Pick P and S Arrivals
45 minPick arrivals to 0.1 s on three or more stations.
Intermediate1-2 hours
Epicenter Triangulation Guide
Learn epicenter triangulation from scratch with a clear step-by-step workflow, recommended tools, safety guidelines, and expert tips.
intro labsamateur networks
Workflow
Compute S-P Intervals
30 minLarger Δt means greater epicentral distance.
Draw Distance Circles
30 minConvert Δt to distance; circle each station on map.
Estimate Depth and Origin Time
30 minTrial depths minimizing residual misfit.
Checklist
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Planning
Preparation
Safety
Execution
Reference Materials
S-P MethodStandard
Local Δ ≈ (S−P seconds) × 8 km for average crust — calibrate regionally.
Travel TimeFormula
Iterate depth to minimize Σ(residual²) on P arrivals.
VP/VS RatiosTable
Crustal references.
| Region | VP/VS | Note |
|---|---|---|
| Continental | 1.73 | Lab default |
| Subduction | 1.80 | Higher Poisson |
| Sediment | 1.70 | Basins |
Measure Twice
Double-check all measurements before committing — small errors compound across multiple steps.
Consistency Check
Verify uniformity across all pieces — inconsistency is the most common quality issue.
Ventilation
Ensure adequate ventilation when working with chemicals, adhesives, or heated materials.
Safety Notes
- Amateur locations are approximate — cite uncertainty.
- Do not alert public from single-station picks.