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Steve Raber, QSI Senior Program Manager
West Salt Creek
Landslide
GeCo in the Rockies Conference | September 24, 2014
Matt Morgan, Jon White, F. Scot
Fitzgerald and Karen Berry , Colorado
Geological Survey
• Massive landslide on May 25th, 2014
• Lower escarpment of the Grand Mesa
• Near Collbran, CO … about 40 miles east of here (Grand Junction) …
• 3 men killed …
• Current concerns: – potential pond failure/flood inundation
– continued movement
– proximity to active well heads
• High density LiDAR supported analyses
Landslide
Collbran
Grand Junction
TIMELINE
West Salt Creek Landslide
Sunday, May 25, 2014
Morning
• Precursor landslide -- east side of West
Salt Creek (noted by landowner)
• Disruption of irrigation ditch
• Second precursor slide -- west side of
creek
• Eyewitness noted moving ground /
crashing/toppling trees on upper valley
floor
Late afternoon
• Inspection by landowner’s son and county
public works employees
• 5:45 pm … 3 landslide pulses within 3
minutes
West
East
3 well heads
Courtesy of Colorado Geological Survey
660 ft
2.8 mi
1,700 ft
Courtesy of Colorado Geological Survey
Interagency Response • Mesa County (Sheriff’s office,
Emergency Mgmt., Public
Works, other agencies)
• FEMA
• Colorado Office of Emergency
Management
• U.S. Forest Service
• U.S. Geological Survey
• National Geospatial-
Intelligence Agency (NGA)
• Colorado School of Mines
(CSM); Colorado Geological
Survey (CGS)
• U.S. Army Corp of
Engineers (USACE)
• USDA National Resources
Conservation Service
(NRCS)
• NOAA
• Colorado Mesa University
• Div. of Water Res./Dam
Safety Program
• Colo. Water Cons. Board
• Town of Collbran
Following Week • Monday, May 26 – Memorial Day
• Monitoring tools installed (USFS,
USGS, Mesa County)
– Unmanned Aerial Systems (UAS) –
image acquisition
• Inundation/flood modeling (USGS,
USACE, others)
• LiDAR coverage (CGS/Colorado
State)
– Quantum Spatial (QSI) – Acquisition partner
• 3D modeling (CGS, CSM)
• Slope stability analyses (CSM)
• Mapping (USGS, CGS)
LiDAR Discussions (Following Week cont.)
• QSI - CGS discuss
rapid response for
LiDAR acquisition
• LiDAR study area
determined
• Response time
determined
• Mobilization planning
• Proposal dev’t /
Contracting
• CGS emergency
access to funds
Courtesy of Colorado Geological Survey
CGS Need for LiDAR
• Critical: snapshot of slide immediately following event,
for baseline elevation and change-detection analyses
• Modeling of slide for potential inundation of Collbran
• Stability analyses of upper rotated block
• Additional landslide hazard mapping around slide area
• Calculation of slide volume, areas of excavation and
deposition
• Elevation data for placement of roadways, canals, and
other engineered features
LIDAR ACQUISITION & PROCESSING
West Salt Creek Landslide
Area of Interest
Debated Options
Final AOI 48,118 acres
Acquisition Plan
• Mobilize aircraft from
nearby project site
(Partenavia P68)
• Start collection on Sunday,
June 1
• Simultaneously acquire
control points
• Coordinate with onsite
incident command (OIC)
– Mesa County Sherriff
– Temporary flight
restriction (TFR)
LiDAR Specs
• 48,118 acres
• 12 hrs flying time
• 1400m (~4600’) AGL
• 10,200’ terrain elevation
• ALS70 Sensor
• O2 required for flight crew
LiDAR Specifications Summary
Multi-Swath Pulse Density ≥ 8 pulses/m2
Scan Angle ≤30o (+/-15o from Nadir)
Returns Collected Per Laser Pulse Up to 4
Intensity Range 1-255
Swath Overlap 50% side-lap (100% overlap)
GPS PDOP During Acquisition ≤3.0
GPS Satellite Constellation ≥6
Maximum GPS Baseline 13 nautical miles
Accuracyz (1.96 ), slope <20o < 20 cm
Vertical Accuracy ( ), slope <20o ≤ 9 cm
Horizontal Accuracy ( ) ≤ 30 cm
Deliverables • LiDAR
– Point Cloud
– All returns, Las 1.2 format
– Point files: X,Y,Z, Return Intensity, Return Number, Point Classification (ground,
default), Scan Angle, GPS Time
• Surface Models
– Highest Hit DEM, 1m resolution, ESRI Grid format
– Intensity Images, 0.5m resolution, GeoTiff format
• Vectors
– Survey Boundary, shapefile format
– Tiling delineations, shapefile format
• Reporting
– Methods, Results, Accuracy Assessments, pdf and Word format
– Ground Check Points, shapefile format
– FGDC-compliant Metadata
Delivery Schedule
• NTP: Fri 5/30/14
• Acquisition
– Start: Sun 6/1/14
– 80% complete: Mon 6/2/14
– 100% complete: Tues 6/3/14
• Processing
– Start: Wed 6/4/14
– Final deliverables: Mon 6/16/14
• ~18 Days from NTP to delivery!
