scholarly journals Highlights of 30 years 
of strong-motion recording in New Zealand

1993 ◽  
Vol 26 (4) ◽  
pp. 375-389 ◽  
Author(s):  
W. J. Cousins
Keyword(s):  
New Zealand ◽  
Soil Structure ◽  
Soft Soil ◽  
Broad Band ◽  
Strong Motion ◽  
Moderate Intensity ◽  
Wide Range ◽  
Peak Ground Accelerations ◽  
Spectral Accelerations ◽  
Strong Motion Recording

Strong-motion recording has been carried out in New Zealand for somewhat more than 30 years. The largest network of instruments, comprising 220 accelerographs and 72 scratch-plate acceleroscopes, is operated by the Institute of Geological and Nuclear Sciences. During the last 30 years the IGNS network has yielded a little over 2000 records, 1600 of which have been matched with earthquake events to give a substantial body of New Zealand data that is currently being used in studies of attenuation and microzonation. The highest peak ground accelerations recorded to date on scratch-plates and accelerographs are respectively 0.6g (from Reefton during the 1968 Inangahua earthquake) and 0.4g (from Dannevirke from the Weber earthquake of 13th May 1990). About 300 of the more significant accelerograms have been digitized and computer processed to give data sets suitable for use in aseismic structural design, and studies of the attenuation of spectral acceleration, soil-structure interactions, structural responses, and microzonation. Peak ground accelerations from New Zealand earthquakes appear to be stronger, over a wide range of source distances, than predicted from attenuation models applicable to the Western USA. Spectral accelerations in New Zealand appear to modelled well by a model based on Japanese data, but some caution is needed as the New Zealand data base of spectral accelerations is small and deficient in near source data from moderate to large earthquakes. Strong-motion records from deep or soft soil sites, and from arrays of recorders in the Wellington region, have shown both resonant and broad-band amplification for rock input motions of small to moderate intensity. Sets of records from arrays of accelerographs in three medium-rise buildings have revealed the effects of soil-structure interactions, and records from an array of 5 accelerographs on Matahina dam showed that part of the dam responded in a strongly nonlinear fashion during the 1987 Edgecumbe earthquake.

scholarly journals Peak ground accelerations recorded in the 1968 Inangahua earthquake and some attenuation implications

1993 ◽  
Vol 26 (3) ◽  
pp. 349-355 ◽  
Author(s):  
David J. Dowrick ◽  
S. Sritharan
Keyword(s):  
New Zealand ◽  
Strong Motion ◽  
Strong Motion Data ◽  
Western Usa ◽  
Motion Data ◽  
Information Gap ◽  
Wide Range ◽  
Peak Ground Accelerations ◽  
Attenuation Models

The Ms 7.4 1968 Inangahua earthquake was the largest New Zealand earthquake to have occurred from 1934 to 1992. The valuable strong motion data obtained on scratchplate acceleroscopes has not previously been adequately described. Filling that information gap, this paper lists the re-evaluated peak ground accelerations and examines their attenuation properties. It is shown that the accelerations from this event are much stronger over a wide range of source distances than those obtained using attenuation models for the western USA. Similar results have been found for a number of more recent New Zealand events in another study.

scholarly journals Attenuation of peak ground accelerations in some recent New Zealand earthquakes

1993 ◽  
Vol 26 (1) ◽  
pp. 3-13 ◽  
Author(s):  
D. J. Dowrick ◽  
S. Sritharan
Keyword(s):  
New Zealand ◽  
Strong Motion ◽  
Medium Size ◽  
Data Sets ◽  
Fault Rupture ◽  
Motion Data ◽  
Peak Ground Accelerations ◽  
The Mean ◽  
Using Data ◽  
Event Based

The attenuation of peak ground accelerations was studied for eight New Zealand earthquakes which occurred in the period 1987 to 1991. These events were of medium size with moment magnitudes in the range Mw = 5.8 - 6.7, with depth to centroids of the fault rupture ranging from 4 to 60 km. Attenuation of peak ground accelerations was examined for each event, based on the slope distance from the rupture surface to each strong motion data site. The mean regression attenuation curve for each event was compared with those derived by others using data sets from other parts of the world, allowance being made for source mechanism and depth. Excepting the 1988 Te Anau event, the other seven New Zealand events as a set closely match a Japanese model, but give significantly stronger accelerations than those predicted by the models from western USA and Europe.

