Multi-channel Analysis of Surface Waves (MASW)
Over 22 years providing New Zealand with industry-leading MASW surveying non-invasive shear-wave velocity profiling: 1D, 2D and 3D
Southern Geophysical were among the first to introduce MASW and shear wave reflection in New Zealand and remain leaders in advanced planted and towed array surveys. With flexible configurations from compact 48-channel layouts to extended 96-channel arrays, we deliver 1D soundings, 2D velocity profiles, and 3D models that support geotechnical and seismic design. We follow the latest guidelines for surface-wave analysis recognised by the New Zealand Geotechnical Society (NZGS) and continually refine our work as the underlying science evolves.
For alternative approaches to Vs30 and deeper site response investigations, see our Shear Wave & Vs30 Surveys page.
Why undertake MASW with Southern Geophysical?
Depth of investigation: active MASW typically reaches ~3 to 30 m, determined by about half the deployed array length. For deeper characterisation, we supplement with passive surface-wave methods (HVSR, ReMi, passive MASW), extending penetration well beyond the active range.
Array flexibility: shorter layouts provide high-resolution shallow targets; extended arrays capture deeper horizons.
Landstreamer efficiency: our preferred system in accessible terrain, delivering rapid coverage with minimal disruption.
Rayleigh and Love wave capability: MASW can be acquired using Rayleigh waves, Love waves, or both in combination to improve model confidence.
Shear-wave reflection surveys: available alongside MASW to image the upper ~50 m in greater detail than P-wave reflection, providing direct shear-wave velocity information.
Data integration: outputs can be directly imported into Leapfrog® and other geological modelling platforms.
Best-practice methods: processed using the latest software and recommendations, supported by ongoing training and development.
Urban capability: including night-time surveys under council noise limits, proven in CBD environments across New Zealand.
We operate the broadest range of surface-wave systems in New Zealand; from compact high-resolution near surface arrays through to large-scale planted, towed, and distributed passive systems. This flexibility allows us to design surveys that balance penetration depth, resolution, and efficiency, whatever the environment.
Depth & Resolution
Active MASW surveying typically penetrates 3 - 30 m, depending on array length, source energy, and ground conditions. Shorter arrays provide finer lateral/vertical resolution at shallow depths, while longer arrays extend penetration. Where projects demand greater depth, MASW can be combined with passive methods (HVSR, ReMi, passive MASW) to extend imaging well beyond the active range.
We consult with clients to define the target depth of interest, ensuring survey design is optimised for both depth and resolution rather than simply chasing maximum penetration.
Integration & Project Experience
MASW results can be strengthened by combining with shear-wave reflection, seismic refraction, and calibration against downhole, CPT and borehole data, producing more robust velocity models.
Southern Geophysical has delivered MASW surveys across New Zealand and the Pacific for infrastructure, renewable energy, land development, and seismic site classification. Following the Canterbury Earthquake Sequence and Kaikoura Earthquake, we completed some of the country’s largest MASW campaigns in Christchurch and Wellington, providing critical velocity data for recovery, redevelopment, and future planning in urban centres.
Our Commitment
Since 2003, we have delivered MASW surveys ranging from small developments to major infrastructure corridors. Southern Geophysical brings unmatched experience, modern systems, and best-practice methods to every project. We consult closely with clients to design surveys that address the real questions at hand, ensuring results that are both reliable and practical.
As the science has advanced, we have continually improved our technology, training, and processing systems to maintain best practice and deliver industry-leading outcomes.
References and Guidelines We Follow
Southern Geophysical’s MASW practice is aligned with both New Zealand and international research, including but not limited to:
Foti, S., Hollender, F., Garofalo, F., Albarello, D., Asten, M., Bard, P. Y., ... & Socco, V. (2018). Guidelines for the good practice of surface wave analysis: a product of the InterPACIFIC project. Bulletin of Earthquake Engineering, 16(6), 2367-2420.
Ivanov, J., Miller, R. D., Hoch, A. M., Peterie, S. L., & Morton, S. (2019). Surface wave analysis sensitivity to assumptions in a-priori information. In SEG International Exposition and 89th Annual Meeting (pp. 5030-5034).
Louie, J. N. (2001). Faster, better: shear-wave velocity to 100 meters depth from refraction microtremor arrays. Bulletin of the Seismological Society of America, 91(2), 347-364.
Park, C. B., Miller, R. D., & Xia, J. (1999). Multichannel analysis of surface waves. Geophysics, 64(3), 800-808.
How can we help?
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