Observed Surface Disturbances Associated with the DPRK’s 3 September 2017 Underground Nuclear Test

Yield Estimates for the Six North Korean Nuclear Tests From TeleseismicPWave Modeling and Intercorrelation ofPandPnRecordings

“…Precise relative locations for the six explosions, with uncertainties on the order of a few hundred meters, have been determined by numerous seismic differential arrival time studies (e.g., Carluccio et al, ; Gibbons et al, , ; He et al, ; Myers et al, ; Murphy et al, ; Selby, ; Wang et al, ; Wen & Long, ; Yao et al, ; Zhang & Wen, ; Zhao et al, ; Zhao, Xie, He, et al, ). Absolute locations are much more difficult to resolve, and various strategies have been used to place the suite of precise relative locations in absolute position with respect to the source region topography, locations of tunnel portals, and/or deformation features on the surface inferred from InSAR or satellite photography (e.g., Murphy et al, ; Myers et al, ; Pabian & Coblentz, ; Pabian & Hecker, ; Patton & Pabian, ; Wei, ), with recent results having less than ~0.5‐km variations. The absence of collapse craters for all events complicates the absolute location process and indicates that burial depths for most events significantly exceed what is required for containment.…”

Seismic Spectral Ratios Between North Korean Nuclear Tests: Implications for Their Seismic Sources

“…While the apparent DOB estimations for NKT2009–2016S are generally consistent with the height of Mount Mantap, the apparent DOB of NKT2017 is greater than the mountain's maximum height (~800 m) with respect to the tunnel's adit in which the tests were conducted. This result is reasonable for NKT2017 is likely detonated under the summit of Mount Mantap (e.g., Myers et al, ; Pabian & Coblentz, ). As strong surface disturbances caused by it have been observed, NKT2017's apparent DOB should be greater than its real DOB.…”

“…According to this absolute location result, the last five Korean nuclear tests were detonated in the so‐called North tunnel in Murphy et al () and were located within a small area under Mount Mantap of the Punggye‐ri nuclear test site with a diameter of less than 1 km. With respect to the tunnel entrance, the maximum height of the test mountain is approximately 800 m. And it is covered by granite‐like hard rock except for the uppermost 200 m which is covered by volcanic deposits (Coblentz & Pabian, ; Pabian & Coblentz, ).…”

“…Anyway, according to the definition of equation , the apparent Δ t pP value of 0.4 s is equivalent to an apparent DOB of about 830–1,060 m taking cos i P corresponding to Δ = 60 ∘ and assuming 4,000–5,000 m/s for in equation . For surface disturbances associated with nonlinear effects of pP reflection for NKT2017 were observed (e.g., Pabian & Coblentz, ), NKT2017's real DOB should be smaller than its apparent DOB, although it is difficult to quantify the bias between them due to the complicacy of the problem.…”

Exploratory Efforts to Constrain Geologic Material Properties from Remote Sensing Data: Joint Study (FY2020 Final Report)

“…During and following the completion of the Venture, a number of novel data analyses have been undertaken, including those that dive deep into ground-based physical observations and measurements, those that use remotely sensed information in more informed ways to assess activities at a site, and those that integrate multiple data modalities. Some recent, provocative research suggests that geomorphometry, or quantitative land surface analysis, can provide insight into both the strength and integrity of rock masses at test sites (Coblentz and Pabian, 2015;Pabian and Coblentz, 2018). However, these studies related topography only to broad geology type, and not quantitative mechanical properties.…”