Formation and Plate Tectonics of Lake Bled, Slovenia

Lake Bled features Slovenia's only naturally occurring island. Lake Bled is set within a tectonic basin, which was created around 15,000 years ago [1]. After the last ice age, the Bohinj Glacier melted and flooded the basin, forming both Lake Bled and Lake Bohinj [2]. Bled Island, set in the middle of Lake Bled, was formed through erosion and weathering.

Lake Bled
From: https://www.lonelyplanet.com/a/slovenia/lake-bled/pois/sights/490156/places/360712

The basin was formed due to the tectonic uplifting of the Alps. The Alps mark the point of intersection between two converging tectonic plates; the African and Eurasian plates [3]. The Julian Alps are the portion of the Alps adjacent to Slovenia, acting as the country's northwestern border. Mount Triglav is the highest peak in this region of the alps, at 9,396 feet (~2864 meters).

Map of Peak Elevations
From: http://viewfinderpanoramas.org/prominence.html

Mount Triglav (Slovenia's Highest Peak)
From: http://www.traininginparadise.eu/wp-content/uploads/Mount-Triglav-the-North-wall-foto-Dan-Bri%C5%A1ki.jpg

The size of the Mount Triglav (just northwest of Lake Bled) is due to the convergence of the the African plate into the Eurasian plate, which took place 34 to 23 million years ago [4]. Although the formation of the Alps was a very ancient process as far as geological time is concerned, tectonic shifting between these two plates still affects the region today. For instance, there have been 25,000 earthquakes recorded in the last 10 years in Slovenia, and the country is considered "moderately vulnerable." Of the 25,000 recorded, about sixty have been dubbed "devastating" [5]. The map below details the different intensities of seismic activity affecting the country. Notice that blue colored area in the northeast (not the one on the border, but the one further inland) is almost directly over the Lake Bled area, making Bled very vulnerable to seismic activity. This makes a lot of sense, given that the region is set within the tectonic basin created by the convergence boundary between the African and Eurasian plates.

Map of Seismic Intensities

From: http://www.arso.gov.si/en/about%20the%20agency/ARSO_publikacija_ang.pdf (page 14)

[1] https://lakebledslovenia.com/
[2] http://www.slovenia.info/?jezero=190

[3] https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/01034.pdf

[4] http://quatr.us/geology/platetectonics/alps.htm

[5] http://www.sloveniatimes.com/120-years-since-earthquake-that-redefined-ljubljana

Other Sources Referenced http://www.blejski-grad.si/en/permanent-exhibition-by-national-museum