The Ottawa/Gatineau region has significant deposits of sensitive glacial marine clay. As these deposits have risen due to isostatic rebound, these materials have been incised by various watercourses, carving river valleys throughout the region. The slopes of these river banks are susceptible to retrogressive slides with significant travel distances. A novel method of monitoring changes in these landslides has been developed and is explained in this thesis. Using a tethered blimp as an aerial photo platform, high resolution digital elevations models (DEM) with accuracies of ±0.49m on vegetated slopes have been created using photogrammetry. These DEMs have been created for a several photos sets taken over time. This allows changes over time to be monitored. The use of ground control points (GCP) allows for the complete three dimensional movement of discrete points to be monitored over time. The photogrammetric DEM have been compared to similar DEM derived from LiDAR surveying. By complimenting these surveys with historical aerial photos it is possible to develop better models of landslide failure processes, which will ultimately provide better predictions of movements and failure. When movements and failures can accurately be predicted it will then be possible to better manage the risk associated with these landslides events. / Thesis (Master, Civil Engineering) -- Queen's University, 2012-01-30 16:20:27.13

No description available.

Disasters can occur without warning and severely test society’s capacity to cope, significantly altering the relationship between society and the built and natural environments. The scale of a disaster is a direct function of the pre-event actions and decisions taken by society. Poor pre-event planning is a major contributor to disaster, while effective pre-event planning can substantially reduce, and perhaps even avoid, the disaster. Developing and undertaking effective planning is therefore a vital component of disaster risk management in order to achieve meaningful societal resilience. Disaster scenarios present arguably the best and most effective basis to plan an effective emergency response to future disasters. For effective emergency response planning, disaster scenarios must be as realistic as possible. Yet for disasters resulting from natural hazards, intricately linked secondary hazards and effects make development of realistic scenarios difficult. This is specially true for large earthquakes in mountainous terrain. The primary aim of this thesis is therefore to establish a detailed and realistic disaster scenario for a Mw8.0 earthquake on the plate boundary Alpine fault in the South Island of New Zealand with specific emphasis on secondary effects. Geologic evidence of re-historic earthquakes on this fault suggest widespread and large-scale landsliding has resulted throughout the Southern Alps, yet, currently, no attempts to quantitatively model this landsliding have been undertaken. This thesis therefore provides a first attempt at quantitative assessments of the likely scale and impacts of landsliding from a future Mw8.0 Alpine fault earthquake. Modelling coseismic landsliding in regions lacking historic inventories and geotechnical data (e.g. New Zealand) is challenging. The regional factors that control the spatial distribution of landsliding however, are shown herein to be similar across different environments. Observations from the 1994 Northridge, 1999 Chi-Chi, and 2008 Wenchuan earthquakes identified MM intensity, slope angle and position, and distance from active faults and streams as factors controlling the spatial distribution of landsliding. Using fuzzy logic in GIS, these factors are able to successfully model the spatial distribution of coseismic landsliding from both the 2003 and 2009 Fiordland earthquakes in New Zealand. This method can therefore be applied to estimate the scale of landsliding from scenario earthquakes such as an Alpine fault event. Applied to an Mw8.0 Alpine fault earthquake, this suggests that coseismic landsliding could affect an area >50,000 km2 with likely between 40,000 and 110,000 landslides occurring. Between 1,400 and 4,000 of these are expected to present a major hazard. The environmental impacts from this landsliding would be severe, particularly in west-draining river catchments, and sediment supply to rivers in some catchments may exceed 50 years of background rates. Up to 2 km3 of total landslide debris is expected, and this will have serious and long-term consequences. Fluvial remobilisation of this material could result in average aggradation depths on active alluvial fans and floodplains of 1 m, with maximum depths substantially larger. This is of particular concern to the agriculture industry, which relies on the fertile soils on many of the active alluvial fans affected. This thesis also investigated the potential impacts from such landsliding on critical infrastructure. The State Highway and electrical transmission networks are shown to be particularly exposed. Up to 2,000 wooden pole and 30 steel pylon supports for the transmission network are highly exposed, resulting in >23,000 people in the West Coast region being exposed to power loss. At least 240 km of road also has high exposure, primarily on SH6 between Hokitika and Haast, and on Arthur’s and Lewis Passes. More than 2,750 local residents in Westland District are exposed to isolation by road as a result. The Grey River valley region is identified as the most critical section of the State Highway network and pre-event mitigation is strongly recommended to ensure the road and bridges here can withstand strong shaking and liquefaction hazards. If this section of the network can remain functional post-earthquake, the emergency response could be based out of Wellington using Nelson as a forward operating base with direct road access to some of the worst-affected locations. However, loss of functionality of this section of road will result in >24,000 people becoming isolated across almost the entire West Coast region. This thesis demonstrates the importance and potential value of pre-event emergency response planning, both for the South Island community for an Alpine fault earthquake, and globally for all such hazards. The case study presented demonstrates that realistic estimates of potential coseismic landsliding and its impacts are possible, and the methods developed herein can be applied to other large mountainous earthquakes. A model for developing disaster scenarios in collaboration with a wide range of societal groups is presented and shown to be an effective method for emergency response planning, and is applicable to any hazard and location globally. This thesis is therefore a significant contribution towards understanding mountainous earthquake hazards and emergency response planning.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第13300号 / 論理博第1563号 / 新制||理||1653(附属図書館) / (主査)准教授 王 功輝, 教授 釜井 俊孝, 教授 福田 洋一 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM

