Ground

What's under your feet?

The rock beneath your postcode and how many million years old it is, whether it holds water, the boreholes drilled within a kilometre, and the nearest recent earthquakes, from the British Geological Survey's open maps and records.

  • Bedrock and deposits
  • The aquifer below
  • Boreholes within 1 km
  • Nearest earthquakes

How this works

The British Geological Survey maps the whole country twice over: the bedrock, the solid rock that formed over hundreds of millions of years, and the superficial deposits, the clay, sand, gravel and peat that rivers, ice and the sea have left on top in the last couple of million years. The page asks the BGS’s OpenGeoscience services what both maps show at your postcode, which aquifer class the hydrogeological map gives the rock, which of the million-plus borehole records in the national index lie within a kilometre, and which of the earthquakes in the BGS seismology feed are nearest. Maps are cached a month, the earthquake feed an hour.

Sources

  • BGS Geology 625k (bedrock and superficial), BGS Hydrogeology 625k, BGS borehole index and BGS seismology recent earthquakes. Contains British Geological Survey materials © UKRI 2026. Open Government Licence v3.
  • Postcodes: postcodes.io / ONS Postcode Directory (OGL v3).

For interest, not for engineering: anyone building, digging or drilling should use the detailed 1:50,000 mapping and a proper site investigation.