# 📐  L2 Spec — Seismic Travel-Time Tomography — ray-based velocity imaging Mismatch-Only Spec

**ID:** `L2-272-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-272`](/artifact/l1/L1-272)

> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554054

---

## 1. Domain Ω

**Type:** `range`

| Parameter | Unit | Range |
|---|---|---|
| H | px | 32 – 1024 |
| W | px | 32 – 1024 |
| Z | — | 16 – 512 |
| Snr db | dB | 0 – 40 |
| N sources | — | 4 – 1024 |
| N receivers | — | 16 – 8192 |
| Picker error | — | 0.0 – 0.05 |
| Source error | — | 0.0 – 0.05 |
| Ray coverage gaps | — | 0.0 – 0.5 |
| Velocity prior error | — | 0.0 – 0.2 |

## 2. Tolerance (ε)

**Type:** `fn`

```
2.5 + 20.0*velocity_prior_error + 10.0*source_error + 10.0*picker_error + 8.0*ray_coverage_gaps
```

## 3. Difficulty

| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |

## 4. Fingerprint

`265d26de800820b40d4dc275b16bb6bbb3aff098d92c11c5d7c6e887c70a5f0a`

## 5. On-chain Registration

- **Chain hash:** `0x8f9a42ede0f0f00661db61e7298d3a455178966b639e81ba6c28b4c81dd7f0dc`
- **Chain tx hash:** `0x7f257455ade89fe8ebc95f28f39bed7bfa59eaa122c2d8dd2cf4817cf8ebae0c`
- **Chain block:** `41554054`

---

## File Mapping

This bundle consists of: `L2-272-001.md`, `L2-272-001.json`.

| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-272-001.md` | Source of truth — edit this | Human or LLM |
| `L2-272-001.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 `L2-272-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._