The effects of seasonal variation on archaeologicaldetection using earth resistance: Preliminary results                fr...
Introduction                                                                         Introduction• A study to aid archaeol...
The DART Project                                                                              Introduction• Detection of A...
The DART Project• The Universities of Leeds and Nottingham                            Introduction   • Hyper-spectral and ...
Test Areas• 4 Test Areas                                              Introduction   • All ditches (old field boundaries o...
Harnhill, Cirencester                        Introduction                        DART Project                        Seaso...
Harnhill, Cirencester           IntroductionFluxgate gradiometer greyscale   DART ProjectQuarry FieldHeavy clay geology   ...
Harnhill, Cirencester           IntroductionFluxgate gradiometer greyscale   DART ProjectQuarry FieldHeavy clay geology   ...
Harnhill, Cirencester                                             Introduction            Fluxgate gradiometer greyscale  ...
Harnhill, Cirencester                                             Introduction            Fluxgate gradiometer greyscale  ...
Quarry Field, Cirencester - Heavy Clay           Ground-truthing                                                  Introduc...
Fieldwork                   Monthly Surveys – Twin Probe                                                                  ...
FieldworkMonthly Surveys – FlashRes64 ERI                      • New technology – usually       Introduction              ...
Monthly Surveys - FlashRes64                                       Introduction                                       DART...
IntroductionERT                      DART Project(FlashRes64 transects)                         Seasonality               ...
IntroductionERT                      DART Project(FlashRes64 transects)                         Seasonality               ...
IntroductionERT                      DART Project(FlashRes64 transects)                         Seasonality               ...
IntroductionEarth Resistance            FlashRes64(Multiplexed area survey)                            DART Project       ...
IntroductionEarth Resistance            FlashRes64(Multiplexed area survey)                            DART Project       ...
IntroductionEarth Resistance            DART Project(Multiplexed area survey)                            Seasonality      ...
IntroductionEarth Resistance            DART Project(Multiplexed area survey)                            Seasonality      ...
Monthly Surveys – Twin Probe                                                              Introduction                    ...
Initial analysis - Earth Resistance        Characteristic Seasonal Responses? Free Draining                               ...
Characteristic Seasonal Responses? – Free Draining             Magnitude of anomaly at Cherry Copse (a=0.25m) after median...
Characteristic Seasonal Responses? – Free Draining                Magnitude of anomaly at Cherry Copse (a=0.25m) after med...
Characteristic Seasonal Responses? – clay-on-clay                                                                         ...
Characteristic Seasoanl Responses? – clay-on-clay   12                                                                    ...
Characteristic Seasoanl Responses? – clay-on-clay   12                                                                    ...
Summer
Autumn
Winter
Change in resistivity through the    profile from June 2011
Change in resistivity through the           profile from June 2011Summer:-Generally increased resistivity (around 10-20% h...
Change in resistivity through the              profile from June 2011Autumn:-Resistivity decreased to a depth of 1m toJune...
Change in resistivity through the               profile from June 2011Autumn:-Resistivity decreased to a depth of 1m toJun...
So it must have been a really wet             winter, right?Well………
So it must have been a really wet             winter, right?Well………
10                                                 15                                                                 20  ...
Thoughts so far…                                                                  Introduction• Resistivity decreases from...
Proposed Work                                                                                IntroductionLots more to do… ...
IntroductionThank you for listening                                                  FlashRes64                           ...
