Yield Estimate (230 kt) for a Mueller‐Murphy Model of the 3 September 2017, North Korean Nuclear Test (mbNEIC = 6.3) From Teleseismic Broadband P Waves Assuming Extensive Near‐Source Damage

Abstract

AbstractThe 3 September 2017 underground nuclear test (mbNEIC = 6.3) is the largest of six announced North Korean explosions. The event generated many P wave seismograms at global broadband seismic stations with good signal‐to‐noise ratio for periods less than ~5 s. Instrument deconvolution provides 435 stable broadband P wave ground displacement records in the period range 0.1 to 5.0 s. These are stacked in 26 azimuth/distance windows to average path and receiver effects. Waveform stacks and average amplitude of 4‐Hz ground displacements are modeled assuming a Mueller‐Murphy explosion source model for a granite source medium. Nonelastic pP delays consistent with burial depths in the mountainous source topography are considered, and explosion yield and an average constant‐Q attenuation operator are estimated by fitting the waveforms. For a source depth of 750 m in heavily damaged environment, the estimated yield = 230 ± 50 kt and t* = 0.78 ± 0.03 s.