Notes from the field
Notes
Short pieces on the methods, the standards and the things that go wrong underground. Written for the people who have to make the decision, not for other geophysicists.
Nine tons of what?
Radar images geometry. Turning that geometry into a tonnage requires an assumption about what the material is — and that assumption, not the survey, decides most of the answer.
October 13, 2026 · 5 min read Seismic · DeliverablesWhat a site class report should contain
Thin reports are not obviously thin until a plan reviewer asks a question you cannot answer. The dispersion curve and the inversion are what the thin ones leave out.
October 3, 2026 · 4 min read Seismic · MethodMASW or ReMi: where each one fails
Both produce a shear-wave velocity profile. They break down under opposite site conditions, which is why the firm you ask tends to decide the answer.
October 3, 2026 · 4 min read Seismic · CodeASCE 7-22 quietly made borings insufficient for site class
Nine site classes instead of six, and shear-wave velocity is now the only accepted basis. If your geotechnical report assigns a site class from blow counts, it no longer complies.
August 11, 2026 · 4 min read Magnetics · RenewablesThe wells nobody recorded, under the sites everybody is developing
Estimates put undocumented orphaned wells in the United States between 310,000 and 800,000. Solar and wind developments cover large acreage in precisely the country where they were drilled.
July 28, 2026 · 5 min read Electrical · InterpretationThe section is smoother than the ground
A resistivity section looks like a picture of the subsurface. It is not. It is the simplest arrangement of colour that would have produced the readings.
October 15, 2026 · 5 min read Laser scanning · TerminologyLiDAR or laser scanning? The same physics, a different job
The two words get used interchangeably and then a specification asks for one and gets the other. The distinction is not the instrument.
October 15, 2026 · 4 min read Borehole · LoggingWhich log answers which question, and the window for asking
A borehole is the most expensive thing on most site investigations and the shortest-lived. Once it is cased or backfilled, most of what it could have told you is gone.
October 15, 2026 · 5 min read Thermal · Cable designThe assumed 90, and the two ways it is wrong
Almost every buried cable in the country is sized against a thermal resistivity nobody measured. Sometimes that costs money. Sometimes it costs the cable.
October 15, 2026 · 5 min read Radar · CemeteriesWhat radar can and cannot say about a grave
Radar does not find remains. It finds the hole somebody dug, and the difference decides what a cemetery survey can honestly tell you.
October 12, 2026 · 4 min read SUE · StandardsWhat a utility quality level actually promises
QL-D, QL-C, QL-B and QL-A are not grades of effort. They describe where the information came from, and only one of them involves seeing the pipe.
July 16, 2026 · 4 min read