USGS Earthquake Delta Monitor

Watchlist-based delta monitor of the USGS FDSN Earthquake Event Service: get alerted only when new earthquakes matching your magnitude / place / region watchlist occur since the last run — "free when nothing changes", pay only on signal. Built on public USGS data (no API key, no signup, no credentials, no proxies).

What it does

The Actor polls the official, public USGS FDSN Earthquake Event Service (https://earthquake.usgs.gov/fdsnws/event/1/query) for earthquakes in a date window you choose (default: the last 7 days, magnitude >= 2.5, worldwide) and emits one dataset item per newly observed earthquake matching your watchlist:

• New earthquakes matching a watchlist entry (min magnitude / place / region) → one dataset item per event, tagged newSinceLastRun: true
• Nothing changed since the last run → no dataset items at all (free when nothing changes)

State is checkpointed per watchlist item in the Actor default key-value store, so repeat runs only surface genuinely new earthquakes.

Search terms this Actor answers

• USGS earthquake monitor
• earthquake alert watchlist
• seismic activity tracker
• USGS FDSN earthquake API
• earthquake delta monitor
• recent earthquakes watchlist

Who it is for

Property insurers and cat-risk desks, emergency-management contractors, commercial property and asset owners, and news desks covering natural disasters. Early earthquake signal has direct loss-mitigation value and is typically bought from insurance risk and operations budgets or emergency-management service contracts.

Data source

Public US government data, keyless, no login, no proxies:

https://earthquake.usgs.gov/fdsnws/event/1/

This Actor queries https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&starttime=...&endtime=...&minmagnitude=...&limit=... (server-side min magnitude, optional place / regioncode filters) with deterministic client-side re-checking of the magnitude / place / region filters. No LLMs, no commercial inference, no credentials, no proxies inside the product.

Input

See actor/.actor/input_schema.json.

• watchlist (array of objects, optional, default []): each entry is {minMag, place, region}. place is a case-insensitive substring matched against the USGS place description; region is either a numeric Flinn-Engdahl region code (sent to USGS server-side) or a substring matched against the place description. Leave empty to monitor every earthquake worldwide at the top-level min magnitude. One checkpoint is kept per entry.
• sinceDays (integer, 1-365, default 7): how far back to look on the first run; repeat runs only emit events newer than the last checked state.
• minMag (number, >= 0, default 2.5): default minimum magnitude applied to watchlist entries that do not set their own.
• maxResults (integer, 1-200, default 25): cap of new earthquake alerts per run.

Example input:

{
  "watchlist": [
    { "minMag": 4.5, "place": "California" },
    { "minMag": 5.0, "region": "51" }
  ],
  "sinceDays": 7,
  "maxResults": 25
}

Output

One dataset item per newly observed earthquake matching a watchlist entry since the last run (see actor/.actor/dataset_schema.json), including event id, time, magnitude, place, coordinates, depth, alert level, significance, network, matched watchlist entry, and the USGS source link.

Pricing

Published as a pay-per-event Apify Store listing: $0.0001 per Actor start + $0.005 per alert (earthquake-change event). Unchanged replays emit nothing, so runs with no new earthquakes are free.

Verification

• pytest actor/tests — deterministic tests, no network (fakes httpx responses and the Apify default key-value store)
• ruff check actor/ — 0 errors
• Default input returns >0 dataset items against the live USGS FDSN API in under 5 minutes (evidenced by a real Apify run of the pushed build)

Distinctness

USGS seismic-events delta monitoring — distinct from the other apex-nexus Actors (SEC filings, FDA/NHTSA/FSIS/CPSC recalls, CFPB complaints, state campaign finance, USDA/BLS economic reports, NWS weather alerts, Federal Register). No Apify Store listing is a USGS earthquake delta watchlist monitor; incumbents are one-shot pay-per-event search scrapers with no checkpoint and no "free when nothing changes" behavior.