Leaders in Shear-Wave Technologies

See what’s underground
before you dig.

Every city hums — traffic, machinery, wind. Terēan®’s ReMi® technology listens to that everyday noise and turns it into a shear-wave velocity image of the ground beneath your site. Fast, non-invasive, and ASCE 7-22 compliant.

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ASCE 7-22 compliant site classification Results in under 30 minutes Images beyond 1,000 ft Works at noisy urban sites Passive + active sources Invented in 2001 by Prof. John Louie Backed by hundreds of peer-reviewed publications

I work in

Mining & Resources

Engineering & Geotechnical

Energy & Geothermal

Research & Education

How it works

The noise is the signal.

Vibrations from traffic, construction and wind travel through the ground as surface waves — and how fast they travel depends on how stiff the ground is. Lay out a line of geophones, record a few minutes of everyday noise plus a few hammer hits, and ReMi® turns that racket into a velocity profile of what’s below: soft soils, low-velocity zones, faults, and the depth to solid rock.

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01

Lay out the line

A 24-channel line of geophones can be set up, recorded and wrapped up in about 30 minutes — on soil, pavement, slopes or tight urban lots.
02

Record the noise

Typically 10–15 minutes of recording. Busy site? Even better — ambient noise adds energy. One-click QC confirms data quality before you leave.
03

See the subsurface

VsSurf software produces a 1D shear-wave profile and an ASCE 7-22 site class report in under 30 minutes — and the same data builds a full 2D section.

<30 min

Field data to site-class report

1,000+ ft

Imaging depth with Deep ReMi®

2001

Year Prof. Louie invented ReMi®

100 ft

Vs depth ASCE 7-22 requires

What you can see

One survey. The whole picture underground.

Real VsSurf 2D shear-wave sections — cooler colors are softer, slower material; warmer colors are stiffer and faster.

VsSurf ReMi 2dS® — Depth to Bedrock

Depth to Bedrock

The vertical distance from the surface to solid rock is critical for engineering, mining, and construction. VsSurf ReMi® provides fast, cost-effective mapping that delivers data for foundation stability, groundwater flow, and excavation planning.

Building-code ready

ASCE 7-22 requires Site Class to be determined from shear-wave velocity (Vs) in the upper 100 ft.

Under ASCE 7-22, measured surface shear-wave velocity is the preferred method for site classification. Our products meet all requirements of ASCE/SEI 7-22 Seismic Design (Chapters 11–23) — and results are accepted by building authorities around the world.

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ASCE 7-22 SITE CLASS · Vs100 Sample result Vs100 = 1,125 ft/s → Site Class CD

E–DE Soft clays & loose sands
D–CD Stiff soils & dense sands
C–BC Very dense soil to soft rock
B–A Medium hard to hard rock

Why Terēan

Proven methods, backed by decades of expertise.

01 / 04

Quick and easy to use

Our solutions give every user the ability to obtain geologic and geophysical subsurface information, then autogenerate a report with an accurate, ASCE 7-22 compliant seismic site classification in less than 30 minutes. The analysis is conceptually simple — train your field crews and leave the field knowing you have a result that is accepted by building authorities around the world.

The results from the last job I did turned out great – the Vs100 came within 3 ft/s of seismic CPT down to 100 feet.

Tyler Bernius, PESenior Engineer — Intertek-PSI

02 / 04

Accepted in industry and academia

VsSurf ReMi® software enables small and large institutions to give their students the practical training that the industry demands while facilitating research projects. VsSurf analyses are backed by hundreds of peer-reviewed publications.

ReMi is my go-to method for shear wave velocity to 100'+ (usually 300'+) even above DHS, CHS, SCPT and refraction surveys… Many thanks for your white papers and expert support thru the decades!

Ryan Coggins, P.E.Senior Geotechnical Engineer — Kiewit Engineering Group, Inc.

03 / 04

Built for traffic-heavy urban sites

VsSurf software gives users a ground investigation method that is proven to work in traffic-heavy urban areas. Find the depth to interfaces, profile landslide blocks, assess aquifer volume, and evaluate rippability at the noisiest sites.

Let me start by saying that the VsSurf software is very user-friendly! Secondly, the training and support that comes with VsSurf is unmatched! … The expertise of the Terēan Team is simply amazing!

Sam Abdollahian, PhD, P.E.Geotechnical Department Manager — ECS Southeast, LLC

04 / 04

Works with a variety of data

VsSurf software works with geophone arrays, DAS fibers, small and large scale recording setups, and both interferometric and non-interferometric data.

We consider the project-specific measurement of Vs an integral part of our geotechnical site characterization for seismic applications and look forward to continuing interaction with Dr. Louie and Terēan.

Stephen E. Dickenson, Ph.D., P.E., B.C.Principal Engineer — New Albion Geotechnical, Inc.

Prof. John N. Louie, Chief Technology Officer and Chief Geophysicist

Prof. John N. Louie Co-Founder, CTO & Chief Geophysicist

Where it started

In 2001, Prof. John Louie invented the Refraction Microtremor method.

It serves as the foundation of our seismic imaging solutions. With Prof. Louie leading our science — more than 40 years of teaching and research in geophysics and seismology — you can expect proven methods backed by decades of expertise.

“Even home builders might now be able to afford a shear-velocity evaluation at every home site.”
Louie, J.N. — “Faster, Better: Shear-Wave Velocity to 100 Meters Depth from Refraction Microtremor Arrays.” BSSA, 2001

Meet the Team Publications & testimonials →

Industries

From foundations to geothermal fields.

Mining & Resources

Reduce costs by covering your mineral resource ground reliably and rapidly — depth to bedrock, faults, excavation and hauling costs, ore and waste rock zones, and the condition of your earthen structures.

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Engineering & Geotechnical

Reliably and quickly determine critical subsurface information for less — earthquake ground-shaking potential per the IBC, depth and velocity of subsurface layers, and rheologic properties of earth and rock.

Explore Engineering →

Energy & Geothermal

Non-invasively image basin-wide earth structure to over 10,000 ft (3,200 m) depth, to assist in developing drill targets for producing energy resources in commercial quantities.

Explore Energy →