scholarly journals Suggested extensions of the New Zealand strong motion accelerograph network

1979 ◽  
Vol 12 (3) ◽  
pp. 264-268
Author(s):  
J. B. Berrill
Keyword(s):  
New Zealand ◽  
Ground Motions ◽  
Tall Buildings ◽  
Strong Motion ◽  
Local Network ◽  
Ground Shaking ◽  
Major Earthquake

The principal aim of the present network of strong motion accelerographs is to record the response of structures to earthquakes, and instruments are concentrated in the larger cities where modern, tall buildings are found. However, the behaviour of structures during earthquakes is now comparatively well understood. At the present time, estimating design ground motions is the weakest part in the process of designing structures to resist earthquakes. There is a strong need for more recordings of ground shaking, particularly
sets of several accelerograms from single earthquakes. It is not certain that the present accelerograph network would capture any significant record of strong motion during a major earthquake in New Zealand; and the chance of a set of three or more strong accelerograms being recorded is quite small. It is recommended that 25 additional instruments be installed promptly, to fill the main gaps in the present network, and to extend the capacity of the existing local network in the Wellington area.

scholarly journals Empirical models for predicting lateral spreading and evaluation using New Zealand data

2008 ◽  
Vol 41 (1) ◽  
pp. 10-23 ◽  
Author(s):  
Jian Zhang ◽  
Dick Beetham ◽  
Grant Dellow ◽  
John X. Zhao ◽  
Graeme H. McVerry
Keyword(s):  
New Zealand ◽  
Strong Motion ◽  
Lateral Spreading ◽  
Attenuation Relations ◽  
Geotechnical Parameters ◽  
Ground Shaking ◽  
Aerial Photos ◽  
New Model ◽  
The Difference ◽  
Lateral Displacements

A New empirical model has been developed for predicting liquefaction-induced lateral spreading displacement and is a function of response spectral displacements and geotechnical parameters. Different from the earlier model of Zhang and Zhao (2005), the application of which was limited to Japan and California, the new model can potentially be applied anywhere if ground shaking can be estimated (by using local strong-motion attenuation relations). The new model is applied in New Zealand where the response spectral displacement is estimated using New Zealand strong-motion attenuation relations (McVerry et al. 2006). The accuracy of the new model is evaluated by comparing predicted lateral displacements with those which have been measured from aerial photos or the width of ground cracks at the Landing Road bridge, the James Street loop, the Whakatane Pony Club and the Edgecumbe road and rail bridges sites after the 1987 Edgecumbe earthquake. Results show that most predicted errors (defined as the ratio of the difference between the measured and predicted lateral displacements to the measured one) from the new model are less than 40%. When compared with earlier models (Youd et al. 2002, Zhang and Zhao 2005), the new model provides the lowest mean errors.

scholarly journals Uncertainties in attenuation relations for New Zealand seismic hazard analysis

1986 ◽  
Vol 19 (1) ◽  
pp. 28-39 ◽  
Author(s):  
G. H. McVerry
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Response Spectrum ◽  
Strong Motion ◽  
Seismic Hazard Analysis ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Ground Shaking ◽  
Acceleration Data

Probabilistic techniques for seismic hazard analysis have
come into vogue in New Zealand for both the assessment of major projects and the development and review of seismic design codes. However, there are considerable uncertainties in the modelling
 of the strong-motion attenuation, which is necessarily based largely on overseas data. An excellent agreement is obtained between an average 5% damped response spectrum for New Zealand alluvial sites in the 20 to 59 km distance range and 5.4 to 6.0 magnitude class and that given by a Japanese model. Unfortunately, this corresponds to only about half the amplitude levels of 150 year spectra relevant to code design. The much more rapid decay
of ground shaking with distance in New Zealand has led to a considerable modification based on maximum ground acceleration
data from the Inangahua earthquake of the distance-dependence
of the Japanese response spectra model. Less scatter in New Zealand data has resulted in adopting a lower standard deviation for the attenuation model, which is important in reducing the considerable "probabilistic enhancement" of the hazard estimates. Regional differences in attenuation shown by intensities are difficult to resolve from the strong-motion acceleration data, apart from lower accelerations in Fiordland.

