INSAR observations of the DPRK event series

Interferometric synthetic aperture radar (INSAR) data have revealed signals associated with the recent DPRK events in 2016 and 2017. These signals include decorrelation and indications of subsidence. Both standard phase differences and amplitude offsets are calculated. We show results of INSAR analysis as conducted using C and L band data and investigate the causes of the decorrelation (e.g. subsidence, landslide, or spall) and compare the observed signal with numerical models of deformation and seismic observations. A time series approach is applied to constrain post-event deformation at the weeks to months' timescale. We compare the INSAR observations of the DPRK tests with previous observations of events at other source regions using ERS archive data, which revealed a variety of post-seismic signatures. The signatures are evaluated with respect to the known geology and causes, including long-term surface relaxation and possible groundwater/thermal effects. Particular focus is on the sites on Pahute and Rainier Mesa, which displayed long-term subsidence signals that extended for several years after the explosions. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC