{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/us-geological-survey/main/json-schema/usgs-earthquake-feature-schema.json",
  "title": "USGS Earthquake Feature",
  "description": "GeoJSON Feature representing a single USGS earthquake catalog event",
  "type": "object",
  "properties": {
    "type": {
      "type": "string",
      "const": "Feature"
    },
    "id": {
      "type": "string",
      "description": "Unique USGS event ID (network code + event code)"
    },
    "geometry": {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "const": "Point"
        },
        "coordinates": {
          "type": "array",
          "description": "[longitude, latitude, depth_km]",
          "items": {"type": "number"},
          "minItems": 3,
          "maxItems": 3
        }
      }
    },
    "properties": {
      "type": "object",
      "properties": {
        "mag": {
          "type": ["number", "null"],
          "description": "Magnitude of the earthquake"
        },
        "place": {
          "type": ["string", "null"],
          "description": "Named geographic region near the epicenter"
        },
        "time": {
          "type": "integer",
          "description": "Event time in milliseconds since Unix epoch (UTC)"
        },
        "updated": {
          "type": "integer",
          "description": "Last update time in milliseconds since epoch"
        },
        "tz": {
          "type": ["integer", "null"],
          "description": "Timezone offset in minutes from UTC at the epicenter"
        },
        "url": {
          "type": "string",
          "description": "URL to the USGS event page"
        },
        "detail": {
          "type": "string",
          "description": "URL to detailed GeoJSON for this event"
        },
        "felt": {
          "type": ["integer", "null"],
          "description": "Number of Did-You-Feel-It (DYFI) responses submitted"
        },
        "cdi": {
          "type": ["number", "null"],
          "description": "Maximum reported intensity from DYFI community reports (1-10 MMI scale)"
        },
        "mmi": {
          "type": ["number", "null"],
          "description": "Maximum estimated instrumental intensity from ShakeMap (1-10 MMI scale)"
        },
        "alert": {
          "type": ["string", "null"],
          "description": "PAGER alert level: green, yellow, orange, or red",
          "enum": ["green", "yellow", "orange", "red", null]
        },
        "status": {
          "type": "string",
          "description": "Review status of the event",
          "enum": ["automatic", "reviewed", "deleted"]
        },
        "tsunami": {
          "type": "integer",
          "description": "1 if event is in a tsunamigenic region, 0 otherwise",
          "enum": [0, 1]
        },
        "sig": {
          "type": "integer",
          "description": "Significance score (0-1000) based on magnitude, DYFI, and alert level",
          "minimum": 0,
          "maximum": 1000
        },
        "net": {
          "type": "string",
          "description": "Network code of the authoritative data contributor"
        },
        "code": {
          "type": "string",
          "description": "Event code assigned by the contributing network"
        },
        "ids": {
          "type": "string",
          "description": "Comma-separated list of event IDs from all contributing networks"
        },
        "sources": {
          "type": "string",
          "description": "Comma-separated list of contributing network codes"
        },
        "types": {
          "type": "string",
          "description": "Comma-separated list of product types available for this event"
        },
        "nst": {
          "type": ["integer", "null"],
          "description": "Number of seismic stations used to determine location"
        },
        "dmin": {
          "type": ["number", "null"],
          "description": "Horizontal distance in degrees to nearest seismic station"
        },
        "rms": {
          "type": ["number", "null"],
          "description": "Root-mean-square travel time residual in seconds"
        },
        "gap": {
          "type": ["number", "null"],
          "description": "Largest azimuthal gap between adjacent stations in degrees"
        },
        "magType": {
          "type": ["string", "null"],
          "description": "Method used to calculate the preferred magnitude (mb, ml, mw, etc.)"
        },
        "type": {
          "type": "string",
          "description": "Type of seismic event"
        },
        "title": {
          "type": "string",
          "description": "Human-readable title combining magnitude and location"
        }
      },
      "required": ["mag", "place", "time", "status", "sig", "net", "code", "type"]
    }
  },
  "required": ["type", "id", "geometry", "properties"]
}