Client

Tiefbau Schaffhausen

Geological Office

Dr. von Moos AG

Services Provided

• Two-day measurement campaign with 143 passive seismic point measurements, combined with 4 active seismic profiles.
• Identification of additional collapse-prone areas around the existing doline using seismic vibrometry.
• Determination of the bedrock depth and exploration of additional unknown cavities using refraction seismics.

Project Description

Following the appearance of a sinkhole beneath an apiary in 2024, in close proximity to a bike route, it became necessary to assess the stability of the surrounding terrain. Since the area is crisscrossed by a former gypsum mine with numerous, yet only moderately documented, tunnels, Spektrum Geophysik AG was commissioned to conduct geophysical mapping. The aim of the investigation was to locate additional potential collapse sites and assess the hazard potential for the adjacent infrastructure.

Seismic vibrometry identified areas with significantly increased amplification on the side of the doline that faces away from the bike path, indicating a strong degradation of the rock. This was later confirmed by further collapses in the designated areas. In addition, refraction seismics along several active seismic profiles were used to determine the bedrock depth, while targeted exploration of unmapped tunnels did not provide clear indications of additional larger cavities or caverns.