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Research papers, University of Canterbury Library

Hybrid broadband simulation methods typically compute high-frequency portion of ground-motions using a simplified-physics approach (commonly known as “stochastic method”) using the same 1D velocity profile, anelastic attenuation profile and site-attenuation (κ0) value for all sites. However, these parameters relating to Earth structure are known to vary spatially. In this study we modify this conventional approach for high-frequency ground-shaking by using site-specific input parameters (referred to as “site-specific”) and analyze improvements over using same parameters for all sites (referred to as “generic”). First, we theoretically understand how different 1D velocity profiles, anelastic attenuation profiles and site-attenuation (κ0) values affects the Fourier Acceleration Spectrum (FAS). Then, we apply site-specific method to simulate 10 events from the 2010-2011 Canterbury earthquake sequence to assess performance against the generic approach in predicting recorded ground-motions. Our initial results suggest that the site-specific method yields a lower simulation standard deviation than generic case.

Articles, UC QuakeStudies

A document outlining the history of the Townsend Telescope and Observatory at the Christchurch Arts Centre. The document was written by Karen Pollard, Associate Professor in the Department of Physics and Astronomy at the University of Canterbury.

Images, UC QuakeStudies

A photograph of the Townsend Telescope in the Observatory at the Christchurch Arts Centre. This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A photograph of the Townsend Telescope in the Observatory at the Christchurch Arts Centre. This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Articles, UC QuakeStudies

A copy of Stars in a Cluster, a book by the Department of Physics and Astronomy at the University of Canterbury. The book was published in 1996 and edited by W. Tobin and G.M. Evans. This PDF version was created in 2014.

Images, UC QuakeStudies

A photograph of the Townsend Telescope in the Observatory at the Christchurch Arts Centre. Graeme Kershaw, Technician at the University of Canterbury Department of Astronomy and Physics, is standing to the left. This image was used by Kershaw to identify the telescope's parts after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A photograph of the clock drive of the Townsend Telescope. The telescope is in the Observatory at the Christchurch Arts Centre. This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A photograph of the middle section of the Townsend Telescope. The telescope is in the Observatory at the Christchurch Arts Centre. This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A photograph of the Townsend Telescope. The telescope is in the Observatory at the Christchurch Arts Centre. A plate on the side reads, "T Cook & Sons, 1864, York & London". This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Research papers, University of Canterbury Library

This study explicitly investigates uncertainties in physics-based ground motion simulation validation for earthquakes in the Canterbury region. The simulations utilise the Graves and Pitarka (2015) hybrid methodology, with separately quantified parametric uncertainties in the comprehensive physics and simplified physics components of the model. The study is limited to the simulation of 148 small magnitude (Mw 3.5 – 5) earthquakes, with a point source approximation for the source rupture representations, which also enables a focus on a small number of relevant uncertainties. The parametric uncertainties under consideration were selected through sensitivity analysis, and specifically include: magnitude, Brune stress parameter and high frequency rupture velocity. Twenty Monte Carlo realisations were used to sample parameter uncertainties for each of the 148 events. Residuals associated with the following intensity measures: spectral acceleration, peak ground velocity, arias intensity and significant duration, were ascertained. Using these residuals, validation was performed through assessment of systematic biases in site and source terms from mixed-effects regression. Based on the results to date, initial standard deviation recommendations for parameter uncertainties, based on the Canterbury simulations have been obtained. This work ultimately provides an initial step toward explicit incorporation of modelling uncertainty in simulated ground motion predictions for future events, which will improve the use of simulation models in seismic hazard analysis. We plan to subsequently assess uncertainties for larger magnitude events with more complex ruptures, and events across a larger geographic region, as well as uncertainties due to path attenuation, site effects, and more general model epistemic uncertainties.

Images, UC QuakeStudies

A photograph of the middle section of the Townsend Telescope. The telescope is in the Observatory at the Christchurch Arts Centre. A plate on the side reads, "T Cook & Sons, 1864, York & London". This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A photograph of the middle section of the Townsend Telescope. The telescope is in the Observatory at the Christchurch Arts Centre. A plate on the side reads, "T Cook & Sons, 1864, York & London". This image was used by Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, to identify the telescope's parts after the 22 February 2011 earthquake.