The objective in this experimental programme was to monitor microseismic activity at field scale in the same way that acoustic emission (AE) are monitored at sample scale, noting that the temporal variation of the AE level (or cumulated level) appears to be related to a variation of temporal stress and strain within the sample. We expected to show how the temporal variation of microseismic activity is related to the variation of temporal stress and strain in the rocks around and above the cavity. The aim was neither to characterize each kind of specific event nor to localize their source. We wanted to monitor the collapse as a continuous global event and eventually to focus on recorded features which may precede the collapse.