Practising engineers — not staff writers — covering GPR, near-surface geophysics, dam safety, tunnelling, and the policy environment that frames them. Published bi-weekly. Read by 5,000+ subscribers across nine countries.
The Subsurface Brief
Field-validated writing on subsurface engineering.
Featured · Tunnelling · Dam Safety
Crosshole and Cross-Face Seismic Tomography: How They Work, Where They Are Used, and Their Practical Limitations
A large concrete dam has undergone grouting for years, yet seepage continues downstream. Boreholes provide only isolated information and visual inspection cannot reveal what is happening inside the…Read more
2 Feb 202616 min read
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Dam Safety
Subsurface Utility Engineering (SUE): How It Works, Why It Matters, and the Practical Challenges of Underground Utility Management
A city road is excavated for a new metro corridor. Within hours, the contractor damages an unrecorded fiber optic cable, interrupts telecommunications across several districts, and floods part of the… Read more
10 Oct 202655 minTunnelling · Dam Safety
Seismic Refraction and Seismic Refraction Tomography: How They Work, Where They Are Used, and Their Practical Limitations
A tunnel excavation suddenly encounters a heavily fractured, water-bearing zone that was never identified during drilling. Excavation slows dramatically, support requirements increase, and project… Read more
10 Oct 202615 min
Ground Penetrating Radar
Ground Penetrating Radar (GPR): How It Works, Where It's Used, and What It Can't Do
A construction crew is about to drill through a reinforced concrete slab. Nobody has seen the original drawings, and the drawings that do exist are thirty years old. One wrong hole and they hit a… Read more
2 Feb 2026101 minTunnelling · Dam Safety
Crosshole Seismic Test and Downhole Seismic Test: How They Work, Where They Are Used, and Their Practical Limitations
A large hydropower project is preparing for the design of an underground powerhouse cavern. Boreholes indicate "rock," but the engineering team still does not know how competent or… Read more
10 Oct 202515 minDam Safety · Tunnelling
Multi-Channel Analysis of Surface Waves (MASW): How It Works, Where It Is Used, and Its Practical Limitations
A major infrastructure project is being planned on soft alluvial ground. Boreholes indicate alternating layers of clay and sand, but engineers still do not clearly understand the stiffness variation… Read more
5 May 202015 minDam Safety · Tunnelling
Electrical Resistivity Imaging (ERI): How It Works, Where It's Used, and What It Cannot Do
A dam has been leaking for years. The seepage is visible downstream, but nobody knows where the water is actually travelling beneath the structure. Drilling a few boreholes has not solved the problem… Read more
10 Oct 200014 min