# 📐 L2 Spec — Vibration-Based Damage Detection (modal analysis NDT) Mismatch-Only Spec
**ID:** `L2-124-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-124`](/artifact/l1/L1-124)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41554216
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| Snr db | dB | 0.0 – 40.0 |
| N modes | — | 3 – 50 |
| N sensors | — | 4 – 500 |
| T acquire s | s | 5 – 3600 |
| Sensor noise | — | 0.0 – 0.2 |
| Mode truncation | — | 0.0 – 0.5 |
| Environmental variability | — | 0.0 – 0.2 |
| Operational load variation | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
12.0 + 0.3 * SNR_dB - 10.0 * environmental_variability - 8.0 * operational_load_variation - 6.0 * mode_truncation
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`bea4c0897d227367f231b40ffbf06e4ad23bac13145467f32bb13546cc868b2e`
## 5. On-chain Registration
- **Chain hash:** `0x8e8372f55d11605b92dc0ac5c3c618fee5f05eb8f989d4fa975327c0a969ccf2`
- **Chain tx hash:** `0x2cfd3b73fb600cb4465b72ecabf5dfca708840828638eb486f3b253e6ff57ff2`
- **Chain block:** `41554216`
---
## File Mapping
This bundle consists of: `L2-124-001.md`, `L2-124-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-124-001.md` | Source of truth — edit this | Human or LLM |
| `L2-124-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-124-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._