Near-Source Magnitude Scaling of Spectral Accelerations: Analysis and Update of Kotha et al. (2020) Model

2021 ◽  
Author(s):  
Sreeram Reddy Kotha ◽  
Graeme Weatherill ◽  
Dino Bindi ◽  
Fabrice Cotton
Keyword(s):  
Model Uncertainty ◽  
Soft Soil ◽  
Strong Motion ◽  
Motion Models ◽  
Magnitude Scaling ◽  
Short Period ◽  
Hazard And Risk ◽  
Spectral Accelerations ◽  
Parametric Analyses ◽  
A Site

Abstract Ground-motion models (GMMs) are often used to predict the random distribution of spectral accelerations (SAs) at a site due to an earthquake at a distance. In probabilistic seismic hazard and risk assessment, large earthquakes occurring close to a site are considered as critical scenarios. GMMs are expected to perform well for such rare scenarios i.e., to predict realistic SAs with low prediction uncertainty. However, the datasets used to regress GMMs are usually deficient of data from rare/critical scenarios. The Kotha et al. (2020) GMM developed from the Engineering Strong Motion (ESM) dataset was found to predict decreasing short-period SAs with increasing \({M}_{W}\ge {M}_{h}=6.2\), and with large within-model uncertainty at near-source distances \({R}_{JB}\le 30km\). In this study, we analysed and updated the parametrisation of the GMM based on non-parametric and parametric analyses of ESM and the NEar Source Strong motion (NESS) datasets. By reducing \({M}_{h}\) to 5.7, we could rectify the \({M}_{W}\) scaling issue, while also reducing the within-model uncertainty on predictions at \({M}_{W}\ge 6.2\). We then evaluated the updated GMM against NESS data, and found that the SAs from a few large, thrust-faulting events in California, New Zealand, Japan, and Mexico are significantly higher than GMM median predictions. However, near-source recordings of these events were mostly made on soft-soil geology and contain anisotropic pulse-like effects. A more thorough non-ergodic treatment of NESS was not possible because most sites sampled unique events in very diverse tectonic environments. Therefore, for now, we provide an updated set of GMM coefficients, within-model uncertainty, and heteroskedastic variance models.

scholarly journals Ormond earthquake liquefaction reconnaissance report

1993 ◽  
Vol 26 (3) ◽  
pp. 312-328 ◽  
Author(s):  
Steven A. Christensen
Keyword(s):  
New Zealand ◽  
Focal Depth ◽  
Strong Motion ◽  
North West ◽  
The North ◽  
Peak Ground Accelerations ◽  
Seismological Observatory

On August 10 1993, at 09h 46m UT an earthquake of magnitude (ML) 6.4 occurred near Ormond, a locality to the north west of Gisbome in the North Island of New Zealand. The epicentre of the event was 38.52°S, 177.93°E, and had a focal depth of 48 km (Seismological Observatory, Institute of Geological and Nuclear Sciences Ltd.). Strong motion accelerographs at two sites on sediment in Gisborne recorded peak ground accelerations of 0.22 g at a distance of 20 km from the epicentre, while at Wairoa (80 km to the SW of the epicentre) 0.05 g was recorded, at Tolaga Bay (30 km to the NE of the epicentre) 0.09 g was measured [Pers. Comn. J. Zhou], and strong motion lasted for 5-10 s. Intensity of MMVI was observed in the Ormond area with pockets of MMVII, the later being based in particular on the presence of liquefaction.

scholarly journals The 2003, Mw 7.2 Fiordland earthquake, and its near-source aftershock strong motion data

2004 ◽  
Vol 37 (3) ◽  
pp. 139-145
Author(s):  
P. McGinty
Keyword(s):  
New Zealand ◽  
Strong Motion ◽  
Data Set ◽  
Strong Motion Data ◽  
Preliminary Results ◽  
Motion Data ◽  
Magnitude Range ◽  
Source Data ◽  
Peak Ground Accelerations ◽  
Attenuation Models

The 2003 Fiordland earthquake was not only the best ever recorded subduction interface earthquake to occur in New Zealand, it also provided the opportunity to collect near-source strong-motion data produced by its aftershocks covering a wide magnitude range. Near source strong-motion data had been lacking in the New Zealand data set, on which current attenuation models are based. Here the author presents some preliminary results relating recorded peak ground accelerations in the near-source field to current attenuation models. The near-source data from the 2003 Fiordland earthquake sequence has shown that the observed data has a greater magnitude-dependence than that predicted by the current attenuation models. This new data will help to improve current models and will lead to a better understanding of the attenuation process associated with New Zealand subduction interface earthquakes.