scholarly journals The Mw 7.2 Fiordland earthquake of August 21, 2003

2003 ◽  
Vol 36 (4) ◽  
pp. 233-248 ◽  
Author(s):  
Martin Reyners ◽  
Peter McGinty ◽  
Simon Cox ◽  
Ian Turnbull ◽  
Tim O'Neill ◽  
...  
Keyword(s):  
New Zealand ◽  
Ground Motions ◽  
Near Field ◽  
Strong Motion ◽  
Shallow Earthquake ◽  
Ground Acceleration ◽  
Attenuation Relationships ◽  
Steep Slopes ◽  
Epicentral Region ◽  
Shallow Part

The Mw 7.2 Fiordland earthquake of August 21 2003 was the largest shallow earthquake to occur in New Zealand for 35 years. Because of its location in an unpopulated area, it caused only minor damage to buildings, roads and infrastructure. It triggered numerous landslides on steep slopes in the epicentral region, where intensities reached MM9. Deployments of portable seismographs, strong motion recorders and GPS receivers in the epicentral region immediately after the event have established that the earthquake involved thrusting at the shallow part of the subduction interface between the Australian and Pacific plates. Recently installed strong motion recorders of the GeoNet network have ensured that the earthquake is New Zealand's best recorded subduction interface event. Microzonation effects are clear in some of the records. Current peak ground acceleration attenuation relationships for New Zealand subduction interface earthquakes underprediet the ground motions recorded during the earthquake, as was the case for previous large events in Fiordland in 1993 and 1989. The four portable strong motion recorders installed in the epicentral region have provided excellent near-field data on the larger aftershocks, with recorded peak ground accelerations ranging up to 0.28g from a nearby ML 6.1 event.

scholarly journals Distribution of scatter in New Zealand accelerograph data

1985 ◽  
Vol 18 (2) ◽  
pp. 151-164
Author(s):  
J. B. Berrill
Keyword(s):  
New Zealand ◽  
Ground Motions ◽  
Strong Motion ◽  
Natural Period ◽  
Data Set ◽  
Mean Values ◽  
Yield Values ◽  
Random Manner ◽  
Predicted Values ◽  
High Level

This study examines the currently available set of 22 New Zealand strong motion accelerograms to determine values of the scatter parameters for use in correcting for attenuation uncertainty in seismic hazard analyses. In particular, scatter of observed acceleration response spectral ordinates about mean values predicted by the attenuation law of Katayama, Iwaski and Seaki is investigated. It is found that to a high level of statistical significancef the observed spectral ordinates are log-normally distributed about the predicted values. For the data as a whole, lumping samples from the nine natural periods studied, the standard deviation of the logarithmic residuals is σ10=0.25. However, values ofσ10 for distinct natural periods are quite scattered in an apparently random manner, suggesting that the set of accelerograms is not large enough to yield stable results on a period-by-period basis. Furthermore, since there is no recording of severely damaging ground motions amongst the accelerograms, it is not clear that the value of σ10=0.25 is characteristic of hazardous ground motions in New Zealand, especially when it is compared with the value of 0.3 obtained from the more extensive Japanese data set. For immediate practical purposes, it is proposed that scatter parameters obtained from a combined New Zealand-Japanese data set be used. These records taken together yield values of σ10 increasing from 0.28 at a natural period of 0.1s to 0.32 at 1.0 seconds and above. Employing these values rather than σ10 = 0.25, results in a 20 percent increase in the peak of the 150-year uniform risk spectrum for Wellington.

