scholarly journals Systematic Ground Motion Observations in the Canterbury Earthquakes and Region-Specific Non-Ergodic Empirical Ground Motion Modeling

2015 ◽  
Vol 31 (3) ◽  
pp. 1735-1761 ◽  
Author(s):  
Brendon A. Bradley
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Strong Motion ◽  
Central Business District ◽  
Motion Modeling ◽  
Strong Motion Station ◽  
Systematic Effects ◽  
Canterbury Earthquake Sequence ◽  
Business District ◽  
A Site

This paper presents an examination of ground motion observations from 20 near-source strong motion stations during the most significant ten events in the 2010–2011 Canterbury earthquake sequence to examine region-specific systematic effects based on relaxing the conventional ergodic assumption. On the basis of similar site-to-site residuals, surfical geology, and geographical proximity, 15 of the 20 stations are grouped into four sub-regions: the Central Business District; and Western, Eastern, and Northern suburbs. Mean site-to-site residuals for these sub-regions then allows for the possibility of non-ergodic ground motion prediction over these sub-regions of Canterbury, rather than only at strong motion station locations. The ratio of the total non-ergodic vs. ergodic standard deviation is found to be, on average, consistent with previous studies, however it is emphasized that on a site-by-site basis the non-ergodic standard deviation can easily vary by ±20%.

scholarly journals A Non-Ergodic Effective Amplitude Ground-Motion Model for California

2021 ◽  
Author(s):  
Grigorios Lavrentiadis ◽  
Norman A. Abrahamson ◽  
Nicolas M. Kuehn
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Amplitude Spectrum ◽  
Time History ◽  
Motion Model ◽  
Small Magnitude ◽  
Varying Coefficients ◽  
Ground Motion Model ◽  
Systematic Effects

Abstract A new non-ergodic ground-motion model (GMM) for effective amplitude spectral (EAS) values for California is presented in this study. EAS, which is defined in Goulet et al. (2018), is a smoothed rotation-independent Fourier amplitude spectrum of the two horizontal components of an acceleration time history. The main motivation for developing a non-ergodic EAS GMM, rather than a spectral acceleration GMM, is that the scaling of EAS does not depend on spectral shape, and therefore, the more frequent small magnitude events can be used in the estimation of the non-ergodic terms. The model is developed using the California subset of the NGAWest2 dataset Ancheta et al. (2013). The Bayless and Abrahamson (2019b) (BA18) ergodic EAS GMM was used as backbone to constrain the average source, path, and site scaling. The non-ergodic GMM is formulated as a Bayesian hierarchical model: the non-ergodic source and site terms are modeled as spatially varying coefficients following the approach of Landwehr et al. (2016), and the non-ergodic path effects are captured by the cell-specific anelastic attenuation attenuation following the approach of Dawood and Rodriguez-Marek (2013). Close to stations and past events, the mean values of the non-ergodic terms deviate from zero to capture the systematic effects and their epistemic uncertainty is small. In areas with sparse data, the epistemic uncertainty of the non-ergodic terms is large, as the systematic effects cannot be determined. The non-ergodic total aleatory standard deviation is approximately 30 to 40% smaller than the total aleatory standard deviation of BA18. This reduction in the aleatory variability has a significant impact on hazard calculations at large return periods. The epistemic uncertainty of the ground motion predictions is small in areas close to stations and past event.

scholarly journals Dead Among the Living: Burning Bodies in Inner City Wellington

2021 ◽  
Author(s):  
◽  
Zoe Jaye Moller
Keyword(s):  
Methodological Approach ◽  
Central Business District ◽  
Urban Life ◽  
Western Society ◽  
Urban Context ◽  
Life And Death ◽  
Everyday Lives ◽  
The Dead ◽  
Business District ◽  
A Site