Natural enemies of bridal creeper Asparagus asparagoides in New Zealand

2008 ◽  
Vol 61 ◽  
pp. 362-367
Author(s):  
H.M. Harman ◽  
N.W. Waipara ◽  
C.J. Winks ◽  
L.A. Smith ◽  
P.G. Peterson ◽  
...  
Keyword(s):  
New Zealand ◽  
Natural Enemies ◽  
Invertebrate Fauna ◽  
Classical Biocontrol ◽  
Wide Range

Bridal creeper is a weed of natural and productive areas in the northern North Island of New Zealand A classical biocontrol programme was initiated in 20052007 with a survey of invertebrate fauna and pathogens associated with the weed in New Zealand Although bridal creeper was attacked by a wide range of generalist invertebrates their overall damage affected

The Australia and New Zealand v Japan Southern Bluefin Tuna (Jurisdiction and Admissibility) Award of the First Law of the Sea Convention Annex VII Arbitral Tribunal

2001 ◽  
Vol 16 (2) ◽  
pp. 239-293 ◽  
Author(s):  
Barbara Kwiatkowska
Keyword(s):  
New Zealand ◽  
Bluefin Tuna ◽  
Fundamental Principle ◽  
Law Of The Sea ◽  
Arbitral Tribunal ◽  
Compulsory Arbitration ◽  
Wide Range ◽  
The Future ◽  
Questions And Answers ◽  
Southern Bluefin Tuna

AbstractThe Southern Bluefin Tuna (Jurisdiction and Admissihilily) Award of 4 August 2000 marked the first instance of the application of compulsory arbitration under Part XV, Section 2 of the 1982 UN Law of the Sea Convention and of the exercise by the Annex VII Tribunal of la compétence de la compétence pursuant to Article 288(4) over the merits of the instant dispute. The 72-paragraph Award is a decision of pronounced procedural complexity and significant multifaceted impacts of which appreciation requires an in-depth acquaintance with procedural issues of peaceful settlement of disputes in general and the-law-of-the-sea-related disputes in particular. Therefore, the article surveys first the establishment of and the course of proceedings before the five-member Annex VII Arbitral Tribunal, presided over by the immediate former ICJ President, Judge Stephen M. Schwebel, and also comprising Judges Keith, Yamada. Feliciano and Tresselt. Subsequently, the wide range of specific paramount questions and answers of the Tribunal are scrutinised against the background of arguments advanced by the applicants (Australia and New Zealand) and the respondent (Japan) during both written and oral pleadings, including in reliance on the extensive ICJ jurisprudence and treaty practice concerned. On this basis, the article turns to an appraisal of the impacts of the Arbitral Tribunal's paramount holdings and its resultant dismissal of jurisdiction with the scrupulous regard for the fundamental principle of consensuality. Amongst such direct impacts as between the parties to the instant case, the inducements provided by the Award to reach a successful settlement in the future are of particular importance. The Award's indirect impacts concern exposition of the paramount doctrine of parallelism between the umbrella UN Convention and many compatible (fisheries, environmental and other) treaties, as well as of multifaceted, both substantial and procedural effects of that parallelism. All those contributions will importantly guide other courts and tribunals seised in the future under the Convention's Part XV, Section 2.

The accuracy of soil response estimates using soil-to-rock spectral ratios

1996 ◽  
Vol 86 (2) ◽  
pp. 519-523
Author(s):  
Igor A. Beresnev ◽  
Kuo-Liang Wen
Keyword(s):  
Site Response ◽  
Soft Soil ◽  
Strong Motion ◽  
Finite Depth ◽  
Spectral Ratios ◽  
Site Specific ◽  
Soil Response ◽  
Strong Motion Records ◽  
The Real ◽  
Specific Amplification

Abstract Spectral ratios between soft soil and reference rock sites are often used to predict the sedimentary site response to earthquakes. However, their relationship with the genuine site-specific amplification function is often unclear. We compare the soil-to-rock spectral ratios between the stations that are 3.3 km apart with the “genuine” response given by the ratios between the surface and 17 and 47 m downhole. Data from the SMART1 array in Taiwan are used. The “weak” and “strong” motion records are addressed separately to allow for nonlinear soil response. The soil-to-rock spectral ratios are nearly identical to the “true” amplification at the frequencies from 1 to 10 Hz, if the finite depth of the borehole is taken into account. They correctly capture the strong-motion deamplification effect. However, the soil-to-rock spectral ratios are roughly 1.4 times more uncertain than surface-to-47-m ratios. In summary, the soil-to-rock spectral ratios can be considered as the reliable estimates of the real site response.

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