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We present ground motion simulations of the Porters Pass (PP) fault in the Canterbury region of New Zealand; a major active source near Christchurch city. The active segment of the PP fault has an inferred length of 82 km and a mostly strike-slip sense of movement. The PP fault slip makes up approximately 10% of the total 37 mm/yr margin-parallel plate motion and also comprises a significant proportion of the total strain budget in regional tectonics. Given that the closest segment of the fault is less than 45 km from Christchurch city, the PP fault is crucial for accurate earthquake hazard assessment for this major population centre. We have employed the hybrid simulation methodology of Graves and Pitarka (2010, 2015), which combines low (f<1 Hz) and high (f>1 Hz) frequencies into a broadband spectrum. We have used validations from three moderate magnitude events (𝑀𝑤4.6 Sept 04, 2010; 𝑀𝑤4.6 Nov 06, 2010; 𝑀𝑤4.9 Apr 29, 2011) to build confidence for the 𝑀𝑤 > 7 PP simulations. Thus far, our simulations include multiple rupture scenarios which test the impacts of hypocentre location and the finite-fault stochastic rupture representation of the source itself. In particular, we have identified the need to use location-specific 1D 𝑉𝑠/𝑉𝑝 models for the high frequency part of the simulations to better match observations.

BeckerFraserPhotos October 2011 photograph 001

Images, UC QuakeStudies

Photograph captioned by BeckerFraserPhotos, "Central City skyline".

Sanctioned Graffiti Across the City Photograph 1

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A photograph taken in December 2012 of street art on Westminster Street.

Central City Delivery Plan Presentation - Short Version

Articles, UC QuakeStudies

A shortened version of a presentation created in 2011, outlining the approach to the central city rebuild.

Central City Tour, 4 April 2011 - Photograph 35

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Damaged buildings on Manchester Street, looking south from the intersection with St Asaph Street.

Army personnel secure the cordon in the central city

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Army personnel secure the cordon in the central city.

Photograph by Jennifer Middendorf 355

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Painted lines on the road at the corner of Hereford and Colombo Streets, part of the Christchurch City Council's Transitional City project.

Unsanctioned Graffiti Across the City Photograph 3

Images, UC QuakeStudies

A photograph of graffiti by DEAK on a wall in Cashel Street.

Unsanctioned Graffiti Across the City Photograph 7

Images, UC QuakeStudies

A photograph of graffiti by PWR on a wall in Edgeware Road.

Unsanctioned Graffiti Across the City Photograph 2

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A photograph of graffiti by SULK on a wall in Cashel Street.

Lions roar back into the city centre

Articles, UC QuakeStudies

A web story about the return of the stone lions to the Memorial Arch.

QuakeStory Photo 746

Images, UC QuakeStudies

A photograph submitted by Tim Kerr to the QuakeStories website. The description reads, "Sometimes you had to take a closer look – City pump station out New Brighton way".