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Centre for Integrated Petroleum Research University of Bergen & Unifob, Norway Walter Wheeler & Simon Buckley Unifob, UiB Bergen, Norway Lidar laser scanning.

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Presentation on theme: "Centre for Integrated Petroleum Research University of Bergen & Unifob, Norway Walter Wheeler & Simon Buckley Unifob, UiB Bergen, Norway Lidar laser scanning."— Presentation transcript:

1 Centre for Integrated Petroleum Research University of Bergen & Unifob, Norway Walter Wheeler & Simon Buckley Unifob, UiB Bergen, Norway Lidar laser scanning & photogrammetry for: Paleoseismology Culturally-important structures Local deformation studies Local deformation studies Hazard assessment

2 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Introduction Digital survey techniques have become important in earth sciences, due to technological advances in: GPS Digital photogrammetry Remote sensing Terrestrial and Aerial laser scanning (Lidar). Data allows high spatial resolution, accuracy, automation and ease of use. Representation of buildings and landforms in digital form, full 3D GIS, allowing further interpretation. New ‘products’ can be developed, Virtual geology (virtual 3D trenches) Dense-data-coverage geodesy (repeat surveys at deformation sites) Hazard assessment (slide hazards) Documenting culturally-important sites and buildings (restoration).

3 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Lidar Overview Rapid means of acquiring 3D point data Eye-safe laser Measures four components: Hz angle, v angle, distance strength of laser return (intensity) Converts to x, y, z coordinates 360° field of view, 800 m range quoted point accuracy of 5 mm laptop interface GPS reference frame Digital camera mounted on scanner head provides colour and texture calibrated in lab conditions Multiple scans used to for larger coverage and to avoid shadows

4 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Final Product: Virtual Outcrop DEM textured with photographic images (Lorca, Spain). Model size can be meters to kilometers What can be done with the data? Accurately measure and interpret in 3D Map areas otherwise not accessible Repeat observations

5 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB USES Methods Ground-based lidar: good for local surveys and steep surfaces. Airborne lidar: typically broad coverage of landforms. Products Laser-ranging DEM textured with photographs and other data Point-cloud with cm accuracy and data coverage Maximum range about 800 m; 1.6 km covered from one point. Virtual-reality immersion environment (interpretation, discussion) Applications Paleoseismology (a “virtual trench”) Documenting historical buildings Repeat deformation studies in a km-sized area (InSAR-like) DEM for landform analysis to determine slide / avalanch / flooding paths.

6 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Lidar in Paleoseismology / trenching Trench Interpretations 1. Create a virtual model of a trench to sub-cm resolution. 2. Add field interpretations in the field. 3. Widen the trench and re-scan, developing a true 3D model of paleoseismic features. 4. Later (in lab or at conference) : discuss and refine interpretations in virtual reality environment. Cliff exposures  Enable cm-scale interpretation and measurements of inaccessible areas

7 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Lidar possibilities in deformation studies Co-seismic strain ? Inter-seismic strain / creep? Local, high-resolution 3D strain models Rapidly cover several sq. Kilometers (per day) Sub-cm accuracy and repeatability Local, regional and GPS reference frames Reduce dependence on monument integrity Augment more accurate (more limited) survey methods Repeat surveys  Not just “another InSAR” but  3D definition of strain field.  All objects become “monuments”.

8 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Lidar applications in natural hazards Local DEM and detailed landform analysis Slide, avalanche and flood pathways Mapping of paleo slide-deposits Slope steepness and relation to joints & bedding Airborne lidar typically more effective than ground based where area to be covered is typically large. Ground-based or helicopter lidar may be necessary for paleo-seismology aspects and cliff-side evaluation. Can be integrated with satellite & airborne remote sensing data. Spectral data can be used to quantify active erosion and transportation pathways (exposed soil / regolith / lack of vegetation).

9 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Brodick Castle, 1 cm resolution, 2 days (Archæopterix Ltd.). Document culturally important sites... Lidar scan -> 3D point-cloud model -> CAD generation of elevation drawings, sections and plans. Sphinx Triangulated point cloud from 6 scan positions Reigel laser measurement systems (www.reigel.com)

10 ARAMIS lidar / virtual outcrop - virtual trench W.Wheeler May-15 UNIFOB - UiB Conclusions Lidar is a fast means of acquiring cm- to sub-cm spatial data to assist with geological modelling. Data accuracy is higher than previously achievable. Workflow developed for creating and using virtual outcrops, and viewing in virtual-rality environments. Applications in several areas of EQ hazard assessment & paleoseismology.


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