No description available.

Following the 22 February 2011, MW 6.2 earthquake located on a fault beneath the Port Hills of Christchurch, fissuring of up to several hundred metres in length was observed in the loess and loess-colluvium of foot-slope positions in north-facing valleys of the Port Hills. The fissuring was observed in all major valleys, occurred at similar low altitudes, showing a contour-parallel orientation and often accompanied by both lateral compression/extension features and spring formation in the valley floor below. Fissuring locations studied in depth included Bowenvale Valley, Hillsborough Valley, Huntlywood Terrace–Lucas Lane, Bridle Path Road, and Maffeys Road–La Costa Lane. Investigations into loess soil, its properties and mannerisms, as well as international examples of its failure were undertaken, including study of the Loess Plateau of China, the Teton Dam, and palaeo-fissuring on Banks Peninsula. These investigations lead to the conclusion that loess has the propensity to fail, often due to the infiltration of water, the presence of which can lead to its instantaneous disaggregation. Literature study and laboratory analysis of Port Hills loess concluded that is has the ability to be stable in steep, sub-vertical escarpments, and often has a sub-vertically jointed internal structure and has a peak shear strength when dry. Values for cohesion, c (kPa) and the internal friction angle, ϕ (degrees) of Port Hills loess were established. The c values for the 40 Rapaki Road, 3 Glenview Terrace loess samples were 13.4 kPa and 19.7 kPa, respectively. The corresponding ϕ values were thought unusually high, at 42.0° and 43.4°.The analysed loess behaved very plastically, with little or no peak strength visible in the plots as the test went almost directly to residual strength. A geophysics resistivity survey showed an area of low resistivity which likely corresponds to a zone of saturated clayey loess/loess colluvium, indicating a high water table in the area. This is consistent with the appearances of local springs which are located towards the northern end of each distinct section of fissure trace and chemical analysis shows that they are sourced from the Port Hills volcanics. Port Hills fissuring may be sub-divided into three categories, Category A, Category B, and Category C, each characterised by distinctive features of the fissures. Category A includes fissures which display evidence of, spring formation, tunnel-gullying, and lateral spreading-like behaviour or quasi-toppling. These fissures are several metres down-slope of the loess-bedrock interface, and are in valleys containing a loess-colluvium fill. Category B fissures are in wider valleys than those in Category A, and the valleys contain estuarine silty sediments which liquefied during the earthquake. Category C fissures occurred at higher elevations than the fissures in the preceding categories, being almost coincident with bedrock outcropping. It is believed that the mechanism responsible for causing the fissuring is a complex combination of three mechanisms: the trampoline effect, bedrock fracturing, and lateral spreading. These three mechanisms can be applied in varying degrees to each of the fissuring sites in categories A, B, and C, in order to provide explanation for the observations made at each. Toppling failure can describe the soil movement as a consequence of the a three causative mechanisms, and provides insight into the movement of the loess. Intra-loess water coursing and tunnel gullying is thought to have encouraged and exacerbated the fissuring, while not being the driving force per se. Incipient landsliding is considered to be the least likely of the possible fissuring interpretations.