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Images for earthquake liquefaction; more images...

Articles, UC QuakeStudies

This report describes the earthquake hazard in Ashburton district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Mt Hutt-Mt Peel Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Articles, UC QuakeStudies

This report describes the earthquake hazard in Selwyn district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Porters Pass-Amberley Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Articles, UC QuakeStudies

This report describes the earthquake hazard in Timaru district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Mt Hutt-Mt Peel Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Images, eqnz.chch.2010

Hargood Street (23.02.2011) Woolston Christchurch Canterbury New Zealand © 2011 Phil Le Cren Photo Taken With: Canon EOS 1000D + Canon EF/EF-S lenses + 10.1 effective megapixels + 2.5-inch TFT color LCD monitor + Eye-level pentamirror SLR + Live View shooting. + EOS Built-in Sensor cleaning system + Wide-area 7 poin...

Images, eqnz.chch.2010

Hargood Street (23.02.2011) Woolston Christchurch Canterbury New Zealand © 2011 Phil Le Cren Photo Taken With: Canon EOS 1000D + Canon EF/EF-S lenses + 10.1 effective megapixels + 2.5-inch TFT color LCD monitor + Eye-level pentamirror SLR + Live View shooting. + EOS Built-in Sensor cleaning system + Wide-area 7 poin...

Images, UC QuakeStudies

A photograph of tents and shipping containers in Hagley Park which were to be part of the Ellerslie International Flower Show. The show was cancelled in the aftermath of the 22 February 2011 earthquake. In the foreground of this photograph, liquefaction can still be seen on the grass.

Images, UC QuakeStudies

The ruins of the historic Durham Street Methodist Church in the aftermath of the 22 February 2011 earthquake. The only parts of the building still upright are those supported by steel braces placed there after the 4 September 2010 earthquake to strengthen the building as it awaited repairs. Rubble has spilled out onto the street, knocking over the safety fences that were also erected after September. Silt from liquefaction has covered the road around the church.

Images, UC QuakeStudies

The ruins of the historic Durham Street Methodist Church in the aftermath of the 22 February 2011 earthquake. The only parts of the building still upright are those supported by steel braces placed there after the 4 September 2010 earthquake to strengthen the building as it awaited repairs. Rubble has spilled out onto the street, knocking over the safety fences that were also erected after September. Silt from liquefaction has covered the road around the church.

Images, UC QuakeStudies

The ruins of the historic Durham Street Methodist Church in the aftermath of the 22 February 2011 earthquake. The only parts of the building still upright are those supported by steel braces placed there after the 4 September 2010 earthquake to strengthen the building as it awaited repairs. Rubble has spilled out onto the street, knocking over the safety fences that were also erected after September. Silt from liquefaction has covered the road around the church.

Research papers, University of Canterbury Library

The paper presents preliminary findings from comprehensive research studies on the liquefaction-induced damage to buildings and infrastructure in Christchurch during the 2010-2011 Canterbury earthquakes. It identifies key factors and mechanisms of damage to road bridges, shallow foundations of CBD buildings and buried pipelines, and highlights the implications of the findings for the seismic analysis and design of these structures.

Research papers, University of Canterbury Library

Earthquake-triggered soil liquefaction caused extensive damage and heavy economic losses in Christchurch during the 2010-2011 Canterbury earthquakes. The most severe manifestations of liquefaction were associated with the presence of natural deposits of clean sands and silty sands of fluvial origin. However, liquefaction resistance of fines-containing sands is commonly inferred from empirical relationships based on clean sands (i.e. sands with less than 5% fines). Hence, existing evaluation methods have poor accuracy when applied to silty sands. Also, existing methods do not quantify appropriately the influence on liquefaction resistance of soil fabric and structure, which are unique to a specific depositional environment. This study looks at the influence of fines content, soil fabric (i.e. arrangement of soil particles) and structure (e.g. layering, segregation) on the undrained cyclic behaviour and liquefaction resistance of fines-containing sandy soils from Christchurch using Direct Simple Shear (DSS) tests on soil specimens reconstituted in the laboratory with the water sedimentation technique. The poster describes experimental procedures and presents early test results on two sands retrieved at two different sites in Christchurch.

Images, UC QuakeStudies

Damage to a house in Richmond. The brick wall is badly cracked and twisted, and some bricks have fallen, exposing the lining paper below. The driveway is cracked and covered in liquefaction. The photographer comments, "These photos show our old house in River Rd. More shaking damage on the east wall of the living room at our house".

