California Institute of Technology Event API

openapi: 3.2.0
info:
  title: SCEDC FDSN Web Services (Caltech Seismological Laboratory) Event API
  version: 1.1.1
  summary: FDSN-standard seismic web services operated by the Southern California Earthquake Data Center at the Caltech Seismological Laboratory.
  description: The Southern California Earthquake Data Center (SCEDC) is operated by the Seismological Laboratory at the California Institute of Technology, on Caltech's own `caltech.edu` domain and Caltech-run infrastructure (service.scedc.caltech.edu resolves inside Caltech address space). It implements the International Federation of Digital Seismograph Networks (FDSN) web service specification — `fdsnws-event`, `fdsnws-station` and `fdsnws-dataselect`. This is genuinely institution-operated research infrastructure, not a vendor platform running under Caltech's name. This document is DERIVED by API Evangelist from live, unauthenticated probes; SCEDC publishes a WADL per service but no OpenAPI. Only operations actually observed returning data are described.
  contact:
    name: Southern California Earthquake Data Center, Caltech Seismological Laboratory
    url: https://scedc.caltech.edu/
servers:
- url: https://service.scedc.caltech.edu/fdsnws
  description: SCEDC production FDSN web services (verified live 2026-08-19)
tags:
- name: Event
  description: Earthquake event catalog queries (fdsnws-event).
paths:
  /event/1/version:
    get:
      operationId: getEventServiceVersion
      summary: Service version for fdsnws-event
      description: Verified live 2026-08-19 returning `1.1.1` as text/plain.
      tags:
      - Event
      responses:
        '200':
          description: Service version string.
          content:
            text/plain:
              schema:
                type: string
                examples:
                - 1.1.1
  /event/1/query:
    get:
      operationId: queryEvents
      summary: Query the earthquake event catalog
      description: Returns earthquakes matching the supplied time, magnitude and location filters. Verified live 2026-08-19 returning real SCEDC catalog rows as text/plain, and verified returning HTTP 400 with a structured plain-text error on a bad date.
      tags:
      - Event
      parameters:
      - name: starttime
        in: query
        description: ISO-8601 start of the time window.
        schema:
          type: string
      - name: endtime
        in: query
        description: ISO-8601 end of the time window.
        schema:
          type: string
      - name: minmagnitude
        in: query
        description: Minimum event magnitude.
        schema:
          type: number
      - name: maxmagnitude
        in: query
        description: Maximum event magnitude.
        schema:
          type: number
      - name: format
        in: query
        description: Response format. `text` and `xml` (QuakeML) observed.
        schema:
          type: string
          enum:
          - text
          - xml
      responses:
        '200':
          description: 'Pipe-delimited event rows (format=text) or QuakeML (format=xml). Observed columns: EventID, Time, Latitude, Longitude, Depth/km, Author, Catalog, ET, GT, MagType, Magnitude, MagAuthor, EventLocationName.'
          content:
            text/plain:
              schema:
                type: string
            application/xml:
              schema:
                type: string
        '204':
          description: No events matched the request. Observed on fdsnws-dataselect; FDSN-standard no-data response.
        '400':
          description: Malformed request. Verified live — returns text/plain carrying the error message, the submitted request, a timestamp and the service version.
          content:
            text/plain:
              schema:
                type: string
x-operator: institution
x-operator-rationale: service.scedc.caltech.edu is under the institution's own registrable domain and resolves to Caltech-operated hosts (134.4.54.0/24, Caltech address space). SCEDC is a Caltech Seismological Laboratory facility. FDSN is an open community standard the institution implements, not a vendor product it rents.
x-provenance:
  generated: '2026-08-19'
  method: derived
  derived-from: live unauthenticated HTTP probes, 2026-08-19
  source:
  - https://service.scedc.caltech.edu/fdsnws/station/1/version
  - https://service.scedc.caltech.edu/fdsnws/event/1/version
  - https://service.scedc.caltech.edu/fdsnws/dataselect/1/version
  - https://service.scedc.caltech.edu/fdsnws/dataselect/1/application.wadl
  - https://service.scedc.caltech.edu/fdsnws/station/1/query?net=CI&sta=PAS&level=station&format=text
  - https://service.scedc.caltech.edu/fdsnws/event/1/query?starttime=2026-08-01&endtime=2026-08-05&minmagnitude=3&format=text
  note: SCEDC publishes no OpenAPI. This description is API Evangelist's observation of the live services and must not be credited to Caltech as a published specification. The upstream normative contract is the FDSN web service specification.
x-standards:
- name: FDSN Web Services
  version: '1.1'
  url: https://www.fdsn.org/webservices/