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40 Glossary This glossary presents definitions for common terms and abbreviations used throughout this synthesis. Accelerometers A type of instrument that measures acceleration forces in multiple dimensions and can be indicative of movement. Aerial LiDAR A remote-sensing method that uses light in the form of a pulsed laser mounted to an aircraft to create a 3D model of the Earthâs surface and structures. Aerial photogrammetry A remote-sensing method that involves the processing of multiple aerial photographs to create a 3D model of the Earthâs surface and structures. Borehole extensometer/ Devices installed in a borehole with two points of refer- deformation system ence. As a slope deforms, these two points of reference will move with respect to each other, allowing for the quanti- fication of extension or compression in the borehole. Data management Systems and tools that may be used for acquisition, storage, transmission, analysis, presentation, and visualization. Event video or photo Cameras installed specifically for monitoring slope capture systems movement by recording footage of movement occurring, allowing for direct co-location of where the slope move- ment occurred. Event warning systems to agency Instrumentation and monitoring systems that are designed staff (e.g., operations, engineering) to provide early warning to operational staff. Event warning systems to public Instrumentation and monitoring systems that are designed or external stakeholders to provide early warning to the public/external stakeholders. Geotechnical instrumentation Includes physical instrumentation devices or equipment and monitoring technologies installed on or in unstable slopes, remote sensing from either ground-, aerial-, or satellite-based platforms; warn- ing systems that detect and/or communicate movement of unstable slopes. Global positioning system (GPS) A satellite-based radio navigation system that provides geolocation and time information to a GPS receiver any- where on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. GPS can be used
Glossary 41 to monitor unstable slopes through the characterization of the movement of discrete points within the landslide through time. Ground-based LiDAR A remote-sensing method that uses light in the form of a pulsed laser to create a 3D model of the Earthâs surface and structures. Ground-based photogrammetry A remote-sensing method that involves the processing of multiple photographs to create a 3D model of the Earthâs surface and structures. Ground-based radar Use of radar methods to generate 3D models of a slope and the deformation if multiple measurements are taken over time. Ground-based survey A method that measures points along the slope using conventional survey techniques to construct 3D models and terrain maps. Groundwater levels or flow Measurement of changes in groundwater levels to deter- mine elevation and gradient of flow. Inclinometer systems Also known as IPI probes, in-place inclinometer systems (In-place systems) are placed at discrete locations along a casing. In-place systems differ from traversing probe systems in that they remain in the ground and can offer near-real-time deformation measurement. Inclinometer systems A traversing probe inclinometer is an instrument placed (Traversing probe systems) into a casing pipe to measure pipe inclination at defined intervals in the subsurface, creating a profile of ground deformation within the measurement interval. Instrumentation Devices that are placed on or in the ground and used for measuring and recording physical properties such as moisture, temperature, deformation, inclination, or pressure. Monitoring The use of multiple observations or data collection events for an unstable slope. Monitoring can be a short-duration activity that involves only a few observations or param- eters or involve long-term programs that span years or decades and include multiple forms of data collection. Real-time video streams Onsite cameras that record footage of slope movement occurring allowing for direct co-location of where the slope movement occurred. Often this can take the form of traffic cameras along a highway. Remote sensing A monitoring technique that acquires data about an unstable slope or other feature from a distance that can range from a nearby ground-based location, aerial plat- forms, and satellites. Remote-sensing technologies rely on the scanning and analysis of reflected energy and/or visible and multi-spectral imaging of the ground surface or a structure.
42 Advances in Unstable Slope Instrumentation and Monitoring Satellite InSAR A remote-sensing technique using interferometric synthetic aperture radar to generate maps of geomorphology and/or surface deformation of a large area with the potential to read small differential movements. Significant event A hazard event that results in substantial damage to DOT assets and/or other property, several days or weeks of mobility disruption, and/or adverse safety consequences. Significant event detection Instrumentation that detects when a hazard event that systems results in substantial damage to DOT assets and/or other property has occurred. Strain gauges Devices that are placed on an object that allow for measure- ments of strain that could be a result of slope movement. Surface extensometer/ Devices that measure the lateral displacement of a location deformation system on the surface of an unstable slope. Depending on the method used, the systems allow for the quantification of both displacement rate and displacement direction. Tilt measurement An instrument used to quantify the deflection of a discrete slope surface by measuring inclination angle of the surface at a given time. Unmanned aerial vehicle An aircraft with no pilot on board. UAVs can be remote (UAV) controlled or can fly autonomously based on pre- programmed flight plans. UAVs can be used in conjunc- tion with aerial remote-sensing techniques. Unstable slopes Embankments, cut slopes, and beyond-the-right-of-way slope hazard sites that have exhibited movement or present a threat of movement.