Simulation of Pulse-Like Ground Motions during the 2015 Mw 8.3 Illapel Earthquake with a New Source Model Using Corrected Empirical Green’s Functions

2021 ◽  
Author(s):  
Claudio Fernández ◽  
Atsushi Nozu ◽  
Jorge G. F. Crempien ◽  
Juan Carlos de la Llera
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Response Spectra ◽  
Source Model ◽  
Primary Objective ◽  
Pulse Generation ◽  
Local Network ◽  
Generalized Inversion Technique ◽  
Wide Range ◽  
Illapel Earthquake

Abstract Pulse-like near-source ground motions were observed by the local network during the 2015 Mw 8.3 Illapel, Chile earthquake. Such ground motions can be quite damaging to a wide range of infrastructures. The primary objective of this study is to provide a source model that can explain such ground motions. The isolated nature of the pulses indicated that the rupture of some small isolated region on the fault contributed to the generation of the pulse. Therefore, we considered such regions and termed them as Strong Motion Pulse Generation Areas (SPGAs). We used the corrected empirical Green's function (EGF) method because this method has been successfully applied to near-source pulse-like ground motions in previous studies. We simulated synthetic waveforms using the frequency dependent quality factor Q=239f0.71 and empirical site amplification factors, which we obtained by applying a generalized inversion technique to local weak-motion data. The result indicated that the observed ground motions from the Mw 8.3 Illapel earthquake can readily be explained with a source model that involves two SPGAs with dimensions of several kilometers in spite of the huge rupture zone of the earthquake. The source model can reproduce velocity waveforms, acceleration Fourier amplitude spectra (FAS) and pseudoacceleration response spectra. It also reproduces the duration of strong ground motions quite accurately. No significant bias was found with respect to distance and frequency. In conclusion, the corrected EGF method is a very efficient tool to simulate near-source ground motions of a subduction earthquake when it is combined with higher stress-drop subevents whose sizes are adjusted to the observed pulse widths.

scholarly journals Strategies for strong motion earthquake recording in New Zealand

1979 ◽  
Vol 12 (3) ◽  
pp. 269-272
Author(s):  
W. R. Stephenson
Keyword(s):  
New Zealand ◽  
High Probability ◽  
High Reliability ◽  
New Technology ◽  
Strong Motion ◽  
Seismic Region ◽  
Major Earthquake ◽  
Processing Times ◽  
Self Testing ◽  
Future Strategy

The problem of how to record future strong earthquakes in New Zealand is examined by considering what data is required, how effective the present network will be in gathering that data, and what new technology is now available. It is concluded that present methods result in an unsatisfactory use of funds. There is a current emphasis on frequent expert servicing which, while it leads to a high probability of any recorder operating, restricts the number of installations able to be serviced. Thus we have a high probability of any given recorder working, coupled with a small probability of any given earthquake being within range of a recorder. The suggested future strategy is to first develop a new accelerograph of high reliability and the capability of self testing. This would incorporate a non volatile no moving parts electronic memory. Servicing of this would be at infrequent intervals, but a program of reporting the self test results by postcard would be adopted. By thus cutting down on recorder servicing and record processing times, we could force the major factor to be capital cost, and thus allow the network to expand until a realistic probability of recording a major earthquake was reached. The installation of about 70 additional strong motion accelerographs in the main seismic region would allow a good chance of recording our next major earthquake.

scholarly journals Strong motion records of the Milford Sound earthquake 1976 May 4

1978 ◽  
Vol 11 (3) ◽  
pp. 184-190 ◽  
Author(s):  
S. B. Hodder ◽  
R. I. Skinner ◽  
R. T. Hefford ◽  
P. M. Randal
Keyword(s):  
New Zealand ◽  
Ground Motions ◽  
Strong Motion ◽  
Strong Motion Records ◽  
Strong Motion Network

The strong-motion records obtained during the Milford Sound earthquake of 4 May 1976 are of particular interest since the assigned intensities are exceptionally low for an earthquake of magnitude 7. The recorded ground motions are presented here in the general format proposed for publication
of significant earthquakes recorded by the New Zealand strong-motion network. It is seen that the ground motions are consistent with the low intensities assigned.

