High-resolution seismic surveys

High-resolution seismic data are acquired mostly with our Parasound system that is installed on the larger research vessels. The acoustic waves generated by this system do not penetrate deeper than roughly 100 meters into the sediment, depending on sediment type. Resolution, however, is high enough for a sound detection of the smaller-scale geometries and the nature of the uppermost sedimentary layers. 

In the Parasound profiles, we can for example recognize sediments that were deposited in an undisturbed manner over millenia. We can also identify if these well-layered undisturbed sediments are locally disturbed by sediment packages that derive from sliding. We can further detect head walls of such slides and investigate possible triggering mechanisms such as earthquakes or slope instabilities. 

Parasound profiles can also be used to identify areas where sediments were glacially overprinted. Deep icebergs and ice sheets plough the underlying sediment with their keels, leaving characteristical grooves in the seafloor morphology. Grounded ice sheets change the sediment's density by their weight, which is recognizable in the Parasound profiles.

Parasound combined with bathymetric data help to reconstruct the depositional history of the uppermost sedimentary layers.

Furthermore, Parasound data help us to identify the perfect spots to take sediment cores. These cores can then be dated and investigated for paleoclimate history.

For our projects in lakes we own a small, portable 3.5 kHz system that provides data similar to those acquired with the Parasound system.

Dr. Catalina Gebhardt