Monitoring peatlands with novel geophysical methods

Understanding the subsurface structure and dynamics of peatlands, is key to understanding their role in ecosystem services and processes. Many existing methods are limited to capturing information about small surface areas, over limited time periods, and are labour intensive. Geophysical approaches have the potential to overcome some of these limitations.

We present the preliminary results of a project aiming to develop novel geophysical methods to image peat bogs in 3-dimensions and to monitor peatland health over time. We use seismic nodes for low-cost, non-invasive, continuous monitoring. A network of seven nodes has so far been deployed on an un-restored upland peatland setting in North East Scotland, with in situ waterloggers already established. Using ambient background noise (‘seismic interferometry’), we investigate how the seismic velocity changes over time as a proxy for groundwater changes, an important measure of peatland health. We further conduct an active seismic survey to assess peat thickness by combining surface wave dispersion with the natural ground resonance frequency, obtaining peat thicknesses of ~3.5m, comparable to depths measured using conventional peat probing. We also investigate the utility of other geophysical techniques to image peat structure and saturation, including Ground Penetrating Radar and Electrical Resistivity Tomography.