Marine Geophysics and Hydroacoustics

Lake Ohrid

Summary

Lake Ohrid, located on the Balkan Peninsula within the Dinaride-Hellenide-Albanide mountain chain (Macedonia/Albania) is probably the oldest, continuously existing lake in Europe (2-5 Ma).

Surveys

Multidisciplinary including multichannel seismics, sediment echosounder, and coring at Lake Ohrid prove that it is an important archive to study the sedimentary and tectonic evolution of a graben system over a long time period. Within the frame of the International Continental Drilling Program (ICDP) a successful deep drilling campaign was carried out in spring 2013 with more than 2000 m of sediment cores at four sites. more Downhole logging was realized at each site after coring, enabling us to integrate geophysical and sedimentological data into seismic cross sections in order to get a profound knowledge of climatic and environmental changes in the catchment area.

bathymetric map of Lake Ohrid

 

 

 

 

 

 

 

 

 

 

 

 

Deep Drilling Campaign SCOPSCO (ICDP)

The longest record (~569 m, site DEEP), recovered in the central part of lake Ohrid likely covers the entire lacustrine succession within Lake Ohrid Basin including several Interglacial and Glacial cycles. Sedimentological analyses are still ongoing; however, the upper 260 m of the DEEP reflecting the time period between Mid-Pleistocene Transition to present. An integration of borehole geophysical data into surface seismic lines shows that sediments, within the central part of Lake Ohrid, were deposited in a deep water environment over the last 600 ka. For the uppermost sediment cover, about 50 m of penetration, a very high resolution sediment echosounder data set allows us to identify major tephra layers and track them through the entire deep basin. Furthermore, a vertical seismic profile was carried out at site DEEP resulting in a conversion from two-way-travel-time into sediment depth. One major outcome is a corridor stack of the upgoing wave that clearly shows several reflectors linked to changes of sediment properties of cores and hence environmental and climate changes in the surrounding area of Lake Ohrid Basin.map

Several changes from Glacial to Interglacial, and vice versa, have been observed in the seismic data. Using a preliminary age model for interpreting physical parameters such as natural gamma ray, magnetic susceptibility, and sonic velocity shed light on causes and timing of additional reflectors at the site where the DEEP hole was cored in 2013. A grid of surface seismic lines enables us to expand this to the entire central basin and to reconstruct the sedimentary history of Lake Ohrid suggesting that the deep basin was in a rather stable condition with a water depth greater than a 100m.

Mass Wasting and Tsunami Model

The Udenisht slide complex in the southwestern part of the lake is by far the largest mass failure event within the lake. The slide covers an area of about 27 km², has an average thickness of 30 to 40 m, and an estimated volume of 0.11 km³. The general morphology of the Udenisht slide is characterized by a rough topography with a rupture surface within the up-slope region and an area of displaced material that spreads up to 10 km into the central basin. Further evidence of the slide includes sidewalls with heights of 25 m within an area where the rupture occurred as well as massive blocks with diameters of 150 m within the depositional area. First age estimations suggest the Udenisht slide is less than 2000 years old.

The volume of the Udenisht slide is well within the range of landslide volumes that are known to have triggered tsunamis. However, because the slide event was retrogressive with three small sub-events and because the deposits are heavily deformed the waves associated with the Udenisht slide were most likely small. In contrast, smaller slides north of the Udenisht slide complex have a higher tsunamigenic potential because the sliding process is similar to a rotational slump.

Tsunami model

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Person to contact: Katja Lindhorst and Sebastian Kastel

Scientific expeditions and drilling campaign:

  • 2007 and 2008: Multichannel seismic, sediment echosounder and sidescan sonar
  • 2009: BLOSSOM: Bathymetry at Lake Ohrid for Subaquatic Slide Overview Mapping (Mini-Proposal ISOS PhD), Bathymetric and sediment echosounder survey
  • 2013: SCOPSCO ICDP deep drilling campaign April 1st - June 3rd,

 

Related Publications:

  • Wagner, B., Wilke, T., Francke, A., Albrecht, C., Baumgarten, H., Bertini, A., Combourieu-Nebout, N., Cvetkoska, A., D'Addabbo, M., Donders, T.H., Föller, K., Giaccio, B., Grazhdani, A., Hauffe, T., Holtvoeth, J., Joannin, S., Jovanovska, E., Just, J., Kouli, K., Koutsodendris, A., Krastel, S., Lacey, J.H., Leicher, N., Leng, M.J., Levkov, Z., Lindhorst, K., et al. , 2017. The environmental and evolutionary history of Lake Ohrid (FYROM/Albania): interim results from the SCOPSCO deep drilling project. Biogeosciences 14, 2033-2054.

  • Lindhorst, K., Krastel, S., Baumgarten, H., 2016. Mass Wasting History Within Lake Ohrid Basin (Albania/Macedonia) Over the Last 600 ka, in: Lamarche, G., Mountjoy, J., Bull, S., Hubble, T., Krastel, S., Lane, E., Micallef, A., Moscardelli, L., Mueller, C., Pecher, I., Woelz, S. (Eds.), Submarine Mass Movements and their Consequences: 7th International Symposium. Springer International Publishing, Cham, pp. 291-300.

  • Lindhorst, K., Krastel, S., Reicherter, K., Stipp, M., Wagner, B., Schwenk, T., 2015. Tectonic and Sedimentary Evolution of Lake Ohrid (Albania/Macedonia). Basin Research 27, 84-101.

  • Wagner, B., Wilke, T., Krastel, S., Zanchetta, G., Sulpizio, R., Reicherter, K., Leng, M., Grazhdani, A., Trajanovski, S., Francke, A., Lindhorst, K., et al. 2014. The SCOPSCO drilling project recovers more than 1.2 million years of history from Lake Ohrid. Scientific Drilling 17, 19-29.

  • Lindhorst, K., Krastel, S., Papenberg, C., Heidarzadeh, M., 2014. Modeling Submarine Landslide-Generated Waves in Lake Ohrid, Macedonia/Albania, Submarine Mass Movements and Their Consequences. Springer, pp. 497-506.

  • Wagner, B., Francke, A., Sulpizio, R., Zanchetta, G., Lindhorst, K., Krastel, S., Vogel, H., Daut, G., Grazhdani, A., Lushaj, B., 2012. Seismic and sedimentological evidence of an early 6th century AD earthquake at Lake Ohrid (Macedonia/Albania). Climate of the Past 8, 2069-2078.

  • Lindhorst, K., Gruen, M., Krastel, S., Schwenk, T., 2012. Hydroacoustic Analysis of Mass Wasting Deposits in Lake Ohrid (Former Yugoslavian Republic of Macedonia/Albania), in: Yamada, Y., Kiichiro Kawamura, Ken Ikehara, Yujiro Ogawa, Roger Urgeles, David Mosher, Jason Chaytor, Strasser, M. (Eds.), Submarine Mass Movements and Their Consequences. Springer Netherlands, pp. 245-253.

  • Reicherter, K., Hoffmann, N., Lindhorst, K., Krastel, S., Fernandez-Steeger, T., Grutzner, C., Wiatr, T., 2011. Active basins and neotectonics: morphotectonics of the Lake Ohrid Basin (FYROM and Albania). Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 162, 217-234.

  • Lindhorst, K., Vogel, H., Krastel, S., Wagner, B., Hilgers, A., Zander, A., Schwenk, T., Wessels, M., Daut, G., 2010. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores. Biogeosciences 7, 3531-3548.