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Applications of Integrated Vessel-based LiDAR, Multibeam Bathymetry, and Geophysical Surveys for Geohazard Assessments and Site Characterization

James Fisher Engineering Geologist Todd Mitchell Survey Manager

July 2013

Overview

Introduction Why Emphasize Data Integration? Marine Survey Methods and Data Examples

Data Integration Examples MBES and LiDAR MBES, Magnetometer, Seismic Reflection Seismic Reflection and Marine Resistivity

Applications for Geohazard Assessment Coastal and Marine Infrastructure Rock Falls, Coastal Erosion, Slope Failure (Geomorphology) Karst

Summary Data Management and Integration using GIS Data Integration and “The Big Picture”

Why Emphasize Data Integration?

Topography

Geophysics

Bathymetry Geotechnics/ Geology

Fully Integrated Data Set

Integrated data sets improve mapping and geological characterization by helping to produce a complete picture of the “surface” and subsurface

Why Emphasize Data Integration? - Reduce Uncertainty (Risk Management)

Taking the Unknown Geological Model (Geophysics)

Geophysics and Geotechnical Data Integration

Design Model

Why Emphasize Data Integration?

Consider this

Why Emphasize Data Integration?

Now compare

Why Emphasize Data Integration?

LOOSE SAND

SOFT NC CLAY

INTERBEDDED SOFT CLAY &

SAND

STIFF OC CLAY AND DENSE SAND

INTERBEDDED CHANNEL INFILL

By planning an effective geophysical investigation first you can greatly aid future geotechnical investigations

Marine Survey Methods

Vessel-based LiDAR and Multibeam Bathymetry

Marine Survey Methods Vessel-based LiDAR and Multibeam Bathymetry

Marine Survey Methods

Vessel-based LiDAR and Multibeam Bathymetry (Norfolk, VA Example)

Higher Data Density Survey

Better-defined detail of sunken barge

Pilings

Lower Data Density Survey

Sunken barge

Marine Survey Methods

Vessel-based LiDAR and Multibeam Bathymetry A survey that integrates bathymetry with a topographic data can close the gap between surface and underwater topography.

Marine Survey Methods

Also, both are point cloud data sets (easily, and efficiently, collected and integrated)

Multibeam Bathymetry Echosounder (MBES) Data Sonar (sound) based ranging technology Wide coverage on both sides of vessel Millions of individual point observations

Marine Survey Methods

Also, both are point cloud data sets (easily, and efficiently, collected and integrated)

Mobile Laser Scanning Data (LiDAR) • Laser (light) based ranging technology • Scan land and features beside vessel • Millions of individual point observations

Marine Survey Methods

Also, both are point cloud data sets (easily, and efficiently, collected and integrated)

Marine Survey Methods

Marine Geophysical Methods

SSS Mag MBES

Boomer

Chirp

• Measure water depth and map riverbottom 1. Multibeam: hydrographic survey 2. Side scan sonar: image the riverbottom 3. Magnetometer: locate large ferrous or magnetic objects

• Subsurface mapping 4. Chirp seismic reflection: shallow stratigraphy and potentially buried objects 5. Multichannel, boomer seismic reflection: deeper stratigraphy and depth to bedrock

Marine Survey Methods

Marine Geophysical Methods – Side Scan Sonar

Marine Survey Methods

Marine Geophysical Methods – Side Scan Sonar

Marine Survey Methods

Marine Geophysical Methods - Seismic

• Chirp & Pinger: Upper 20 to 50ft • Boomer, Multichannel: Upper 500 to 1,500 ft • Sparker: Upper 2,000 ft • Air Guns: 5,000+ ft

Marine Survey Methods

Continuous Resistivity Profiling (CRP)

Marine Geophysical Methods - Resistivity

N

Resistivity Section (Below)

In this example, sediments permeated by fresh water has a higher resistivity (poorer conductor of electricity) than sediments permeated by salt water. The river bottom was mapped using a multibeam echosounder.

River Bottom (white line) Deeper Water Area

Marine Survey Methods

Marine Bottom Resistivity

Marine Geophysical Methods - Resistivity

Data Integration (Combining MBES and LiDAR Data Sets)

Data Integration (Combining MBES and LiDAR Data Sets)

Data Integration (Interpretation Utilizing Multiple Data Sets)

Pipeline Riverbottom

Magnetic Anomaly

Pipeline Surface Expression

Seismic Reflection

Magnetometer

Multibeam Bathymetry

Data Integration (Seismic and Resistivity)

Resistivity Profile

Seismic Refraction Profile

MASW (Surface Wave) Profile

Data Integration and Applications for Geohazard Assessment

Coastal and Marine Infrastructure – Bridge River Crossing (Missouri River)

Proposed Alignment

Existing Alignment

Data Integration and Applications for Geohazard Assessment

Coastal and Marine Infrastructure – Bridge River Crossing (Missouri River)

Data Integration and Applications for Geohazard Assessment

Coastal and Marine Infrastructure – Bridge River Crossing (CA)

Data Integration and Applications for Geohazard Assessment

Paleochannel (organics) – several historical explorations did not completely penetration (depth was unknown – costly to project)…But geophysics resolved the feature

Coastal and Marine Infrastructure – Bridge River Crossing (FL)

Data Integration and Applications for Geohazard Assessment

Rock Falls, Coastal Erosion, Slope Failure (Geomorphology)

Data Integration and Applications for Geohazard Assessment

Rock Falls, Coastal Erosion, Slope Failure (Geomorphology)

Data Integration and Applications for Geohazard Assessment

Rock Falls, Coastal Erosion, Slope Failure (Geomorphology)

Data Integration and Applications for Geohazard Assessment

Rock Falls, Coastal Erosion, Slope Failure (Geomorphology)

Data Integration and Applications for Geohazard Assessment

Rock Falls, Coastal Erosion, Slope Failure (Geomorphology)

Water Bottom

2D Resistivity (Adjacent Line)

N S

Interpreted Horizon

N S Seismic Horizon

Data Integration and Applications for Geohazard Assessment

Karst

Chirp Profile

Water Bottom

Data Integration and Applications for Geohazard Assessment

Karst Features

Data Integration and Applications for Geohazard Assessment

Karst Features

Data Integration and Applications for Geohazard Assessment

Karst Features

Summary –Data Management and Integration using GIS

Integrating Data Example (Tunnel Project)

Geophysics

Bathymetry, Side Scan Sonar, and Seismic

Data Integration and Applications for Geohazard Assessment

Incorporate Geophysical Data

Data Integration and Applications for Geohazard Assessment

Incorporate Geotechnical Data

Summary –Data Management and Integration using GIS

Incorporate Historical Data (for example, shorelines from nautical charts)

Summary –Data Management and Integration using GIS

Incorporate Historical Data (for example, shorelines from nautical charts)

Data Integration and Applications for Geohazard Assessment

Mudflat Area Structure Settlement Area

Laser Scanning

Multibeam Bathymetry

Seismic Profile

Summary –Data Integration and the (Geo) Big Picture

Summary - Why Emphasize Data Integration?

Taking the Unknown Geological Model (Geophysics)

Geophysics and Geotechnical Data Integration

Design Model

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Thank You! James Fisher jfisher@fugro.com Todd Mitchell tmitchell@fugro.com

Comments/Questions?