1. Finding faults with LIDAR in the Puget Lowland Ralph Haugerud, Craig Weaver U. S. Geological Survey Jerry Harless Puget Sound Regional Council and thanks to TerraPoint LLC, Houston TX

2. Why LIDAR? What is LIDAR? How are we doing LIDAR? What are we finding?

3. 30 km In some places, it is easy to see where the active faults are.

4. In other places, it is not. 30 km Seattle Tacoma

5. What are the salient differences? SF Bay area Puget Lowland slip rate 3 cm/yr strike slip 4 mm/yr shortening average tree height ? 10 ft? 100 ft age of landscape ~10 6 years 18,000 years

6. 18,000 yr  1 mm/yr = 18 m 10 6 yr  1 mm/yr = 1 km In the Puget Lowland, to see a fault with the same slip rate as in the SF Bay area, we have to look more closely. age  slip rate = feature size

7. LI ght D etection A nd R anging Airborne scanning laser rangefinder Differential GPS Inertial Navigation System 30,000 points per second at ~15 cm accuracy $400–$1000/mi 2, 10 6 points/mi 2, or 0.04–0.1 cents/point Extensive filtering to remove tree canopy (virtual defor- estation)

9. 10-meter DEM from contours

10. 12-ft DEM from LIDAR

11. Picture: Oblique view of S end Rockaway Beach

12. High-resolution LIDAR topography

13. Fly in winter, when leaves are off Near-infrared laser; doesn’t penetrate clouds, rain Errors Largest are in angles—up to 1 m x-y error Ranging error = ~15 cm z error! 2/3 of surveyed points on trees and buildings; remove with automatic geometric filtering Multiple reflections from one laser pulse = better filtering

14. Optimum working distance circa 1 km –Adequate reflection brightness –Keep laser eye-safe Spot diameter: decimeters to meters Spot spacing: 1 to 5 meters Multiple passes –multiple look angles –higher point density –internal consistency check $400 - $1,000 / mi 2

15. Why is LIDAR better than photogrammetry? (It’s the trees) Suppose timber allows 1 of 3 arbitrary rays to reach ground; 1/3 of ground can be surveyed by LIDAR Photogrammetry requires 2 separate views of a point; only 1/9 of ground will be locatable

16. Bainbridge Island, KPUD 1996-1997 Snoqualmie, USGS-NMD 1998-2001? Seattle Tacoma

17. Puget Sound LIDAR Consortium ParticipantsExpertise Kitsap County Kitsap PUD City of Seattle Puget Sound Regional Council NASA USGS (exclusive of USGS) –Contracting –Surveyor –prior LIDAR experience –Geologist –GIS

18. Puget Sound LIDAR Consortium No formal structure One agenda One contract Separate payments Share data Release all data to public domain (www.GetItYourselfBob, to be hosted by UW library)

19. PSLC Tacoma Seattle

20. Tacoma Seattle LIDAR already flown to be flown this Winter ~$3.3M ~$3M

21. Toe Jam Hill fault scarp Waterman Point scarp beach uplifted during 900 AD earthquake 15 km west of Seattle

22. landslides southern Bainbridge Island

23. Uses for high-resolution topography Finding faults (earthquake frequency, kinematics) Geologic mapping Landslide hazards Flood hazards, groundwater infiltration, runoff modelling Fish habitat ?Precision forestry ?Noise propagation