Publikation

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Originalbeitrag (peer-reviewed)

Zeitschrift Geomorphology
Titel der Proceedings Geomorphology

Abstract

The history of Lake Kivu is strongly linked to the activity of the Virunga volcanoes. Subaerial and subaquatic volcanoes, in addition to lake-level changes, shape the subaquatic morphologic and structural features in Lake Kivu's Main Basin. Previous studies revealed that volcanic eruptions blocked the former outlet of the lake to the north in the late Pleistocene, which lead to a substantial rise in the lake level and subsequently the present-day thermohaline stratification. Additional studies have speculated that volcanic and seismic activity threaten to trigger a catastrophic release of the large amount of gases dissolved in the lake. A survey conducting bathymetric mapping and seismic profiling covered the volcanically active area of the Main Basin at a resolution unprecedented for Lake Kivu. New geomorphologic features on the lake floor can for the first time accurately describe related lakefloor processes. The late Pleistocene lowstand is observed at 425 m depth, and volcanic cones, tuff rings, and lava flows observed above this level indicate both subaerial and subaquatic volcanic activity during the Holocene. The geomorphologic analysis yields new implications on the geologic processes that have shaped Lake Kivu's basin, and the possibility of a lake overturn.
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