---
title: "Seismic activity chain, one seismic zone"
method: GET
path: "/gauge/earthquake-region"
tags: ["gauge", "earthquake", "region", "usgs", "cross-source"]
---

# Seismic activity chain, one seismic zone

`GET /gauge/earthquake-region`

## Request

- Base URL: `https://api.truthbear.co`
- URL: `https://api.truthbear.co/gauge/earthquake-region`
- Auth: none declared

[3-LEG] Seismic activity chain, one seismic zone (?entity=california-san-andreas): leading swarm rate, USGS micro-event rate rising - DESCRIPTIVE and explicitly not a prediction -> current current max magnitude and count -> realized felt and impact reports (confirmation gate). A chain, not one reading: confidence = how many legs are lit, in order. Sources: USGS. Descriptive only, never a forecast or advice. No data -> 422 no_charge, not billed. Also searched as: seismic activity chain; quake zone conditions; ground shaking status; triangulated seismic activity.

## Query parameters

- `entity` 'california-san-andreas' | 'cascadia-pnw' | 'alaska-aleutians' | 'japan' | 'sumatra-indonesia' | 'philippines' | 'chile' | 'mexico' | 'central-america' | 'turkey-anatolia' | 'greece-italy-med' | 'iran' | 'nepal-himalaya' | 'new-zealand' | 'iceland' | 'png-solomon' | 'taiwan' | 'caribbean', required

## Response `200`

Paid response

- object
  - `nature` string, required: Neutrality statement: GAUGE supplies observations and trend description only - no judgement, no prediction, no recommendation
  - `entity` string: The object key of this bundle - the ?entity= you passed in
  - `name` string, nullable: Human-readable name of the object
  - `provenance` object, nullable: Data lineage: {served_from, data_as_of, oldest_leg_as_of, data_age_hours (frozen age, reference only), age_hours_now (age computed at request time - the real basis for freshness), freshness(fresh|recent|stale), freshness_basis (the cadence and threshold used for this row, as a string), dead_source (optional: upstream frozen or discontinued), data_lineage:[{signal,traceable_to,uncertainty,record_hash,...}], validation_status}. Freshness is cadence-aware, so monthly/quarterly/annual official lines are not misjudged against a 24h rule; the same basis is used by free /gauge/coverage. Buyers can trace back to the official source
  - `legs` object, required: CORE DELIVERY: per-leg readings, keyed by leg name (e.g. drought/heat/crop-vhi); each value carries signal_id/current/observed_at/data_age_hours/record_hash
  - `cross_line_narrative` string: Cross-line comparison narrative (purely descriptive; no judgement, no prediction)
  - `data_timespans` object[]: Per-leg observation time and hours elapsed since
  - `note` string: Conditional - endpoint-specific honest disclosure (limits, granularity, disclaimer); some endpoints omit it
  - `decision_points` object, nullable: {count, points:[{tag,current,swappable,how}], note} - decision points you can re-run with a swapped tag (one swapped tag = one call); leave it alone and the original context is the default, at no extra charge
  - `grade` string, nullable: Honest data-grade disclosure (e.g. "screening-level, not decision-grade")
  - `scope` string, nullable: Honest statement of scope and limits: monitoring is not forecasting, intelligence is not instruction, and the boundary of what is verifiable
  - `_citation` object, nullable: Offline-verifiable citation: {statement_type, not_advice:bool, claim, fact, source, record_hash, signature(Ed25519), key_id, issuer_DID(did:key), verify_url} - the trust root for zero-trust self-verification

## Other responses

- `402`: Payment Required
- `422`: No data for this query - no_charge:true, you are NOT billed

---

[API](https://skmtc.dev/truthbear/apis/truth-bear-verifiable-screening-intelligence-for-ai-agents-g.md) · [All operations](https://skmtc.dev/truthbear/apis/truth-bear-verifiable-screening-intelligence-for-ai-agents-g/llms.txt) · [OpenAPI document](https://skmtc.dev/truthbear/apis/truth-bear-verifiable-screening-intelligence-for-ai-agents-g/revisions/35744dfa4550?raw)