Why does seismic site class matter for my project?

It directly sets the earthquake design forces your structural engineer must use. An incorrect or assumed site class can result in an under- or over-designed structure.

No. It requires only surface geophone placement, making it suitable for sites where excavation is restricted.

Can MASW be combined with CPT or DPSH?

Yes. Combining methods cross-validates stiffness, strength, and stratigraphic findings within a single ground model.

Multi-channel Analysis of Seismic Waves (MASW)

ASCE 7-16 / IBC 1613.1

Determine your site’s Seismic Site Class without drilling or excavation using MASW, one of the most critical inputs for earthquake-resistant structural design.

MASW delivered entirely in-house, from acquisition to interpretation

What Is MASW?

Multichannel Analysis of Surface Waves (MASW) is a non-intrusive geophysical method that uses a 24-channel PASI seismic acquisition system and 24 vertical 4.5 Hz geophones deployed along a survey line. An impact source generates surface waves, and analysis of their dispersion produces a layered shear-wave velocity (Vs) profile with depth, all without drilling or excavation.

Seismic Site Classification

The measured shear-wave velocity profile is used to calculate Vs30, the time-averaged shear-wave velocity in the upper 30 m of the ground. Under ASCE 7-16 and IBC 1613.1, Vs30 forms the basis for Seismic Site Classification, which directly influences the design response spectrum and the seismic forces a structure must be designed to resist.

Combined MASW field setup showing the seismic cable, 4.5Hz geophones, and PASI seismic acquisition system deployed along a survey line

Applications

Seismic site classification for structural design

Shear-wave velocity profiling to support seismic and geotechnical design

Verification of design assumptions using site-specific geophysical data

Why MASW

Optimize structural design costs

Site-specific seismic characterization can reduce unnecessary conservatism where ground conditions justify it.

Rapid, non-intrusive deployment

No drilling or excavation is required, minimizing site disruption and investigation costs.

Reduce uncertainty before construction

Provides the measured ground data engineers need to make confident, code-compliant seismic design decisions.

Deliverables

Dispersion curve and inverted Vs profile

Vs30 and Seismic Site Class determination

Design response spectrum, where commissioned

Case Study Spotlight

Antigua · Aviation · Rock Coring + MASW

Signature Aviation FBO, Antigua

MASW combined with rock coring and laboratory testing at a live international airport, establishing seismic site class and rock mass strength parameters for the new FBO terminal footprint.

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Our Services

Cone Penetration Testing (CPT)ASTM D5778-20 Dynamic Probing Super Heavy (DPSH)ISO 22476-2:2005 Pile Integrity Testing (PIT)In-house Materials TestingMulti-method Our EquipmentIn-house

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