PRELIMINARY FINDINGS
West Salt Creek Landslide
LiDAR Surface Model
LiDAR Bare Earth Surface
General • Classified as an extremely rapid rock/debris avalanche and
debris flow
• Precipitation was slightly above average (morning of 5/25:
1.5" in 3.5 hours)
• Moved 2.8 miles, down 2200 vertical feet, from about 9,600’
to 7,400’ elev.
– Length 7 times the vertical height
• Flows of disaggregated and pulverized rock occurred as cascading stacked pulses (3), mostly constrained by West
Salt Creek valley
• Landslide deposit at toe was only slightly damp with steep slope at edge (~40 degrees)
General (cont.)
• Debris/rock avalanche covered 599 acres (0.95
square miles)
• 3 fatalities; remains not yet found
• Pick-up truck and 4-wheeler also missing
• At assumed truck location at end of road, slide is
1,900’ wide and debris deposit up to 125’ thick
• Current ground movements very small, mostly in
terms of vertical consolidation and settlement (F.
Kochevar, Mesa Co.)
West Salt Creek
Oxy Hawkins
Ranch
#14-4A
#14-3A
#11-13C
Assumed truck location
Courtesy of Colorado Geological Survey
~2,900 ft
~450 ft
Cross sections generated from
4m IfSAR DEM
provided by
FEMA and post-
landslide LiDAR
Area of
evacuation
Tire tracks of
missing truck
Geologic
• Eastern portion of ancient landslide failed in
recent past (1984, according to Hawkins family)
• Upper scarp mapped in regional landslide study
by CGS (Soule, 1988)
• The May 2014 landslide occurred at same
ancient scarp of a geologically recent landslide
complex
• Full geologic characterization conducted by
CGS, USGS, and Colorado Mesa University
Mechanisms of Failure
• Trigger: 2,700’ wide rotational block failure
• Caused rock avalanches and debris flows
• Block failed along pre-existing ancient scarp
• Rotational failure and back-tilting of upper block
created depression below main scarp of
landslide
• Eyewitness: entire landslide was in-place
within a 15-minute time frame. Seismic wave
indicated major block failures within 3 min.
Slide Morphology
• Assessed using:
– High resolution aerial photography (UAS)
• County collected photography during rescue and
recovery period (when slide considered unsafe)
• Now available on GoogleEarth (3 months after
slide)
– High density LiDAR hill-shade
– Locations of red soil remnants -- reveals
some sense of sequence of deposits
Photogrammetry
Courtesy of Mesa County Sheriff’s office
100s of UAS images
Long-Term Threats/Concerns • Stability of upper rotated block
• Reactivation and retrogressive failures above existing head scarp
• Threat of subsequent mud/debris flows
– Breach and rapid outlet of ponded water
– Mini-tsunamis
• Inundation of Salt Creek and flood threat downstream
• Spread of landslide toe to Salt Creek
• Burial and shearing of Oxy well heads
Well heads
Tanks and other infra-
structure relocated here
Diversion berms and other
earthwork to direct flows
away from well pad
CURRENT ACTIVITY
West Salt Creek Landslide
Pond Monitoring • Water flowed into depression due
to spring run-off, at high rate
– up to 15 to 30 cfs; current rate ~2-4
cfs
– Pond: ~1,500 ac-ft (65,000,000 ft3)
• Level stopped rising at end of
June
• Seeping occurring from base of
upper block and small ponds
appearing in center of slide and
below east ridgeline
• Still no water seeping from
landslide toe as of September 5
West view (8/21/14)
Future publications
• CGS completing preliminary report of the
landslide fall 2014
• USGS to complete final paper and detailed
map of landslide in future publication
QUANTUM SPATIAL
Geospatial Services
The Power of 3
Data Information Understanding
LANDSLIDES
Landslide Experience
• Oso, WA landslide LiDAR response (2014) –
WA DOT; pre- and post-slide data
• Oregon Department of Geology And Mineral
Industries (DoGAMI) testing of entire
Vernonia 7.5’ quad (west of Portland, OR)
• California power company – identification of
landslides in 32 mile corridor (Lake Tahoe
area) … for remediation purposes
• Additional pilot studies and smaller projects
Methods/Tools Development
• Landslide Support (what we do)
– Detection and risk (semi-automated methods)
– Rapid response (data acquisition)
– Detailed analytics
– Impact analyses
– Monitoring (LiDAR)
• Detection methods
– Use of open source GIS, Python, C++, and Java scripting
– Pattern recognition algorithm developed by Chang/Lin
– Extrapolate conditions based on modeling of small training sites
– Polygon labeling and attribution – landslide metrics
• Future: development of terrain failure hazard maps
Landslide Analytics
• Tool generates multiple layers based on
topography; highlights surface feature
aberrations
– ID sensitive areas previously unknown,
unmapped, unmanaged
– IDs areas of high, medium and low risk terrain
failure
– Determine areas of concern, reveal new potential
risks, and help experts focus resources in
vulnerable areas
Polygons attributed with susceptibility information
Field Tested, Geologist Approved
QSI has achieved 95% accuracy for landslide detection
Quantum Spatial automated result
DoGAMI delineation
Field Survey
Case Study
Quantum Spatial automated
Landslide delineation
Transmission Line
California power company – landslide detection for mitigation/remediation
Questions
Acknowledgements:
Quantum Spatial greatly appreciates the support of Matthew Morgan, Senior Research Geologist at the Colorado School of Mines (CSM), Colorado Geological Survey (CGS), for a large portion of the content of this presentation.