{"subject":"earthquakes","resolved":true,"sources":[{"id":"usgs-eq","name":"USGS Earthquake Hazards Program","url":"https://earthquake.usgs.gov","license":"US Government work \u2014 public domain","license_url":"https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits","commercial_use":true,"cadence":"real-time (minutes after an event)","category":"hazards","tools":["earthquakes"]}],"commercially_clean":true,"chain_of_custody":[{"step":1,"stage":"origin","what":"USGS Earthquake Hazards Program (US Government work \u2014 public domain)","detail":"The authoritative publisher. https://earthquake.usgs.gov"},{"step":2,"stage":"ingest","what":"Dynamic Feed polls the source on its update cadence","detail":"USGS Earthquake Hazards Program: real-time (minutes after an event)"},{"step":3,"stage":"normalize","what":"Normalized + stamped","detail":"Each row gets a provenance envelope (source, source_url, reported_at, measured_at, age_seconds) and a freshness envelope (state live/stale/unavailable, observed_at, age_seconds, max_age_seconds). No value is invented; missing data is marked unavailable."},{"step":4,"stage":"serve","what":"Delivered over REST or the keyless MCP endpoint","detail":"You can cite the source and verify the number against the official URL above."}],"verify":{"official_urls":["https://earthquake.usgs.gov"],"license_urls":["https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits"],"signatures":null},"note":"Chain of custody for this subject. Every step is auditable; every source is verified for commercial use and redistribution.","signature":{"alg":"Ed25519","key_id":"df-ed25519-3a52a473cde2","canonicalization":"json-sorted-compact","sig":"HX5iwV7U9NiKCRPTmutsEXyNcQX6llchvwLWfC9EHKzQKnUasXQ2guHrdzDpVcGsbOCS2Ed2l8FFjpD8N6_uBg=="}}