<p>The architecture of cremation has struggled to embrace an identity; it has remained ambiguous in its architectural typology and religious association since it was first introduced into western society. Additionally, the absence of a ritual place for death in urban life is one manifestation of the contemporary idea that death does not belong in the modern living city. Death is seen as having no place in a society obsessed with youth and vigour; it has become an architectural taboo. The increased reluctance to physically address death as the inevitable consequence to life has resulted in death associated architecture eroding to the point where it has become absent in our everyday lives.   With the expansion of Wellington during the 1800’s, cemeteries formerly on the outskirts (Mount and Bolton Streets) became engulfed by the sprawling city. Overflowing with corpses by the 1900’s, these sites now remain dormant, eliminating any opportunity for the public to ‘see’ death daily. Situating a crematorium within a Wellington urban context will not only address this issue, but also successfully meet the demand for more burial spaces, as Makara Cemetery is nearing capacity, and Karori Cemetery is already full. A site located in the ‘dead centre’ of Wellington’s central business district becomes the testing ground for a new urban crematorium – one that aims to reduce the anxiety around death by inclusion of it within people’s everyday lives. It aims to provide mourners with a more meaningful experience, and the general public a cosmopolitan necropolis. The presence of an urban crematorium and columbarium provides continual opportunities for people to reflect on their own mortality, honour and remember the dead, and be reminded to live while they can.   A methodological approach of testing architectural sequences in relation to pattern language theory will allow for a thematic progression for mourners from sorrow to acceptance through the use of light, shadow, and sectional arrangements. This investigation into the meaningfulness of relationships between people and buildings, life and death, translates into spaces ready to be further invested with meaning by mourners.</p>

scholarly journals On the modeling of strong motion parameters and correlation with historical macroseismic data: an application to the 1915 Avezzano earthquake

1995 ◽  
Vol 38 (5-6) ◽  
Author(s):  
R. Berardi ◽  
A. Mendez ◽  
M. Mucciarelli ◽  
F. Pacor ◽  
G. Longhi ◽  
...  
Keyword(s):  
Ground Motion ◽  
Goodness Of Fit ◽  
Strong Motion ◽  
Seismic Energy ◽  
Rupture Process ◽  
Macroseismic Data ◽  
Motion Modeling ◽  
Ground Shaking ◽  
Acceleration Time Histories ◽  
Motion Parameters

This article describes the results of a ground motion modeling study of the 1915 Avezzano earthquake. The goal was to test assuinptions regarding the rupture process of this earthquake by attempting to model the damage to historical monuments and populated habitats during the earthquake. The methodology used combines stochastic and deterministic modeling techniques to synthesize strong ground motion, starting from a simple characterization of the earthquake source on an extended fault plane. The stochastic component of the methodology is used to simulate high-frequency ground motion oscillations. The envelopes of these synthetic waveforms, however, are simulated in a deterministic way based on the isochron formulation for the calculation of radiated seismic energy. Synthetic acceleration time histories representative of ground motion experienced at the towns of Avezzano, Celano, Ortucchio, and Sora are then analyzed in terms of the damage to historical buildings at these sites. The article also discusses how the same methodology can be adapted to efficiently evaluate various strong motion parameters such as duration and amplitude of ground shaking, at several hundreds of surface sites and as a function of rupture process. The usefulness of such a technique is illustrated through the inodeling of intensity data from the Avezzano earthquake. One of the most interesting results is that it is possible to distinguish between different rupture scenarios for the 1915 earthquake based on the goodness of fit of theoretical intensities to observed values.

scholarly journals Soil profile characterisation of Christchurch Central Business District strong motion stations

2015 ◽  
Vol 48 (3) ◽  
pp. 146-156 ◽  
Author(s):  
Liam M. Wotherspoon ◽  
Rolando P. Orense ◽  
Brendon A. Bradley ◽  
Brady R. Cox ◽  
Clinton M. Wood ◽  
...  
Keyword(s):  
Soil Profile ◽  
Site Response ◽  
Strong Motion ◽  
Central Business District ◽  
Site Classification ◽  
Surface Wave Dispersion ◽  
Close Vicinity ◽  
Short Period ◽  
Business District ◽  
Site Classes