Images, UC QuakeStudies

A photograph of the earthquake damage to St Paul's School in Dallington. Large cracks can be seen in the surface of the asphalt. Silt from liquefaction is visible in front of the school buildings. Tape has been placed on the building to keep people away.

Research papers, University of Canterbury Library

Liquefaction-induced lateral spreading in large seismic events often results in pervasive and costly damage to engineering structures and lifelines, making it a critical component of engineering design. However, the complex nature of this phenomenon leads to designing for such a hazard extremely challenging and there is a clear for an improved understanding and predicting liquefaction-induced lateral spreading. The 2010-2011 Canterbury (New Zealand) Earthquakes triggered severe liquefaction-induced lateral spreading along the streams and rivers of the Christchurch region, causing extensive damage to roads, bridges, lifelines, and structures in the vicinity. The unfortunate devastation induced from lateral spreading in these events also rendered the rare opportunity to gain an improved understanding of lateral spreading displacements specific to the Christchurch region. As part of this thesis, the method of ground surveying was employed following the 4 September 2010 Darfield (Mw 7.1) and 22 February 2011 Christchurch (Mw 6.2) earthquakes at 126 locations (19 repeated) throughout Christchurch and surrounding suburbs. The method involved measurements and then summation of crack widths along a specific alignment (transect) running approximately perpendicular to the waterway to indicate typically a maximum lateral displacement at the bank and reduction of the magnitude of displacements with distance from the river. Rigorous data processing and comparisons with alternative measurements of lateral spreading were performed to verify results from field observations and validate the method of ground surveying employed, as well as highlight the complex nature of lateral spreading displacements. The welldocumented field data was scrutinized to gain an understanding of typical magnitudes and distribution patterns (distribution of displacement with distance) of lateral spreading observed in the Christchurch area. Maximum displacements ranging from less than 10 cm to over 3.5 m were encountered at the sites surveyed and the area affected by spreading ranged from less than 20 m to over 200 m from the river. Despite the highly non-uniform displacements, four characteristic distribution patterns including large, distributed ground displacements, block-type movements, large and localized ground displacements, and areas of little to no displacements were identified. Available geotechnical, seismic, and topographic data were collated at the ground surveying sites for subsequent analysis of field measurements. Two widely-used empirical models (Zhang et al. (2004), Youd et al. (2002)) were scrutinized and applied to locations in the vicinity of field measurements for comparison with model predictions. The results indicated generally poor correlation (outside a factor of two) with empirical predictions at most locations and further validated the need for an improved, analysis- based method of predicting lateral displacements that considers the many factors involved on a site-specific basis. In addition, the development of appropriate model input parameters for the Youd et al. (2002) model led to a site-specific correlation of soil behavior type index, Ic, and fines content, FC, for sites along the Avon River in Christchurch that matched up well with existing Ic – FC relationships commonly used in current practice. Lastly, a rigorous analysis was performed for 25 selected locations of ground surveying measurements along the Avon River where ground slope conditions are mild (-1 to 2%) and channel heights range from about 2 – 4.5 m. The field data was divided into categories based on the observed distribution pattern of ground displacements including: large and distributed, moderate and distributed, small to negligible, and large and localized. A systematic approach was applied to determine potential critical layers contributing to the observed displacement patterns which led to the development of characteristic profiles for each category considered. The results of these analyses outline an alternative approach to the evaluation of lateral spreading in which a detailed geotechnical analysis is used to identify the potential for large spreading displacements and likely spatial distribution patterns of spreading. Key factors affecting the observed magnitude and distribution of spreading included the thickness of the critical layer, relative density, soil type and layer continuity. It was found that the large and distributed ground displacements were associated with a thick (1.5 – 2.5 m) deposit of loose, fine to silty sand (qc1 ~4-7 MPa, Ic 1.9-2.1, qc1n_cs ~50-70) that was continuous along the bank and with distance from the river. In contrast, small to negligible displacements were characterized by an absence of or relatively thin (< 1 m), discontinuous critical layer. Characteristic features of the moderate and distributed displacements were found to be somewhere between these two extremes. The localized and large displacements showed a characteristic critical layer similar to that observed in the large and distributed sites but that was not continuous and hence leading to the localized zone of displacement. The findings presented in this thesis illustrate the highly complex nature of lateral displacements that cannot be captured in simplified models but require a robust geotechnical analysis similar to that performed for this research.