Guy Aubé¹, Vern Singhroy², Corey Froese³ and Paul Briand¹
¹ Canadian Space Agency, Earth Observation Applications and Utilizations, 6767 route de l’Aéroport, St-Hubert, Québec, Canada, J3Y 8Y9
² Natural Resources Canada, Canada Centre for Remote Sensing, 580 Booth, Ottawa, Ontario, Canada, K1A 0E8
³ Alberta Geological Survey/Energy Resources Conservation Board, 4999, 98 Ave., Edmonton, Alberta, Canada, T6B 2X3
Over the last decade, the Canadian Space Agency (CSA) has been involved in the support of scientific initiatives, demonstration projects and operational implementation activities related to disasters and security management. Through the Government Related Initiatives Program (GRIP), the CSA and its public and private sector partners have fostered the development of Earth Observation (EO) information and services related to geohazards. This article discusses the critical role the CSA applications development programs, projects and assets (space and ground segments) can play in ensuring the integration of EO in the management and stewardship of this sensitive area, and a greater awareness and appreciation by Canadians of the benefits that they receive from the use of EO information, services and products. It also highlights the success of the CSA and its partners from Natural Resources Canada and the Alberta Geological Survey, which developed new InSAR methods and techniques. These techniques demonstrate the potential of RADARSAT-1 and 2 to improve the assessment and mitigation of geohazards, such as ground subsidence and landslides, in Canada. This initiative is directly linked with the Global Earth Observation System of Systems (GEOSS) 10-Years Implementation Plan (section 4.1.1. Disasters: loss of life and property from natural and human-induced disasters) and contributes to the GEO 2007-2009 Work Plan (i.e. DI-06-03: Integration of InSAR Technology).
Disasters: Action is Needed Now to Ensure Our Quality of Life
The Canadian Space Agency (CSA) understands the tremendous role and value that space-based Earth Observation (EO) systems and information have regarding disaster management, mitigation, response and its environmental and socio-economic impacts and benefits. Security, which includes disaster and geohazard management, is one of the three pillars of the CSA EO strategy. Our vision is for Canada to be an internationally recognized leader in the development and use of EO applications in support of national priorities. We recognize that threats to our environment are a clear danger in the context of climate change and we believe that action is needed now to ensure our quality of life, particularly for those most vulnerable to health threats from environmental and technological disasters. The security area is not only defined by disaster management, but by a wide variety of events that could affect the environment and health of the population.
|Figure 1. Landslide and soil instability in Alberta Canada.|
Not being prepared is costly. In the past, Canada has experienced multiple catastrophic events (i.e. Spanish flu pandemic, Tseax river cone eruption, Saint-Jean-Vianney mudslide, Red River floods, Okanagan valley fires, Ocean Ranger oil platform sinking, etc.). In 1998, the ice storm in Quebec cost the country $1.2 billion and the droughts of the last decade in our prairies cost Canada’s economy over $3 billion. We now can add glacier and permafrost melting in the Canadian Arctic to the list of hazards which are expected to have a negative impact on our environment and economy. Our need for EO applications to predict severe environmental and man-made disasters has never been greater.
As technologies mature, they yield more benefits and applications. Canada’s government understands how crucial science, technologies and their applications are to building a strong economy. What EO programs do we have in place that will increase socio-economic benefits from disasters management through EO applications? What are the space and ground assets that we have to improve the assessment and mitigation of geohazard in Canada? How do we assess and mitigate active geohazard sites in Canada from space? This article highlights the CSA EO programs, projects and assets (ground and space segments) related to geohazard management that answer these questions. It also gives an example of one of the Canadian EO success stories in geohazard monitoring using InSAR technologies.
This initiative is directly linked with the Global Earth Observation System of System (GEOSS) 10-Years Implementation Plan (section 4.1.1. Disasters: loss of life and property from natural and human-induced disasters) and contributes to the GEO 2007-2009 Work Plans (i.e. DI-06-03: Integration of InSAR Technology). It also supports Canadian government priorities to secure our energy future, preserve Canada’s environment, keep Canadians safe, contribute to global security and build stronger institutions.
