2013 SSS-Bath

Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Kiril Velkovsky
Survey team members:
Hristina Angelova
Vesselin Draganov
Naiden Prahov
Peter Petrov
Kiril Velkovsky
Dragomir Garbov
Atanas Orachev
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
September and October 2013 the Centre of Underwater archaeology Sozopol has
launched a remote sensing survey in the area of sought Bulgarian black sea part. The
survey incorporated bathymetrical measurements and side scanning monitoring.
The subject of the survey has been following tasks to be completed:
− To setup operational the new equipment of the centre of underwater archaeology and to
create and tested a methodology of surveys especially for archaeology;
− To cover some areas where we do not have data from previous conducted surveys;
− To be used side scan sonar together with bathymetry and to receive detail information
for the sea bottom on the territory of the studied areas;
− To be checked, discovered and located new potential objects/locations potentially
interesting from archaeological point of view;
− To receive detail information for the underwater geological structures in order to be
complete and made more clear the picture for the development of the cost line along the
time;
The survey has been lunched with the support of the Ministry of the Culture Bulgaria.
A bathymetry and side scans have been conducted simultaneously using a boat along
planed in advance tracks in the studied areas.
The covered from the survey areas are:
− Sozopol North Bay and the area
between st. Kirik and st. Ivan
− Kiten area starting from the cape of
Primorsko from North, to bay of Oasis on
south side.
− Ahtopol North Bay
− Sinemorets south bay to “Silistar” bay
− The tracks between Ahtopol - Sinemorets
– Silistar
For the time of the survey have been
covered areas of over 27 sq. km. The
received side scan tracks are over 260 km
Fig. 01. Covered areas.
in more than 150 lines.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Area
Number of profiles
Length of the profiles
Area measured
Kiten
79
182,7
17.50
Ahtopol
26
13,0
2,60
Ahtopol - Sinemorets
4
22.5
3.50
Sinemorec South
31
40.0
3.05
Silistar
11
11.0
0.51
268.20 km
27.16 km2
Total:
Used equipment:
The used equipment for the survey has been:
- Bathymetry has been made with BBT-Flamingo echo sounder with integrated DGPS
system.
- Side scanning sonar StarFish 450H hull-mounted seabed imaging system for sea bed
scanning.
- For coordinate tracking system has been used Trimble DGPS system. The signal from
the DGSP has been split for precise online navigation of the boat and to coordinate the
side scan records.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Fig. 02. Block diagram of the equipment - connections.
Fig. 03. Block diagram of the data flow.
Used methodology for the measurements:
After several tests and considering the
tasks and the specific of the areas the
surveys have been conducted along in
advance planed tracks, usually in
perpendicular direction to the shore. In
major cases the tracks have been
made along east-west direction or
opposite.
Fig. 04. Side scan lines – Kiten – Primorsko area
The used distance between the tracks has been 80 meters to guarantee coverage of the
side scans from two tracks in the range of 50% to 70%. This methodology allows objects in
the middle zone between the tracks to be seen in the sonograms from two sides.
Along the shore, in shallow waters the surveys have been conducted in free tracks
depending from the situation, but closely to the shore.
The tracks have been with length until 25-30 m deepness has bean reached as in several
cases as control has been reached deepness of 40-45 m.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Along the free boat tracks to the destinations have been collected records as well in order
to be used as additional information and as control measurements.
Received results bathymetry:
The processing of the data is still ongoing but preliminary results are received.
Based on the received data from the echo sounder Flaming BBT preliminary bathymetrical
maps are created. The maps are available in WGS84 coordinate system or coordinate
system 1970.
The results are available as greed and data files, JPG or GeoTIFF files and KMZ files for
Google Earth.
Fig. 05. Bathymetrical map Kiten area: bay Primorsko south to “Oasis” bay.
Fig. 05A. Bathymetrical data for Kiten area printed in 3D shape.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Fig. 06. Bathymetrical map of Ahtopol - North bay.
Fig. 07. Bathymetrical map of the areas: Sinemorets south and “Silistar” bay.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Received results from side scans:
For all areas preliminary mosaics of images at the tracks are created. The results are
available in form of GeoTIFF or KMZ to be used with Google Earth program.
From the first overview of the sonograms have been selected over 700 potential sides or
individual objects on the sea bottom to be checked underwater. The main used criteria for
the selection are:
-
Objects which does not fit in the context of the exterior or present some logic of the
positioning like follow in aligned order or similar.
-
Objects which have specific shape or have been received extremely powerful echo
signal.
It is upcoming task the list and the information to be precisely evaluated in a short list with
potentially most interesting objects or areas from archaeological point of view, but even
now it is clear that there are several potentially very interesting locations which will be
checked with underwater surveys.
Fig. 08 Arch object on the sea bottom – the structure looks like it is constructed from
separate stones and does not fit the structure of surrounding rocks.
Centre of Underwater archaeology Sozopol
K. Velkovsky
Geophysical Prospecting and Underwater Archaeology Bathymetric and Side Scan
Sonar Surveys Sozopol – Sinemorets, September - October 2013
Fig. 09 Object with rectangular shape in the sand lie 6 m deep on the sea bottom.
Fig. 10. Arch object, pin 07, 4-5 m deep. The shape is similar to board of ship. The size of
the object is around 14 m length.
The post processing is currently ongoing and new results will be available.
Centre of Underwater archaeology Sozopol
K. Velkovsky