scholarly journals Response of low-rise buildings to moderate ground shaking, particularly the May 1990 Weber earthquake

1994 ◽  
Vol 27 (3) ◽  
pp. 205-221
Author(s):  
S. Sritharan ◽  
D. J. Dowrick
Keyword(s):  
New Zealand ◽  
Seismic Performance ◽  
Ground Motions ◽  
Time History ◽  
Imperial Valley ◽  
Ground Shaking ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Spectral Accelerations

In the Weber earthquake of 13 May 1990 the stronger component of the ground motions recorded in Dannevirke was similar in strength to the El Centro S00E record from the 1940 Imperial Valley earthquake which underlies the New Zealand loadings code, The Modified Mercalli intensity in Dannevirke however was only about MM7 1⁄2, whereas the intensity corresponding to the 1984 earthquake code is about MM8 1⁄2 for the Dannevirke area. This paper compares the strength of the Dannevirke record in terms of spectral accelerations with (i) the above El Centro record, (ii) the Matahina dam record of the 1987 Edgecumbe earthquake, and (iii) the loadings of the 1984 and 1992 New Zealand codes. Also described in the paper are time-history analyses of one- and two- storey buildings subjected to the above ground motions in an attempt to explain why the damage levels were lower than might be expected from the strength of the recorded accelerograms. Comparisons are made of the seismic performance of moment-resisting frames and walled structures. Comments are made on two of the provisions of the 1992 loadings code.

scholarly journals Representative ground-motion ensembles for several major earthquake scenarios in New Zealand

2014 ◽  
Vol 47 (4) ◽  
pp. 231-252 ◽  
Author(s):  
Karim Tarbali ◽  
Brendon A. Bradley
Keyword(s):  
New Zealand ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Ground Motions ◽  
Conditional Intensity ◽  
Intensity Measure ◽  
Earthquake Scenarios ◽  
Major Earthquake ◽  
The Mean ◽  
Representative Ground

In this paper, representative ground motion ensembles for several major earthquake scenarios in New Zealand are developed. Cases considered include representative ground motions for the occurrence of Alpine, Hope and Porters Pass earthquakes in Christchurch city, and the occurrence of Wellington, Wairarapa and Ohariu fault ruptures in Wellington city. For each considered scenario rupture, ensembles of 20 and 7 ground motions are selected using the generalized conditional intensity measure (GCIM) approach, ensuring that the ground motion ensembles represent both the mean and distribution of ground motion intensity which such scenarios could impose. These scenario-based ground motion sets can be used to complement ground motions which are often selected in conjunction with probabilistic seismic hazard analysis, in order to understand the performance of structures for the question “what if this fault ruptures?”

Comparison of earthquake and microtremor ground motions in El Centro, California

1973 ◽  
Vol 63 (4) ◽  
pp. 1227-1253 ◽  
Author(s):  
F. E. Udwadia ◽  
M. D. Trifunac
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Strong Motion ◽  
Site Conditions ◽  
Ground Shaking ◽  
Response Characteristics ◽  
Local Site ◽  
Simple Features ◽  
Low Amplitude ◽  
Local Site Conditions

abstract Strong earthquake ground shaking has been investigated by the study of 15 events recorded in El Centro, California. The strong-motion records analyzed show that no simple features (e.g., local site conditions) govern the details of local ground shaking. Any effects of local subsoil conditions at this site appear to be overshadowed by the source mechanism and the transmission path, there being no distinctly identifiable site periodicities. Microtremor measurements have been taken in the area surrounding the strong-motion site. The objective was an investigation of possible correlations with strong ground motions and the analysis of site-response characteristics. Basic difficulties in ascertaining local site conditions through such low-amplitude ground motions are illustrated. It has been found that in this area microtremor and earthquake processes are widely different in character, there being little to no correlation between the ground's response to earthquakes and to microtremor excitations. Microtremors have been found to be nonstationary over periods of about a day or so, introducing further uncertainties into inferences from such measurements.

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