acceleration and response spectral accelerations) that can be expected across the Canterbury region with return periods of 150, 475 and 1000 years. The strongest shaking (e.g. 475 year peak ground accelerations of 0.7g or more) can be expected in the west and north to northwest of the Canterbury region, where the greatest concentrations of known active faults and historical seismicity are located. Site-specific analyses of eight towns and cities selected by Environment Canterbury show that Arthur's Pass and Kaikoura are located within these zones of high hazard. In contrast, the centres studied in the Canterbury Plains (Rangiora, Kaiapoi, Christchurch, Ashburton, Temuka and Timaru) are generally located away from the zones of highest hazard. The study represents the first application of recently-developed methods in probabilistic seismic hazard at a regional scale in New Zealand.
An assessment of parameters describing the response of a reinforced concrete beam
Authors: Ingham J.M. , Liddell D. , Davidson B.J.
Published: January 2020

This paper outlines the background to a variety of parameters that are considered in order to establish their suitability as performance descriptors. This assessment is made in conjunction with data collected from twelve tests on nominally identical beam plastic hinges that were tested using different loading histories. Candidate descriptors are categorised as those that consider displacements and those based on damage. A suite of damage indices is also considered. Preliminary comments are made regarding the response comparison of tests conducted using different loading histories.
A two-dimensional study on the weak-motion seismic response of the Aburra Valley, Medellin, Colombia
Authors: Adams Brian M. , Jaramillo Juan Diego
Published: January 2020

A two-dimensional elastic finite-element method is used to investigate the weak-motion seismic response of the Aburra Valley of Medellin, Colombia. A vertically propagating anti- plane SH Ricker wavelet is used to study the response of the valley for frequencies up to 5 Hz. The Aburra Valley is very large and geologically diverse. The -1200-metre-deep and -15- kilometre-wide valley is covered by a variable layer of soft soils averaging some 30 metres deep. The soils are mainly residual, alluvial or debris-flow deposits. The valley also contains a network of 24 strong-motion seismic recorders. A 49,900-element mesh of a cross-sectional model through the southern end of Medellin is analysed using the finite-element software package, Archimedes. The results are presented in both time and frequency domains. A similar one-dimensional finite-element method is used for comparison. It is found that while amplification often occurs at frequencies defined by a one-dimensional analysis, the level of amplification is often highly dependent on multi-dimensional effects. Local irregularities in the stratigraphy and topography at some sites have a significant effect on the seismic response. Site response may also be influenced strongly by sub-valley structures up to a few kilometres across, yet the influence of the valley as a whole is small. Poor correlation between modelling results and recorded data is probably due to a lack of site-specific detail within the model, and the limiting two-dimensional nature of the analysis.
Recent studies of historical earthquake-induced landsliding, ground damage, and MM intensity in New Zealand
Authors: Hancox G. T. , Perrin N. D. , Dellow G.D.
Published: January 2020

A study of landsliding caused by 22 historical earthquakes in New Zealand was completed at the end of 1997. The main aims of that study were to: (a) study the nature and extent of landsliding and other ground damage (sand boils, subsidence and lateral spreading due to soil liquefaction) caused by historical earthquakes; (b) determine relationships between landslide distribution and earthquake magnitude, epicentre, isoseismals, faulting, geology and topography; and (c) establish improved environmental response criteria and ground classes for assigning MM intensities and seismic hazard assessments in New Zealand.

Relationships developed from the study indicate that the minimum magnitude for earthquake-induced landsliding (EIL) in N.Z. is about M 5, with significant landsliding occurring at M 6 or greater. The minimum MM intensity for landsliding is MM6, while the most common intensities for significant landsliding are MM7-8. The intensity threshold for soil liquefaction in New Zealand was found to be MM7 for sand boils, and MMS for lateral spreading, although such effects may also occur at one intensity level lower in highly susceptible materials. The minimum magnitude for liquefaction phenomena in N.Z. is about M 6, compared to M 5 overseas where highly susceptible soils are probably more widespread.

Revised environmental response criteria (landsliding, subsidence, liquefaction-induced sand boils and lateral spreading) have also been established for the New Zealand MM Intensity Scale, and provisional landslide susceptibility Ground Classes developed for assigning MM intensities in areas where there are few buildings. Other new data presented include recent earthquake studies (e.g., Murchison 1929), a preliminary landslide size/frequency distribution for earthquakes over the last 150 years, and a preliminary EIL Opportunity and hazard model for New Zealand. Implications for earthquake-induced landsliding for seismic hazard assessments in New Zealand are briefly discussed. Suggestions are also made for future EIL research, including further studies of historical earthquakes, and large prehistoric landslides in the central Southern Alps, northwest Nelson, and Fiordland, to help determine past and future earthquake activity and hazard from active faults in those regions.
A model for MM intensities near large earthquakes
Authors: Smith Warwick D.
Published: January 2020

The attenuation model for Modified Mercalli intensities that is currently in use in New Zealand (Dowrick & Rhoades, 1999) was developed from the available intensity data from large local earthquakes in New Zealand, but it does not represent well the intensity patterns that are expected when large earthquakes occur on long faults (length 20 km or more). This is because very few such events have occurred in New Zealand in historical times.

