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A Time-Slice of History

Updated: Jan 31

As prize winners of The Great British SUMO Survey, SUMO undertook an exploration to provide geophysical information into a historic Cloister and Chapter House at Rochester Cathedral.

Rochester Cathedral, Kent

Above: Rochester Cathedral, Kent.

The client brief:

  • SUMO were asked us to provide as much information as obtainable to the full extent of the Cloister and Chapterhouse, and the possible relationship with the former Roman city wall which defined the south side to the extant Cloister.

The process:

  • SUMO carried out a Ground Penetrating Radar (GPR) survey and Laser Scan survey as earlier work at the cathedral had demonstrated how effective the techniques can be in such ecclesiastical environments.

  • The data was analysed using specialist software. In addition to manual abstraction to the radargrams, so-called ‘time slices’ were produced which reveal remains at differing depths below the surface being surveyed.

The results:

  • The GPR data fulfilled the client’s requirements and identified a complex of linear and isolated features, probably graves.

  • The potential archaeological remains are probably associated with 11th and 12th century Chapter Houses, early Norman Cloister arrangement, 19th century Prebendal House, medieval buildings and Dormitory range. The remaining responses are modern and include potential services and evidence of tree roots.


"I am delighted with the GPR survey SUMO Geophysics carried out for us at Rochester Cathedral. This can be a difficult place to work, with many complications over use, access and safeguarding. SUMO’s team were a model of professionalism throughout, which made the operational side so much easier to deal with. The results are absolutely fantastic, surpassing my most optimistic hopes for what we might achieve. I went into this project with clear aims (or at least hopes) that we might end up with a better understanding of how the medieval cloister had evolved. To find such clear evidence for a previously unknown early Norman cloister underneath the existing 12th-century one, as well as unexpected elements of the Cellarer’s Range, was a real bonus. It was also a pleasure working with the team who carried out the detailed analysis and interpretation of the survey data, which was an ideal collaboration between us. Top marks all round - thank you!"

Graham Keevill, Cathedral Archaeologist - Keevill Heritage Lt


Technical notes:

  • The survey penetration depth reached approximately 2.30m - readings were taken at 0.05m intervals along each traverse set 0.08m apart. The survey was completed using a High Density Array (MALA mini MIRA) system which employs a 400MHz antenna.

  • Two of the main advantages of radar are its ability to give information of depth as well as work through a variety of surfaces, even cluttered environments which normally prevent other geophysical techniques being used.

GPR data

Above: GPR data collected at Rochester Cathedral by SUMO Geophysics.

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