# 📐 L2 Spec — Glacial Isostatic Adjustment (GIA) — post-glacial rebound Mismatch-Only Spec
**ID:** `L2-287-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-287`](/artifact/l1/L1-287)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554068
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| N gps | — | 10 – 10000 |
| Snr db | dB | 0 – 40 |
| N layers | — | 5 – 1000 |
| N load history | — | 100 – 1000000 |
| Ice history error | — | 0.0 – 0.3 |
| Mantle viscosity error | — | 0.0 – 0.5 |
| Lithosphere thickness error | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
1.0 + 5.0*ice_history_error + 5.0*mantle_viscosity_error + 3.0*lithosphere_thickness_error
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |
## 4. Fingerprint
`dc91b7f543eb4ecb826039fde1cb8936bce506e084e8cce71920305c68ad5be6`
## 5. On-chain Registration
- **Chain hash:** `0xdbe77a8bfd1665653167f0b5cf77d623146e48260bd9b9d000715ebce4fa6fa8`
- **Chain tx hash:** `0x645b5e6dc8c515472c8f73de27209b56255969b3eb8530b18c71dc8aa68163eb`
- **Chain block:** `41554068`
---
## File Mapping
This bundle consists of: `L2-287-001.md`, `L2-287-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-287-001.md` | Source of truth — edit this | Human or LLM |
| `L2-287-001.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 `L2-287-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._