Earth Observation Programs
Canada is among the world leaders in EO applications and utilizations. Since 2000, the CSA EO Applications and Utilization Division (EOAU) has managed over 200 projects and distributed over $45M in funding through its EO programs to Canadian government organisations, industry and universities.
Government Related Initiatives Program (GRIP)
|Figure 2. CSA EO GRIP program supports the development and demonstration of new EO
applications that increase the benefits and effectiveness of the Government services for
The GRIP focuses on developing government use of space-based land, ocean, and atmospheric observation systems and services. It supports the development and demonstration of new applications that increase the benefits and effectiveness of GoC services for Canadians through use of EO information sources, and raises awareness within the GoC of the uses and benefits of Canadian supported EO missions. In the last few years, GRIP has supported the development of geohazard related projects with Canadian departments such as Natural Resources Canada (NRCAN) and Defence Research and Development Canada (i.e. InSAR monitoring of active geohazards sites in Canada; operational delivery of predictive regional geological mapping products in EO; critical infrastructure monitoring for the energy sector).
Earth Observation Application Development Program (EOADP)
The EOADP aims to promote the development of applications within the industry that will maximize the utilization of EO satellite data generated by CSA-supported missions. Its strength partnerships with Canadian industry are well suited to capitalize on space-based EO technologies to develop innovative products and services. Since the early 2000s, EOADP has supported the development of geohazard related projects with the industry: Frank Slide InSAR Monitoring (Atlantis); geological and environmental mapping for the oil and gas industry (IIT); development of an InSAR ÛÒ calibrated mine induced subsidence/deformation safety model (MDA); integrated pipeline geohazard monitoring service (MDA-GSI); oil field land deformation surveying with integrated InSAR (MDA); Application of RADARSAT-1 to the exploration for natural gas in Adirondack (MIR); cost-effective geologic mapping and mineral deposit targeting algorithms (PGW); integration pipeline geohazard monitoring service (RSI); measurement of horizontal and vertical motion using InSAR (TRE Canada); New Orleans subsidence monitoring (USGS); monitoring subsidence in urban areas (Vexcel).
The SOAR program for RADARSAT-2 is a joint partnership program between MacDonald Dettwiler and Associates Ltd. – Geospatial Services Inc. and the Canadian government through the CSA and NRCAN Canada Centre for Remote Sensing (CCRS). The program provides access to RADARSAT-2 data for research and testing purposes. Since 2006, SOAR has supported the development of geohazard related projects with the science and academic EO community: InSAR monitoring of landslides along transportation routes (CCRS); monitoring of mining induced surface deformation (Gamma RS); application of new DInSAR techniques using RADARSAT-2 data (ICC); ICA techniques applied to SAR interferometry (MARSec); evaluation of RADARSAT2 to monitor landslides in Brazil (UNEP); investigation of volcanic hazards with RADARSAT-2 (U. of Manitoba); ground movement monitoring in Australia using Radarsat-2 (U. of South Wales).
Earth Observation Assets
Canadian Radar EO satellites, RADARSAT 1/2, are key resources in a variety of disaster management scenarios. RADARSAT data has been used effectively in disaster responses such as earthquakes, tsunamis, floods, landslides, forest fires, and other natural or technological disasters. The ability to deliver data in near-real time is essential for relief operations to map and monitor damage, and for assessing the impact on the future. RADARSAT images support activities related to the operational mapping and monitoring of natural disasters, such as:
Û¢ Prevention that involves gathering baseline data, identifying potential hazardous sites and assessing the availability of facilities and equipment necessary to assist in emergency response activities;
Û¢ Preparedness that involves monitoring the high-risk area in order to provide early warning of potential disasters;
Û¢ Emergency response to a specific incident that involves identification of the location, assessment of the extent of the disaster and short-term monitoring of the event;
Û¢ Recovery by monitoring the affected areas for damage assessment and environmental impact to aid the reconstruction and rehabilitation of an area.
For satellite imagery to be effective during disasters, three basic criteria must be met: (1) satellite sensors must be able to detect the phenomenon and subsequent changes; (2) satellites must have reliable and frequent coverage over the area affected; (3) satellite data must be delivered to the end-user in a timely fashion.
|Figure 3. The RADARSAT Constellation mission is being
designed for three main uses: maritime surveillance; disaster
management; and ecosystem monitoring. (CSA, 2008)
RADARSAT-1 is a sophisticated EO satellite developed by Canada to monitor environmental changes and the planet’s natural resources. It provides Canada and the world with an operational radar satellite system capable of timely delivery of large amounts of data in all weather and through cloud cover, smoke and haze.
