Geotechnical Geophysics
MASW — Seismic Surface Wave Survey
Non-invasive shear wave velocity profiling for geotechnical design.
Overview
Multichannel Analysis of Surface Waves (MASW) is a seismic method that determines the shear wave velocity (Vs) profile of the subsurface. RIIM's MASW surveys provide geotechnical engineers with critical soil stiffness data — including Vs30 for seismic site classification — without the need for boreholes or intrusive investigation.
How It Works
A seismic source generates surface waves that are recorded by a linear array of geophones. The recorded data is processed using frequency-wavenumber (f-k) or phase velocity analysis to extract the dispersion curve, which is then inverted to produce a 1D or 2D shear wave velocity profile. Results are used to classify site conditions and assess liquefaction potential.
Applications
- Pre-construction utility detection and conflict mapping
- Concrete scanning for rebar, post-tension cables, and voids
- Road and pavement layer thickness assessment
- Void and sinkhole detection beneath structures
- Archaeological and forensic subsurface investigation
- Oil and gas facility utility verification
- Live utility tracing in congested urban corridors
- Gas main and water main route verification
- Power cable and telecoms duct tracing
- Depth profiling of metallic utilities
- Verification of as-built utility records
- Pre-excavation safety surveys
- BIM Level 2 / Level 3 utility integration
- Clash detection for new infrastructure design
- Asset management database population
- 12D model creation for road and rail projects
- GIS utility layer creation and maintenance
- As-built utility record verification and update
- Offshore pipeline and cable route surveys
- Port and harbour development site investigations
- Seabed obstruction and wreck detection
- Dredging volume and pre/post-dredge surveys
- Subsea utility detection and mapping
- Environmental baseline seabed surveys
- Road and pavement void detection beneath carriageways
- Building foundation cavity assessment
- Karst and dissolution feature mapping
- Abandoned mine and tunnel detection
- Sinkhole risk assessment for development sites
- Pre-construction geohazard screening
- Void and cavity detection at depth
- Geological structure and fault mapping
- Salt dome and evaporite dissolution detection
- Buried valley and palaeochannel identification
- Mineral exploration and resource assessment
- Infrastructure site geohazard screening
- Seismic site classification (Vs30) for building codes
- Soil stiffness profiling for foundation design
- Liquefaction potential assessment
- Bedrock depth and rippability assessment
- Pavement and embankment condition assessment
- Geotechnical site characterisation
- Topographic survey and digital terrain modelling
- Construction progress monitoring and volumetrics
- Corridor mapping for pipelines, roads, and power lines
- Stockpile volume calculation
- Coastal and environmental change monitoring
- Infrastructure inspection and condition assessment
- Groundwater exploration and aquifer mapping
- Contamination plume delineation and monitoring
- Void, cavity, and karst feature detection
- Geological mapping and stratigraphic profiling
- Landfill and waste body characterisation
- Slope stability and embankment assessment
Deliverables
- Georeferenced utility plan drawings (AutoCAD / GIS)
- Depth profiles and radargram data files
- PAS-128 / ASCE 38-22 compliant survey reports
- 3D point cloud utility models (on request)
- BIM-ready IFC / DWG utility layers
- Georeferenced utility route drawings
- Depth and signal strength logs
- Combined GPR + EPL integrated utility plans
- PAS-128 / ASCE 38-22 compliant survey reports
- 2D utility plans in AutoCAD DWG / DXF
- 3D utility models in IFC / Revit / Navisworks
- 12D model files for civil design integration
- GIS shapefiles and geodatabases
- Utility conflict reports and clash matrices
- Bathymetric charts and digital elevation models
- Sub-bottom profile sections and interpretations
- Side-scan sonar mosaics and seabed classification
- Magnetic anomaly maps
- Integrated marine geophysics reports
- Cavity risk maps and anomaly location plans
- GPR radargrams and ERT resistivity sections
- Interpreted geophysical cross-sections
- Geohazard assessment report with risk classification
- Remediation recommendations
- Bouguer anomaly maps and gravity profiles
- 2D / 2.5D density models
- Geological interpretation maps
- Integrated geophysical interpretation report
- Recommendations for follow-up investigation
- 1D Vs profiles and 2D Vs cross-sections
- Vs30 values and seismic site class designation
- Dispersion curves and inversion models
- Geotechnical interpretation report
- Liquefaction susceptibility assessment (on request)
- High-resolution orthomosaic imagery
- Digital Surface Model (DSM) and Digital Terrain Model (DTM)
- Dense point cloud (LAS / LAZ format)
- 3D mesh models and textured surfaces
- Contour plans and volumetric reports
- 2D resistivity inversion sections
- 3D resistivity volume models (on request)
- Geological and hydrogeological interpretation
- Time-lapse ERT monitoring results (on request)
- Integrated geophysical investigation report
Common Questions