Measurement of Surface Displacement caused by underground nuclear Explosions by Differential SAR Interferometry

Differential synthetic aperture radar Interferometry (DInSAR) has
 nowadays become an important means for measuring and monitoring of
 surface displacements of various types. This paper focuses on investigating
 the capability of this technique for detection and characterization
 of past underground nuclear explosions at the Nevada Test Site (NTS),
 especially the synergy with
 
 seismic data. By this analysis large scale surface subsidence phenomena
 were revealed, which were either related to the detonation itself
 or post-event deformation. Data of different kinds, namely satellite
 data from both ERS 1 and 2, external DEM and seismic sources etc.,
 have been used for interferogram processing and interpretation. Because
 of the date limitation by the first acquired data from NTS, only
 few test events could be studied coseismically (i.e. from SAR data
 covering the period before and after the detonation); in the other
 cases investigations were restricted to postseismic deformation,
 i.e. restricted to post-event SAR data. The analysis was not limited
 to determination of the center of gravity of the subsidence crater,
 but also shape and depth of the deformation pattern were extracted.
 Theoretically, the amount of deformation could be measured with millimeter
 accuracy. But in realty, many other error sources must be taken into
 account, such as atmospheric effects, temporal decorrelation, and
 noise. Although this accuracy limit is therefore hard to realize
 in practice, the achieved precision usually outperforms other remote
 sensing techniques. This work has been carried out in part within
 the framework of the Global Monitoring for Security and Stability
 (GMOSS) Network
 
 of Excellence initiated by the European Commission.