A point in space, a moment in time: towards an integrated view of the Santorini eruption

Stuart Dunn

Centre for e-Research, King’s College London

Santorini Chronology Workshop, Aarhus, 10th November 2007

Objectives:

• Overview of tephra fallout

• Consistent representation of data

• Estimation of bulk volume of ejecta

• Towards ‘encoding archaeology’ - associating archaeological and natural sciences data spatially and temporally

Constructing a geodatabase of Theran tephraPlace name: Santorini archipelago (northern caldera basin)

Deposit type: sea-floor sediment ( 400m)

Grid reference: not given

Area: -

Thickness: 40m

Deposition method: composite

Archaeological context: -

Comments: -

Literature: Woods Hole Oceanographic Institute Research Vessel Chain Cruise # 61, ref. no. 67 – 34.

(26)

Place name: Hagia Varvara

Grid reference: 25.46 E; 35.29 N

Deposit type: pumice layer

Area: unknown

Thickness: 5 – 10 cm

Deposition method: waterborne or human agency

Archaeological context: LM IA or possibly IB cup included in pumice layer and

filled with p umice, immediately below a s urface layer

containing LM III pottery.

Comments: Very badly eroded by modern tourist pathways. Illegal

development in the area has further damaged the

stratigraphy. As far as the author is a ware, however, this is

the only inst ance where a vesse l is included in situ with the

volcanic material.

Literature: Blackman 2001: 138; Müller Celka 1996: 928 – 8; also Müller

Celka personal communication, 6/8/2001.

Constructing a geodatabase of Theran tephra

Constructing a geodatabase of Theran tephra

Constructing a geodatabase of Theran tephra: problems

• Accuracy and (versus) precision

• Georeferencing from heterogeneous formats

Constructing a geodatabase of Theran tephra: problems

• Accuracy and (versus) precision

• Georeferencing from heterogeneous formats and sources

• Assessing deposition process

• Harmonizing points, sections and stratigraphies

• Georeferencing places

-formal, based on lat/long or other mathematical expressions

-Informal, based on placenames, and/or where no formal mathematical identifier is present

24.87

34.87

Estimation of bulk volume of ejecta

• Geographical Information Systems (GIS)

• Triangulated Irregular Network (TIN)

‘Conceptually like bending a sheet of rubber to pass through the point, while minimizing the curvature of the surface’

- total raster cell value of 132,508,783.441, or…

• This is a maximum estimate - c. 90-100 km3 is nearer the mark

- 134.343 +/- 4 km3

Towards ‘encoding archaeology’

• Parallel between referencing points on the earth’s surface and referencing points in time

• Relative and absolute

• Development of reasoning models to manage space and time

M. Doerr et al 2004, fig 1.

The CIDOC-CRM

www.ahessc.ac.uk/briefing_paper

M. Doerr et al 2004, fig 2.

Towards ‘encoding archaeology: ‘meetings’

“The concept of “meetings is extraordinarily powerful: Chronology concerns and involves events … “Dating” an object actually means approximating the coherence volume of some event(s) in which the object was present.”

-Supporting Chronological Reasoning in Archaeology, Doerr et al 2004

Towards ‘encoding archaeology: ‘meetings’

• A. Deposition of a tephra deposit

• B. Production of a LMIA cup in Crete - predates A, but with smaller ‘coherence volume’.

• D. C14-datable fire destruction

“The concept of “meetings is extraordinarily powerful: Chronology concerns and involves events … “Dating” an object actually means approximating the coherence volume of some event(s) in which the object was present.”

- Doerr et al 2004

M. Doerr et al 2004, fig 2.

• C. Deposition of cup

A future project: Agent-based modelling

A future project: Agent-based modelling

After Giuseppe Trautteur and Raniero Virgilio

To Conclude…

stuart.dunn@kcl.ac.uk