Title: Characteristics of infrasound signals from North Korean underground nuclear explosions on 2016 January 6 and September 9

Abstract

This study investigates infrasound signals from North Korean underground nuclear explosions on 2016 January 6 at 01:30:01 UTC (UNEJ16) and on 2016 September 9 at 00:30:01 UTC (UNES16). Infrasound observations from eight, seismo-acoustic arrays at distances of 300–600 km from the explosions and aligned approximately east–west across South Korea are used in the analysis. Progressive multichannel correlation was used followed by analyst review to identify the infrasound arrivals with estimates of azimuth, phase velocity, celerity, F-statistic, signal-to-noise ratio, correlation and signal duration. These observations are compared with model predictions of travel path, ray turning height and relative amplitudes, using Ground-to-Space atmospheric specifications at the time of each explosion. Stratospheric conditions at the time of the UNEJ16 are favourable to the Korean arrays when all arrays detected infrasound signals, while the few detections for UNES16 are consistent with unfavourable stratospheric winds and reduced amplitude thermospheric arrivals. Infrasound locations of the explosions were estimated using the Bayesian Infrasonic Source Location method (BISL), with wind-corrected backazimuth estimates based on the ray tracing calculations. Adding wind corrections to BISL resulted in infrasound locations up to 50 per cent closer to the seismic epicentre over uncorrected locations. The UNES16 infrasound location estimate using atmospheric correctionsmore » had larger differences (~67 km difference from seismic location) than the UNEJ16 location (~11 km difference from seismic location) as a result of the reduced number of observations and poor azimuth coverage for UNES16. Based on stratospheric phases recorded at six arrays and the empirical yield-scaling relations, wind corrected amplitudes from UNEJ16 lead to equivalent infrasound source energy estimates between 0.9 and 16.1 tons of TNT detonated in the atmosphere with an average of 6.4 tons and a standard deviation of 4.6 tons.« less

Authors:

Park, Junghyun ^[1]; Che, Il-Young  ^[2];

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Stump, Brian ^[1]; Hayward, Chris ^[1]; Dannemann, Fransiska ^[1]; Jeong, SeongJu ^[1]; Kwong, Kevin ^[1]; McComas, Sarah ^[1]; Oldham, Harrison R. ^[1]; Scales, Monique M. ^[1]; Wright, Vanshan ^[1]

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+ Show Author Affiliations

1. Southern Methodist Univ., Dallas, TX (United States). Roy Huffington Dept. of Earth Sciences
2. Korea Inst. of Geoscience and Mineral Resources, Daejeon (Korea, Republic of)

Publication Date:

Fri Jun 22 00:00:00 EDT 2018

Research Org.:

Southern Methodist Univ., Dallas, TX (United States); Korea Inst. of Geoscience and Mineral Resources, Daejeon (Korea, Republic of)

Sponsoring Org.:

USDOE; Ministry of Science, ICT and Future Planning (MSIP) of Korea

OSTI Identifier:

1459833

Report Number(s):

LA-UR-18-21282
Journal ID: ISSN 0956-540X; TRN: US1901809

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Geophysical Journal International

Additional Journal Information:

Journal Volume: 214; Journal Issue: 3; Journal ID: ISSN 0956-540X

Publisher:

Oxford University Press

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; acoustic properties; earthquake monitoring and test-ban treaty verification; wave propagation