Joint Land and Shallow-Marine Seismic Investigations of Landslide Processes in the Bay of Trondheim, Mid-Norway

The urban development of the city of Trondheim in the last century has extended onto the near-shore areas (Figure 1). In the last 15 years, land reclamation has been intensified for construction work and building activity. Historical landslides are known to have occurred along the shore (e.g., L’Heureux et al., 2007). Damages to coastal infrastructures and loss of life resulted from these events. In one case (1888) a devastating tsunami wave struck the shoreline (Figure 1). The combination of historical landslides and urbanization has increased the concerns about the stability of the near-shore slopes. Therefore, numerous geological, geophysical and geotechnical investigations were carried out in recent years to explore in detail the stratigraphy of the fjord-valley fill and to investigate the stability both on land and in the fjord. One of the purposes of this paper is to show the ability of the shear-wave seismic method to study fjord-valley sediments from paved areas. In addition, we demonstrate the exceptionial potential for correlation between land-seismic and shallow-marine seismic data sets.