This paper presents an overview of the soil profile characteristics at strong motion station (SMS) locations in the Christchurch Central Business District (CBD) based on recently completed geotechnical site investigations. Given the variability of Christchurch soils, detailed investigations were needed in close vicinity to each SMS. In this regard, CPT, SPT and borehole data, and shear wave velocity (Vs) profiles from surface wave dispersion data in close vicinity to the SMSs have been used to develop detailed representative soil profiles at each site and to determine site classes according to the New Zealand standard NZS1170.5. A disparity between the NZS1170.5 site classes based on Vs and SPT N60 investigation techniques is highlighted, and additional studies are needed to harmonize site classification based on these techniques. The short period mode of vibration of soft deposits above gravels, which are found throughout Christchurch, are compared to the long period mode of vibration of the entire soil profile to bedrock. These two distinct modes of vibration require further investigation to determine their impact on the site response. According to current American and European approaches to seismic site classification, all SMSs were classified as problematic soil sites due to the presence of liquefiable strata, soils which are not directly accounted for by the NZS1170.5 approach.

scholarly journals Dead Among the Living: Burning Bodies in Inner City Wellington

2021 ◽  
Author(s):  
◽  
Zoe Jaye Moller
Keyword(s):  
Methodological Approach ◽  
Central Business District ◽  
Urban Life ◽  
Western Society ◽  
Urban Context ◽  
Life And Death ◽  
Everyday Lives ◽  
The Dead ◽  
Business District ◽  
A Site

<p>The architecture of cremation has struggled to embrace an identity; it has remained ambiguous in its architectural typology and religious association since it was first introduced into western society. Additionally, the absence of a ritual place for death in urban life is one manifestation of the contemporary idea that death does not belong in the modern living city. Death is seen as having no place in a society obsessed with youth and vigour; it has become an architectural taboo. The increased reluctance to physically address death as the inevitable consequence to life has resulted in death associated architecture eroding to the point where it has become absent in our everyday lives.   With the expansion of Wellington during the 1800’s, cemeteries formerly on the outskirts (Mount and Bolton Streets) became engulfed by the sprawling city. Overflowing with corpses by the 1900’s, these sites now remain dormant, eliminating any opportunity for the public to ‘see’ death daily. Situating a crematorium within a Wellington urban context will not only address this issue, but also successfully meet the demand for more burial spaces, as Makara Cemetery is nearing capacity, and Karori Cemetery is already full. A site located in the ‘dead centre’ of Wellington’s central business district becomes the testing ground for a new urban crematorium – one that aims to reduce the anxiety around death by inclusion of it within people’s everyday lives. It aims to provide mourners with a more meaningful experience, and the general public a cosmopolitan necropolis. The presence of an urban crematorium and columbarium provides continual opportunities for people to reflect on their own mortality, honour and remember the dead, and be reminded to live while they can.   A methodological approach of testing architectural sequences in relation to pattern language theory will allow for a thematic progression for mourners from sorrow to acceptance through the use of light, shadow, and sectional arrangements. This investigation into the meaningfulness of relationships between people and buildings, life and death, translates into spaces ready to be further invested with meaning by mourners.</p>

Partitioning Ground Motion Uncertainty When Conditioned on Station Data

2022 ◽  
Author(s):  
Davis T. Engler ◽  
C. Bruce Worden ◽  
Eric M. Thompson ◽  
Kishor S. Jaiswal
Keyword(s):  
Ground Motion ◽  
Strong Motion ◽  
Macroseismic Intensity ◽  
Observational Constraints ◽  
Ground Shaking ◽  
Ground Failure ◽  
Strong Motion Station ◽  
Station Data ◽  
Uncertainty Estimates ◽  
The World

ABSTRACT Rapid estimation of earthquake ground shaking and proper accounting of associated uncertainties in such estimates when conditioned on strong-motion station data or macroseismic intensity observations are crucial for downstream applications such as ground failure and loss estimation. The U.S. Geological Survey ShakeMap system is called upon to fulfill this objective in light of increased near-real-time access to strong-motion records from around the world. Although the station data provide a direct constraint on shaking estimates at specific locations, these data also heavily influence the uncertainty quantification at other locations. This investigation demonstrates methods to partition the within- (phi) and between-event (tau) uncertainty estimates under the observational constraints, especially when between-event uncertainties are heteroscedastic. The procedure allows the end users of ShakeMap to create separate between- and within-event realizations of ground-motion fields for downstream loss modeling applications in a manner that preserves the structure of the underlying random spatial processes.

scholarly journals Ground Motion and Seismic Source Aspects of the Canterbury Earthquake Sequence

2014 ◽  
Vol 30 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Brendon A. Bradley ◽  
Mark C. Quigley ◽  
Russ J. Van Dissen ◽  
Nicola J. Litchfield
Keyword(s):  
Ground Motion ◽  
Agricultural Land ◽  
Source Region ◽  
High Stress ◽  
Central Business District ◽  
Seismic Source ◽  
Vertical Displacement ◽  
Earthquake Sequence ◽  
River Channels ◽  
Canterbury Earthquake Sequence

This paper provides an overview of the ground motion and seismic source aspects of the Canterbury earthquake sequence. Common reported attributes among the largest earthquakes in this sequence are complex ruptures, large displacements per unit fault length, and high stress drops. The Darfield earthquake produced an approximately 30 km surface rupture in the Canterbury Plains with dextral surface displacements of several meters, and a subordinate amount of vertical displacement, impacting residential structures, agricultural land, and river channels. The dense set of strong ground motions recorded in the near-source region of all the major events in the sequence provides significant insight into the spatial variability in ground motion characteristics, as well as the significance of directivity, basin-generated surface waves, and nonlinear local site effects. The ground motion amplitudes in the 22 February 2011 earthquake, in particular, produced horizontal ground motion amplitudes in the Central Business District (CBD) well above those specified for the design of conventional structures.

Liquefaction Effects on Buildings in the Central Business District of Christchurch

2014 ◽  
Vol 30 (1) ◽  
pp. 85-109 ◽  
Author(s):  
Jonathan Bray ◽  
Misko Cubrinovski ◽  
Joshua Zupan ◽  
Merrick Taylor
Keyword(s):  
Earthquake Engineering ◽  
Central Business District ◽  
Earthquake Sequence ◽  
Ground Settlement ◽  
Cone Penetration ◽  
Multistory Buildings ◽  
Canterbury Earthquake Sequence ◽  
Business District ◽  
Performance Based Earthquake Engineering ◽  
Ground Settlements

The Canterbury earthquake sequence provides an exceptional opportunity to investigate the effects of varying degrees of liquefaction on the built environment. Many multistory buildings in the Central Business District were heavily damaged by liquefaction-induced ground movements during the Christchurch earthquake, but not by other earthquakes (e.g., the Darfield and June 2011 events). Cone penetration test (CPT)–based liquefaction triggering evaluations were conservative. The conservatism in the liquefaction triggering assessments led to post-liquefaction ground settlement estimates that were generally similar for the large events in the earthquake sequence, whereas significant ground settlements and building damage in the CBD were only observed for the Christchurch earthquake. Moreover, the liquefaction-induced ground settlement procedures do not capture important shear-induced deformation mechanisms and the effects of ground loss due to sediment ejecta. Performance-based earthquake engineering requires improved procedures to capture the differing levels of performance observed in Christchurch.

The ShakeOut Earthquake Source and Ground Motion Simulations

2011 ◽  
Vol 27 (2) ◽  
pp. 273-291 ◽  
Author(s):  
Robert W. Graves ◽  
Brad T. Aagaard ◽  
Kenneth W. Hudnut
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Peak Ground Velocity ◽  
Motion Modeling ◽  
Ground Acceleration ◽  
San Andreas ◽  
Basin Effects ◽  
Simulated Ground Motions ◽  
D Model

The ShakeOut Scenario is premised upon the detailed description of a hypothetical Mw 7.8 earthquake on the southern San Andreas Fault and the associated simulated ground motions. The main features of the scenario, such as its endpoints, magnitude, and gross slip distribution, were defined through expert opinion and incorporated information from many previous studies. Slip at smaller length scales, rupture speed, and rise time were constrained using empirical relationships and experience gained from previous strong-motion modeling. Using this rupture description and a 3-D model of the crust, broadband ground motions were computed over a large region of Southern California. The largest simulated peak ground acceleration (PGA) and peak ground velocity (PGV) generally range from 0.5 to 1.0 g and 100 to 250 cm/s, respectively, with the waveforms exhibiting strong directivity and basin effects. Use of a slip-predictable model results in a high static stress drop event and produces ground motions somewhat higher than median level predictions from NGA ground motion prediction equations (GMPEs).

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