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The effects of seasonal variation on archaeological detection using earth resistance: Preliminary results from an ongoing study

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A presentation by Rob Fry at the 2012 Computer Applications in Archaeology conference in Southampton

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The effects of seasonal variation on archaeological detection using earth resistance: Preliminary results from an ongoing study

  1. 1. The effects of seasonal variation on archaeologicaldetection using earth resistance: Preliminary results from an ongoing study Robert Fry Chris Gaffney, Anthony Beck, David Stott 2012
  2. 2. Introduction Introduction• A study to aid archaeological detection • Resistivity / Electromagnetics / Radar / TDR / Remote Sensing DART Project • Prediction / Reliability / Detection / Interpretation Seasonality• Why? •Known unknowns: Fieldwork ‘The problem with resistance data is that the ‘normal’ response can vary with the season’ Initial Data Gaffney and Gater 2003:27 Proposed work• Why now? •The DART Project
  3. 3. The DART Project Introduction• Detection of Archaeological remains using Remotesensing Techniques DART Project • The multi-temporal problems associated with heritage detection are not just a domain of electrical resistance surveys • Hyper-spectral imagery Seasonality • EM surveys • Aerial photographic evidence Fieldwork • In association with the Universities of Leeds, Birmingham, Initial Data Winchester and Nottingham • Civil engineering, computing, geophysics, remote sensing, soil engineering, data analysis and interpretation, knowledge engineering Proposed work • A multi-disciplinary framework to solve a multi-faceted problem
  4. 4. The DART Project• The Universities of Leeds and Nottingham Introduction • Hyper-spectral and spectral detection problems • Land use, Crop type/vigour/stress, Soil geology, Weather DART Project Seasonality• The University of Bradford • Detection Problems associated with Electrical Resistance Fieldwork • Soil geology, Weather, Soil composition Initial Data Proposed work• The University of Birmingham • Soil Permittivity, Conductivity, and weather data analysis and comparison with GPR survey • Soil engineering properties, Soil geology, Weather
  5. 5. Test Areas• 4 Test Areas Introduction • All ditches (old field boundaries or archaeological) DART Project• 2 Situated on Clay soils Seasonality• 2 Situated on ‘Free draining’ soils Fieldwork Initial Data• 2 Locations • Harnhill, Cirencester Proposed work • Diddington, Cambridgeshire
  6. 6. Harnhill, Cirencester Introduction DART Project Seasonality Fieldwork Initial Data Proposed work
  7. 7. Harnhill, Cirencester IntroductionFluxgate gradiometer greyscale DART ProjectQuarry FieldHeavy clay geology Seasonality Fieldwork Initial Data Proposed work
  8. 8. Harnhill, Cirencester IntroductionFluxgate gradiometer greyscale DART ProjectQuarry FieldHeavy clay geology Seasonality Fieldwork Initial Data Proposed work
  9. 9. Harnhill, Cirencester Introduction Fluxgate gradiometer greyscale DART Project Cherry Copse Weathered limestone bedrock Seasonality Fieldwork Initial Data Proposed work
  10. 10. Harnhill, Cirencester Introduction Fluxgate gradiometer greyscale DART Project Cherry Copse Weathered limestone bedrock Seasonality Fieldwork Initial Data Proposed work
  11. 11. Quarry Field, Cirencester - Heavy Clay Ground-truthing Introduction DART Project Seasonality FieldworkCherry Copse, Cirencester - Weathered Limestone Initial Data Proposed work
  12. 12. Fieldwork Monthly Surveys – Twin Probe Introduction FlashRes64 DART Project Seasonality Fieldwork Initial Data• 10m survey grid Proposed•0.5 x 0.5m resolution work•4 multiplexed probe separations which can be equated with different volumesand in theory, depths of soil
  13. 13. FieldworkMonthly Surveys – FlashRes64 ERI • New technology – usually Introduction a geological/hydrological investigation. DART Project • C.15,000 measurements in 16 minutes Seasonality • Collects resistivity data in section through the ground Fieldwork Initial Data Proposed work
  14. 14. Monthly Surveys - FlashRes64 Introduction DART Project Seasonality Fieldwork Initial Data Proposed workDitch
  15. 15. IntroductionERT DART Project(FlashRes64 transects) Seasonality Fieldwork Initial Data Proposed work
  16. 16. IntroductionERT DART Project(FlashRes64 transects) Seasonality Fieldwork Initial Data Proposed work
  17. 17. IntroductionERT DART Project(FlashRes64 transects) Seasonality Fieldwork Initial Data Proposed work
  18. 18. IntroductionEarth Resistance FlashRes64(Multiplexed area survey) DART Project Seasonality Fieldwork Initial Data Proposed work
  19. 19. IntroductionEarth Resistance FlashRes64(Multiplexed area survey) DART Project Seasonality Fieldwork Initial Data Proposed work
  20. 20. IntroductionEarth Resistance DART Project(Multiplexed area survey) Seasonality Fieldwork Initial Data Proposed work
  21. 21. IntroductionEarth Resistance DART Project(Multiplexed area survey) Seasonality Fieldwork Initial Data Proposed work
  22. 22. Monthly Surveys – Twin Probe Introduction DART Project Seasonality Fieldwork Initial Data Proposed work Excavation trenchKite photography courtesy of David Stott – Leeds University
