1. Meeting of Young Scientist
BALATONFŐ LINE IN ULTRAHIGH-RESOLUTION: A NEOTECTONIC FAULT ZONE UNDER LAKE BALATON
Ferenc Visnovitz
Doctoral School of Environmental Sciences
Eotvos Lorand University
Budapest, Hungary
Meeting of Young Scientist
Békéscsaba
5th April , 2013

2. THE STUDY AREA:
LAKE BALATON 2
Székely, B. & Molnár, G. 2008

3. Principle of single channel water seismic imaging
WATER SEISMIC INVESTIGATIONS
IN THE AREA LAKE BALATON
Tóth et al. 2010
Single channel surveys:
Instrument: SEISTEC™
Source: boomer
Resolution: 0.1 m
Penetration: 5-40 m
Positioning: DGPS
Multichannel surveys:
Instrument: Streamer
Source: Air-gun
Resolution: 1-10 m
Penetration: m
Positioning: DGPS
Principle of single channel water seismic imaging
Reflections of acoustic waves are dermined by acoustic impedance contrasts 3

4. MAIN STRATIGRAPHIC UNITS IN SINGLE CHANNEL SEISMIC SECTIONS
(vertical exaggeration: x50)
The typically observed stratigrapic units under Lake Balaton:
horizontally stratified mud (mostly Holocene ~ 0 to15 kyr)
cross-bedded Pleistocene fluvial sediments
Pannonian deposits: faulted and folded (!) 4

5. about 1300 km single channel about 500 km multichannel profiles
AVAILABLE WATER SESIMIC PROFILES
about 1300 km single channel
&
about 500 km multichannel profiles 5

6. MAXIMUM HORIZONTAL STRESS ORIENTATIONS IN THE TRANSDANUBIA
Northern part (TDR): East-West oriented maximal horizontal stress
Southern part (Somogy ):
North-South oriented maximal horizontal stress
Balaton: transition zone? 6
Bada et al 2010

7. (BIDDLE & CHRISTIE-BLICK 1985)
GENERAL MODEL OF A LEFT LATERAL SHEAR ZONE EXPECTED IN THE AREA
(BIDDLE & CHRISTIE-BLICK 1985)
Modified after Biddle & Christie- Blick 1985 7

8. EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 1
EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 1. (SIÓFOK BASIN) 8

9. EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 2
EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 2. (SIÓFOK BASIN) 9

10. EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 3
EXAMPLE TO ILLUSTRATE NATURE OF FAULT UNDER LAKE BALATON 3. (SZEMES BASIN) 10

11. Fault indication map for the Eastern half of Lake Balaton (2013)
THE MAP VIEW OF FAULTS IDENTIFIED ON SEISMIC PROFILES
Fault indication map for the Eastern half of Lake Balaton (2013) 11

12. NEW RESULTS:
INTERPRETED FAULTS IN THE AREA OF THE SIÓFOK AND SZEMES BASIN 12

13. OVERVIEW OF THE MAIN DISPLACEMENT ZONES BASED ON INTERPRETED FAULTS AND THEIR ORIENTAION IN THE RECENT STRESS FIELD 13

14. SUGGESTED LEFT LATERAL ZONES WITH DISPLACEMENT DUPLEXES14

15. SUMMARY AND CONCLUSIONS
As consenquence of the recent stress field (with NE-SW oriented maximal princilpal stress) a left lateral strike slip zone formed in the area of Lake Balaton that manifested in faults almost parallel to the lake’s longitudinal axis.
Left lateral displacement zones are joining in the deeper part of the Balatonian basins where we observed strongly deformed structural blocks (tectonic displacement duplexes).
Orientation of en-echelon folds also confirm strike-slip nature of the fault systems (not presented here).
Our conclusion is that formation of the lake is not a result of a trench collapse mechaisms. „Prebalatonian” basins have developed in a zone weakened by strike slip tectonics where deflation and fluvial erosion could create deeper depressions. 15

16. Thank you for your kind attention!
Acknowledgement
New seismic surveys ( ) were supported by
NK83400 OTKA fund.
Seismic sections have been recorded in cooperation with Geomega. Measurements were helped by students of Eotvos University.
Special thanks to Attila Balázs for his help in seismic processing.
Thanks for Association of Hungarian Geophysicists for financing conference fees.
And finally…
Thank you for your kind attention!
References:
BADA G., SZAFIÁN P., VINCZE O., TÓTH T., FODOR L., SPIESS, V. & HORVÁTH F Neotektonikai viszonyok a Balaton keleti medencéjében és tágabb környezetében nagyfelbontású szeizmikus mérések alapján In: Földtani Közlöny, 140/4,
BIDDLE, K.T., CHRISTIE-BLICK, N Glossary (strike-slip deformation, basin formation and sedimentation). In: Biddle, K.T., Christie-Blick, N. (eds.): Strike-Slip Deformation, Basin Formation and Deformation. - Society of Economic Paleontologists and Mineralogists, Special Publication 37, , Tulsa, Oklahoma.
SACCHI, M Late Miocene evolution of the Western Pannonian basin, Hungary. In: Doktori (PhD) értekezés, ELTE TTK Geofizikai Tanszék, Budapest.
SZÉKELY, B. & MOLNÁR, G Do the post-Miocene volcanic features really mark a single paleoaltitude in the Transdanubian Range (Pannonian basin)? In: Geophysical Research Abstracts, 10: ISSN
TÓTH ZS., TÓTH T., SZAFIÁN P., HORVÁTH A., HÁMORI Z., DOMBRÁDI E., FEKETE N., SPIESS V. & HORVÁTH F Szeizmikus kutatások a Balatonon In: Földtani Közlöny 140/4,
VISNOVTZ F ÉS A BALATONI SZEIZMIKUS KUTATÓCSOPORT Késő-miocén üledékrétegek szeizmikus kutatása a Balaton középső medencéjében In: Környezettudományi Doktori Iskolák konferenciája kiadvány, ISBN , p 16