Raber west saltcreeklandslide

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


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


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


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


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


~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


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

[email protected]

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.

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Raber west saltcreeklandslide