MULTICOMPONENT VIBROSEISMIC PROFILING OVER HIGH VELOCITY GLACIAL GROUND: AN EXAMPLE FROM SOUTHERN ONTARIO
Bibliographic record
Abstract
A 3-D Quaternary mapping project conducted by the Ontario Geological Survey (OGS) in the southern part of Simcoe County involves borehole drilling, airborne geophysics, such as TDEM and magnetics and ground gravity surveys. Geophysical surveys are necessary to define the top of bedrock, including buried bedrock valleys and the architecture of overlying sediments for evaluating groundwater resources. In support of this project, the Geological Survey of Canada (GSC) carried out a three-line 21.2 km seismic reflection survey. Geophysical logging in two deep boreholes was undertaken to assist with the calibration of the seismic sections. The seismic survey was performed using an IVI “Minivib 1” source with a “landstreamer” three-component geophone array built by the GSC. The landstreamer consists of 72 - 3 kg metal sleds, spaced at 1.5 m, towed using low-stretch belts. Data were acquired with shot points every 4.5 m. The source vibrates a 140 kg mass in in-line (H1) horizontal mode, using a 7 second nonlinear logarithmic sweep of -2 DB/Oct from 20 to 300 Hz. This type of sweep increases the time spent in the low end of the sweep which has the effect to increase the low frequency energy to enhance shear body wave energy. Data were recorded using seven 24-channel Geometrics Geode engineering seismographs operated in the cab of the Minivib. Only the vertical component of the 24 geophones, furthest from the source, was recorded in order to obtain a better coverage of the P-wave data acquisition window. Uncorrelated records were collected to allow pre-whitening of the data and careful choice of the correlating function was the first step in the data processing sequence. P-wave sections were derived from processing the first 0.5 sec. (after correlation) of data acquired on the vertical geophones, while S-wave sections were produced using the in-line, H1, component over a correlated window of 2 seconds. Seismic sections were then correlated with borehole geophysical data. Interpretation of the equivalent compressional (P-) wave section permits delineation of seismic facies sequences. The P-wave velocity is an order of magnitude higher than the shearwave velocity and as a result, the vertical resolution of the section is lower. However, the acoustic impedance contrast with underlying materials (coarser sediments, tills or bedrock) is lower than in the case of shear-wave. The shear-wave data produce remarkably detailed sections over buried valleys down to 150 m.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".