  23. 23. Initial analysis - Earth Resistance Characteristic Seasonal Responses? Free Draining Introduction Cherry Copse (free-draining) Seasonal Relationship (a = 0.25m) 190 DART Project 170 Seasonality June 0.25m Ave 150 July 0.25m Ave September 0.25m Ave 130 October 0.25m Ave FieldworkOhms November 0.25m Ave 110 December 0.25m Ave January 0.25m Ave Initial Data Feburary 0.25m Ave 90 Proposed 70 work 50
  24. 24. Characteristic Seasonal Responses? – Free Draining Magnitude of anomaly at Cherry Copse (a=0.25m) after median filtering Introduction 20 15 DART Project 10 5 Seasonality 0Ohms -5 Fieldwork -10 -15 Initial Data -20 -25 Proposed -30 work June Median July Median September Median October Median November Median December Median January Median Feburary Median
  25. 25. Characteristic Seasonal Responses? – Free Draining Magnitude of anomaly at Cherry Copse (a=0.25m) after median filtering Introduction 20 15 DART Project 10 5 Seasonality 0 Characteristic response over seasonsOhms -5 20 Fieldwork -10 15 -15 10 Initial Data -20 5 -25 0 "Summer" Proposed Ohms -30 -5 "Autumn" work June Median July Median September Median October Median "Winter" -10 November Median December Median January Median Feburary Median -15 -20 -25 -30
  26. 26. Characteristic Seasonal Responses? – clay-on-clay Introduction Quarry Field (clay) Seasonal Relationship (a = 0.25m) 90 DART Project 80 Seasonality June 0.25 Ave 70 July 0.25 Ave September 0.25 Ave Fieldwork October 0.25 AveOhms 60 November 0.25 Ave December 0.25 Ave Initial Data Janurary 0.25 Ave 50 Feburary 0.25 Ave Proposed 40 work 30
  27. 27. Characteristic Seasoanl Responses? – clay-on-clay 12 Introduction Magnitude of anomaly at Quarry Field (a=0.25m) after median filtering 10 8 DART Project 6 4 SeasonalityOhms 2 0 Fieldwork -2 -4 Initial Data -6 -8 Proposed work June Median July Median October Median September Median November Median December Median Janurary Median Feburary Median
  28. 28. Characteristic Seasoanl Responses? – clay-on-clay 12 Introduction Magnitude of anomaly at Quarry Field (a=0.25m) after median filtering 10 8 DART Project 6 Characteristic response over seasons 4 Seasonality 12Ohms 2 10 0 Fieldwork 8 -2 6 -4 Initial Data 4 Q"Summer" -6 2 Q"Autumn" -8 Q"Winter" Proposed 0 work 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 -2 June Median July Median October Median September Median -4 November Median December Median Janurary Median Feburary Median -6 -8
  29. 29. Summer
  30. 30. Autumn
  31. 31. Winter
  32. 32. Change in resistivity through the profile from June 2011
  33. 33. Change in resistivity through the profile from June 2011Summer:-Generally increased resistivity (around 10-20% higher than June)-Between June and July the area around the feature decreased in resistivity
  34. 34. Change in resistivity through the profile from June 2011Autumn:-Resistivity decreased to a depth of 1m toJune- Earth below 1m in depth remained thesame resistivity as in the summer months
  35. 35. Change in resistivity through the profile from June 2011Autumn:-Resistivity decreased to a depth of 1m toJuneWinter:- Earth below 1m in depth remained thesame resistivity as inin resistivity at surface-Further decreasing the summer months(over 75% lower than in June)- Decrease resistivity at depths over 1 metrefor the first time
  36. 36. So it must have been a really wet winter, right?Well………
  37. 37. So it must have been a really wet winter, right?Well………
  38. 38. 10 15 20 25 30 0 5 1.5.11 8.5.11 15.5.11 22.5.11 29.5.11 5.6.11 Well……… 12.6.11 19.6.11 26.6.11 3.7.11 10.7.11 17.7.11 24.7.11 31.7.11 7.8.11 • Moisture change? 14.8.11 21.8.11 • Temperature change? 28.8.11 4.9.11 11.9.11 18.9.11 25.9.11 2.10.11 9.10.1116.10.1123.10.11 winter, right?30.10.11 6.11.1113.11.1120.11.1127.11.11 4.12.1111.12.11 • Large decrease in resistivity from summer into winter…18.12.11 So it must have been a really wet Survey Rainfall (mm) Temp max (⁰C)
  39. 39. Thoughts so far… Introduction• Resistivity decreases from summer to winter DART Project• Seasonal data variation does exist – there are step changes between different seasons Seasonality Fieldwork• The measured response is greatest in the summer Initial Data• The decrease in resistivity at c.0.5-1m depths a function of temperature (not rainfall) in autumn Proposed work• The continuing decrease in resistivity at greater depths over winter due to both temperature and rainfall (?)
  40. 40. Proposed Work IntroductionLots more to do… DART Project-Continuing monthly surveys until autumn 2012 Seasonality- The influence of weather on the detection capabilities of the systems - Weather stations - in situ TDR and Temperature probes Fieldwork- How does the resistivity response link to the aerial response in detection?Is there a link? Initial Data- Further studies planed for diurnal variations and induced weather events Proposed work
  41. 41. IntroductionThank you for listening FlashRes64 DART Project Seasonality FieldworkThe DART Project website: www.dartproject.info Initial Data Proposed work Robert Fry r.j.fry@student.bradford.ac.uk

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