RADARSAT-2 is Canada’s next-generation commercial radar satellite, and offers powerful technical advancements that enhance marine surveillance, ice monitoring, disaster management, environmental monitoring, resource management and mapping in Canada and around the world. RADARSAT-2 reduces planning lead times for data acquisition, and its left- and right-looking modes provide more revisits and up-to-date data.
The RADARSAT Constellation is the evolution of the RADARSAT program with the objective of ensuring C-band data continuity, improved operational use and improved system reliability over the next decade. The baseline mission includes three satellites, but the constellation is designed to be scalable to six satellites. The three-satellite configuration will provide complete coverage of Canada’s land and oceans offering an average daily revisit at 50m resolution. It will also offer average daily access to 95 percent of the world. The satellite design and development activities are beginning now, with satellite launches planned for 2012, 2013 and 2014. The Constellation mission is being designed for three main uses: maritime surveillance; disaster management; and ecosystem monitoring. Its rapid image revisits over the same location will improve our emergency management during all disasters phases (mitigation, warning, response, recovery).
Through the co-operation agreement between the government of Canada and the European Space Agency (ESA), Canada chose to participate in the ENVISAT environmental satellite program. ENVISAT will complement R1 and assure data continuity between R1 and R2.
Data collected by R1 is transmitted directly to a data reception facility. The receiving stations provide: complete and reliable real-time coverage around the world; consistency in format for high-quality products; and timely delivery of the requested data. The R1 network now comprises 33 data reception facilities. R2 ground segment systems are housed in CSA facilities in Longueuil, Quebec, and Saskatoon, Saskatchewan, in CCRS facilities in Gatineau, Quebec, and Prince Albert, Saskatchewan, and MDA headquarters in Richmond, British Columbia. This extensive network also includes reception, archiving, and processing capacity in facilities all over the world.
Monitoring Initiative for Active Geohazard Sites in Canada
Since 2005, the CSA, through the GRIP Program, has worked with the CCRS on a project involving the application of InSAR technology to map and characterize ground hazards in Western Canada. The project involves characterizing subsidence over abandoned coal mine workings, movements along active faults and slope movement for landslides in the Rocky Mountains, Alberta Plains and in Canada’s arctic. All sites chosen for this study are located along strategic transportation and energy corridors. This project is not only meant to demonstrate the application of InSAR monitoring along Canada strategic energy and transportation corridors but also to build InSAR monitoring capacity within NRCAN’s Earth sciences sector and the Alberta Geological Survey.
InSAR deformation monitoring as a routine hazard assessment method is in its early stage of development in Canada. There is a need to develop convincing case studies at difficult high-risk sites that will be used to establish an InSAR monitoring baseline for continuous integrated monitoring along Canada’s strategic transportation and energy corridors. The project objectives are: (1) to produce InSAR products of active landslide areas along strategic transportation and energy corridors, and of selective seismically active areas in Canada; (2) produce an InSAR image archive of selected active geohazard areas in Canada.
The areas selected for this investigation include: large and small active vegetated landslides along strategic energy and transportation corridors (Trans Canada Highway in the Rockies, Mackenzie Valley Pipeline, the Town of Peace River/Highway 2 Corridor, and Highway 49 Crossing of the Little Smoky Highway River, Alberta); and the seismically active Leach River fault affecting the city of Victoria.
Multi-temporal InSAR maps have provided an input for modeling the seasonal motion behaviour and predictability of these hazard sites in order to develop the mitigation strategies for these high-risk areas. As some of these geohazard sites are vegetated and wet, which results in non coherent targets, the installation of corner reflectors as coherent targets is a significant part of this integrated InSAR monitoring development strategy.
The results of the project are: the successful integration of field-installed corner reflector technology and InSAR analysis to monitor gradual motion at high risk geohazard sites. The published results involved the collective efforts of our provincial and Geological Survey of Canada partners (Singhroy et al, 2007, 2008, Singhroy 2008 Froese et al 2008, Mei et al 2007). The examples below provide three samples of InSAR monitoring in Alberta.
