Exploring the potential of seismic sensors in monitoring slow moving landslides in Lower Austria

Landslides pose a significant threat to settlements, infrastructure and communities globally. In order to mitigate the potential impact and damages caused by these phenomena, various approaches and methodologies have been developed and implemented. Among these, the continuous monitoring of slope instabilities is crucial for understanding landslide dynamics and gaining information in predisposing and triggering factors. In this context, the use of passive seismic sensors has emerged as a powerful tool for monitoring, as they can detect subtle transient slope mechanical and hydrological changes as well as unpredictable episodes of signal emission associated with slope deformation processes. By continuously recording such microseismic activity, seismometers can provide data on landslide movements, offering valuable insights into the state of activity and allowing a better understanding of the relationships between the driving mechanisms.

This study provides a preliminary attempt on the investigation of slow-moving processes occurring in the region of Lower Austria, which is known to be highly prone to landslides due to its complex geological characteristics. The lithological transition between the Flysch and Klippen Unit formations consists predominantly of mechanically weak components, such as intercalated limestones and marlstones to claystone and deeply weathered materials. Combined with hydrological factors, changes in land use, and anthropogenic influences, these predisposing conditions contribute to the region's susceptibility to slope instability.

In this work, we present the results from an ongoing monitoring conducted across three well established landslide observatories in this region, which have been co-instrumented with a total of 26 geophones to monitor landslide activity. The deployed compact seismic stations consist of geophones, installed at 25 cm depth in dug pits, and a DataCube data logger recording ground velocity values at 200 Hz sampling frequency. This setup is powered by a 55Ah 9V battery and periodically visited to extract data and check the station status. Here, we evaluate and discuss the seismic expression of external drivers, co-registered slope deformation and spatio-temporal patterns of slope activity. In addition, taking advantage of the sensors included in the monitoring network installed in each site (e.g. inclinometers, piezometers), we examine the possibility of analysing the relationship with possible drivers and reactions on nested temporal scales. The findings of this work contribute to advancing the application of passive seismic monitoring technologies in landslide research, particularly in the context of slow-moving landslides.