An attempt to account for elongated source geometries has resulted in a model which provides a plausible extension to the Dowrick & Rhoades model. It also addresses detail in the intensity data from New Zealand's four largest historical earthquakes, that has not previously been accounted for.

In development of the new model, stochastic terms have been added to represent the effects of asperities or areas of large slip on the rupture surface and to account for uncertainty in the fitting of the original data.
Damage ratios for low-rise non-domestic brick buildings in the magnitude 7.1 Wairarapa, New Zealand, earthquake of 24 June 1942
Authors: Dowrick D.J. , Rhoades D.A.
Published: January 2020

An analysis of damage costs to low-rise non-domestic brick buildings in the MM8 intensity zone of the Mw 7.1 Wairarapa earthquake of 24 June 1942 has evaluated the vulnerability of such buildings in New Zealand for the first time. The buildings studied were mostly of unreinforced brick of average workmanship and material quality, i.e. the second most vulnerable class of New Zealand buildings. Approximate vulnerabilities were also determined for partly reinforced and partly retrofitted buildings, and for one and two-storey buildings. The costs of damage were derived from insurance claims and local government records. The indicators of vulnerability that were determined were the statistical distributions and mean values of damage ratios, and the percentage of buildings damaged. Comparisons have also been made with results from studies of other earthquakes.
Reinforced concrete building performance in the Mw 7.8 1931 Hawke's Bay, New Zealand, earthquake
Authors: Vorstenbosch G. van de , Charleson A.W. , Dowrick D.J.
Published: January 2020

This paper examines the seismic performance of over half of the existing low-rise reinforced concrete buildings that survived the 3 February 1931 Hawke's Bay earthquake. Lateral resistance of these buildings is provided by reinforced concrete walls, unreinforced brick masonry infill frames and open reinforced concrete moment-resisting frames. Twenty-five buildings are analysed in both orthogonal directions for the lateral loads estimated to have occurred during the earthquake. The probable shear and bending strengths of structural members are compared to the maximum calculated seismic shear forces and bending moments. Wall restoring moments are compared to overturning moments. Whereas analyses suggest that most structures should have been severely damaged during the earthquake, in fact they performed well. In most cases no structural damage to reinforced concrete members was reported. Asymmetric buildings performed about as well as symmetric buildings. Possible reasons for these observations are examined and it is recommended how current practice might reflect these findings. The paper also contributes to an approximate assessment procedure, based on ratios of structural cross-sectional area to ground floor area, and reports on the structural areas of buildings that performed well in the earthquake. The excellent seismic performance of reinforced concrete buildings during the 1931 Hawke's Bay earthquake suggests current earthquake engineering analyses of similar pre-1935 low-rise non-domestic reinforced concrete buildings may underrate their seismic performance.
Strut-and-tie computer modelling of reinforced concrete bridge portal frames
Authors: To N. H. T. , Ingham J.M. , Sritharan S.
Published: January 2020

Nonlinear inelastic force-displacement response envelopes of full-scale reinforced concrete bridge portal frames are predicted in this paper by representing the frame using strut-and-tie models. The nonlinear strut-and-tie analyses, which included the tension stiffening effect, were performed using the computer program Drain-2DX. Strut-and-tie analytical results were found to correlate satisfactorily with the experimental data and to provide superior prediction to that generated using conventional planar frame models.
A comparison of the seismic design requirements in the New Zealand Loadings Standard with other major design codes
Authors: Fenwick Richard , Lau David , Davidson Barry
Published: January 2020

A series of ductile moment resisting reinforced concrete frames are sized to meet the minimum seismic provisions of the New Zealand Loadings Standard, NZS 4203-1992, the Draft NZ/Australian Loadings Standard, the Uniform Building Code, UBC-1997, the International Building code, IBC 2000 (1998 draft) and Eurocode 8 (1998 draft). The results of the analyses allow valid comparisons to be made between the different codes. It is shown that comparisons of individual clauses can be misleading due to the many interactions that occur between clauses.

Comparative analyses were made for the buildings described above located in both high and low seismic regions. It is shown that the strength and stiffness requirements for both the New Zealand Loadings Standard and the Draft Standard are low compared with the other codes of practice in the high seismic zone. It is recommended that the required design strengths in the Draft NZ/Australian Standard be increased.