{
  "access": "open",
  "cite_as": ["doi:10.1016/0031-9201(81)90046-7"],
  "creators": [
    {
      "name": "Adam M. Dziewonski"
    },
    {
      "name": "Don L. Anderson"
    }
  ],
  "curation": {
    "added": "2026-10-23",
    "quality_notes": ["ds.iris.edu now redirects to data.earthscope.org (2026-10-23)"],
    "source": "manual",
    "status": "curated"
  },
  "date_published": 1981,
  "description": "Radial profiles of density and seismic velocities of the Earth; the standard input for neutrino matter effects through the Earth.",
  "distributions": [
    {
      "formats": ["txt"],
      "host": "institutional",
      "label": "EarthScope (IRIS) Earth Model Collaboration",
      "role": "primary",
      "url": "https://ds.iris.edu/ds/products/emc-prem/"
    }
  ],
  "doi": "10.1016/0031-9201(81)90046-7",
  "id": "prem",
  "license": "none-stated",
  "model": {
    "formats": ["txt"],
    "quantities": ["density", "seismic velocities"],
    "validity": "0–6371 km radius; layered polynomial fits"
  },
  "newtrinos": {
    "modules": ["earth_layers"],
    "verifications": ["10.1016_0031-9201(81)90046-7"]
  },
  "short": "PREM (Dziewonski & Anderson 1981): radial density profile of the Earth used for matter effects",
  "sources": ["none"],
  "title": "Preliminary Reference Earth Model (PREM)",
  "topics": ["earth-model"],
  "type": "model",
  "url_landing": "https://ds.iris.edu/ds/products/emc-prem/"
}