The Gradenbach mass movement (GMM) is an example of DGSD (deep-seated gravitational slope deformation) in crystalline rocks of the Eastern Alps (12.85°E, 47.00°N). The main body of the GMM covers an area of 1.7km 2 and its volume is about 120×10 6 m 3. A reconstruction of the deformation history yields a mean displacement of∼22m from 1962 to . In 1965 /66, 1975 , 2001 , and 2009 high sliding velocities, exceeding several meters per year, interrupt the quasi-stationary periods of slow movement (≤0.3m/year). Since 1999 the displacement of the main body of the GMM has been observed by GPS. Time series of extensometer readings, precipitation, snow cover water equivalent, water discharge, and hydrostatic water level observed in boreholes were re-processed and are presented in this paper. Continuous recording of seismic activity by a seismic monitoring network at the GMM began in the summer of 2006. Deformation has been monitored since 2007 by an embedded strain rosette based on fiber optics technology and a local conventional geodetic deformation network. The velocity of the GMM could be modeled to a large extent by a quantitative relation to hydro-meteorological data. During the phase of high sliding velocity in spring 2009, the seismic activity in the area increased significantly. Several types of seismic events were identified with some of them preceding the acceleration of the main body by about 6 weeks. The potential inherent in the Gradenbach Observatory data to supply early warning and hazard estimation is discussed.

Geological and geophysical investigations, as well as drilling have brought the quality of geotechnical prognosis for tunnels to a high standard. However, the remaining risk during tunnel construction is still considerable, especially in case of construction by a tunnel boring machine (TBM). Seismic imaging of faults and other geological features affecting the construction ahead of a tunnel face can supply valuable information to reduce this risk. These methods are based on Vertical Seismic Profiling (VSP) locating sources and receivers in the tunnel and generating seismic waves by small blasts or mechanical devices. A fundamental problem in the application of this method is that reflectors (fault zones, petrologic boundaries, or similar) are imaged at their intersection with the tunnel axis only in case they are orthogonal to this axis. Reflectors oriented obliquely to the tunnel axis may be imaged perfectly. However, they must be extrapolated to their intersection with the tunnel axis, thus imposing major uncertainties on prediction.Therefore it was decided to concentrate on Tunnel Seismic While Drilling (TSWD), an alternative method, which uses the vibrations produced by the cutting head of the TBM as seismic source. Continuous monitoring is possible by this method and the above mentioned problem may be overcome. Conventional seismic traces are extracted from the recordings by the use of a pilot signal recorded near the cutting head of the TBM. First results from a pilot study accompanying the construction of a gallery in the Gesäuse mountain range, Styria, Austria are presented. The bandwidth of the seismic signals is >200 Hz, a high signal to noise ratio is achieved, and excellent conventional seismic traces are extracted. Thus the most important component of the whole method has been realised successfully. Additional aspects of the method are discussed and an outlook to the continuation of the pilot study is given.

Rapidly-rising jökulhlaups, or glacial outburst floods, are a phenomenon with a high potential for damage. The initiation and propagation processes of a rapidly-rising jökulhlaup are still not fully understood. Seismic monitoring can contribute to an improved process understanding, but comprehensive long-term seismic monitoring campaigns capturing the dynamics of a rapidly-rising jökulhlaup have not been reported so far. To fill this gap, we installed a seismic network at the marginal, ice-dammed lake of the A.P. Olsen Ice Cap (APO) in NE-Greenland. Episodic outbursts from the lake cause flood waves in the Zackenberg river, characterized by a rapid discharge increase within a few hours. Our 6 months long seismic dataset comprises the whole fill-and-drain cycle of the ice-dammed lake in 2012 and includes one of the most destructive floods recorded so far for the Zackenberg river. Seismic event detection and localization reveals abundant surface crevassing and correlates with changes of the river discharge. Seismic interferometry suggests the existence of a thin basal sedimentary layer. We show that the ballistic part of the first surface waves can potentially be used to infer medium changes in both the ice body and the basal layer. Interpretation of time-lapse interferograms is challenged by a varying ambient noise source distribution.

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