Crowsnest Pass/Highway 3, Alberta
The Crowsnest Pass in Southwestern Alberta is an important trade corridor. Both provincial Highway 3 and CP Rail transport people and goods. Much of the settlement in the corridor occurred in the early 1900s when coal mining in the region led to many decades of mining of underground coal seams in the area. Perhaps the most memorable event from this time period was the 1903 Frank Slide, Canada’s deadliest landslide which killed over 80 people when it buried a portion of the mining town of Frank. The legacy of the coal mining rush in the region is a series of abandoned underground coal mines that underlay modern-day infrastructure and urban development.
Highway 49/Little Smoky River Crossing, Alberta
The Little Smoky River bridge and approach roads were completed in 1957. Since that time there has been ongoing valley slope instability that has impacted the highway and west bridge abutment, resulting in ongoing costly maintenance issues. As the repairs to the highway, a major trade route for north western Alberta, cost the Alberta government many hundreds of thousands of dollars per year, studies are underway to provide a viable long-term solution to mitigate the impacts of this slope movement on the highway. Options were considered for stabilization of the slide, and for highway realignment away from the area of greatest instability. All options are costly and limited information is available to confirm the viability of each option due to the very deep slide plane. As there are significant decisions to be made by Alberta Transportation (AT) with very little data on the valley walls, the use of InSAR with corner reflectors was considered to be an exciting option for acquiring a wide array of data.
|Figure 6. Photo of a corner reflector installed at the Little
In October 2006, an array of eighteen small areas was cleared of vegetation and corner reflectors were installed by personnel from AGS, AT, CCRS and the University of Alberta. Each reflector, in the shape of a four-sided pyramid, was aimed so that the large open end was oriented to be directly perpendicular to the direction of radar pulses emitted from the orbiting Radarsat-1 satellite, which obtains results over the site every 24 days. The reflectors are used to provide an amplified signal back to the satellite, when compared to the heavily vegetated surrounding areas. As of November 2008, a set of 28 readings was obtained for each reflector and the results processed at the CCRS offices in Ottawa. The processed results have been taken by AGS Geological Hazards staff and compared against conventional geotechnical instrumentation on the site (slope inclinometers) and visual interpretations of the complex slope movements on the site. A set of GPS readings was also taken by AGS, AT and CCRS staff during the summer of 2008. Final results are being currently reviewed by CCRS and AGS.
Highway 2 Corridor/Town of Peace River, Alberta
The Town of Peace River is located along the floodplain and valley walls of the Peace River in north western Alberta. Although aesthetically pleasing, a large portion of its urban footprint and transportation infrastructure is built either on the flood plain or on the unstable valley walls of the Peace River Valley. Beginning in 2006, a study was initiated to characterize the extent, rates and style of the large scale landslides in and around the municipality and assess their impacts on the highways, gas transmission and distribution pipeline networks, and urban infrastructure. As the glacial history is complex and landslides originate in various settings, the initial components of the study are the development of a three dimensional geological model and completion of an inventory of documented landslides in order to determine logical groupings for landslide types.
|Figure 7. A bare earth LiDAR image showing the large
landslides on which the town of Peace River and Highway 2
In order to develop an understanding of the historical movement rates and extents, an InSAR study will review deformation trends between 1992 and 2006 and compare these results to deformations recorded using conventional instrumentation over this time period. This work is currently underway and involves collaboration between AGS, CCRS and the University of TromsÌü (Norway). It is expected that the results of the InSAR will be a key component of the hazard analysis and aid in decision making as to mitigation and future land use planning.
It is clear from these examples and the published results, RADARSAT InSAR monitoring of selected high risk landslide sites affecting transportation routes is providing convincing case studies and guidelines for other users to apply. Over the duration of the InSAR Canadian Space Agency GRIP project, the Alberta Geological Survey and Natural Resource Canada have increased their uses of InSAR techniques, which are now becoming routine in monitoring high ÛÒ risk sites. A large archive of InSAR data for these sites is now available, and will be used for future long term integrated monitoring of these unstable slopes that are affecting our transportation routes.
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