초록

1. 북한핵실험 및 구소련, 미국 핵실험 파형 비교
2. 과거 핵실험 관련 연구
3. 핵실험 진원 모델 연구
4. 인공 지진 모서리 주파수, 규모-발파량 상관 관계 연구
5. 인공 발파와 자연지진과의 차이점 고찰
6. 핵실험 판정 기법 고찰
7. 발파량-규모값 관계
8. 공중음파 자료 분석 기법
9. 인공 지진으로부터 발생한 P파 S파 특성
10. 인공 지진 발생시 S파 발생원리 고찰

Abstract ▼

Two North Korean underground nuclear explosion (UNE) tests were conducted on 9 October 2006 and 25 May 2009. Both UNEs are well observed by dense regional seismic networks. Many regional seismic stations recorded the events. Regional source-spectral parameters and path parameters could be estimated.

Two North Korean underground nuclear explosion (UNE) tests were conducted on 9 October 2006 and 25 May 2009. Both UNEs are well observed by dense regional seismic networks. Many regional seismic stations recorded the events. Regional source-spectral parameters and path parameters could be estimated. The comer frequencies and overshoot parameters of P phases (Pn, Pg) are higher than those of S phases (Sn, Lg). The comer frequencies of regional phases from the 2009 UNE are lower than those from the 2006 UNE, except Lg. The overshoot parameters of S phases from the 2009 UNE are higher than those from the 2006 UNE. Spectral amplitude ratios of regional phases between the two UNEs are not close to the ratio of scalar isotropic moments from long-period waveform inversions. On the other hand, average Pn source-spectral ratios between the two UNEs is ~5, which is close to the scalar isotropic moment ratio. The Pn energy increases linearly with event strength, while the other phases do not increase as much as the event-strength increment. It is observed that P/S source spectra are useful for discrimination of UNEs from earthquakes.
Regional and teleseismic waveforms of underground nuclear explosions (UNEs) at the Balapan and the Nevada test sites are analyzed to understand the nature of shear waves excitation. The phase composition of wavefields in the source and receiver regions could be examined using a source array frequency wave number analysis and polarization analyses. It is observed that regional mantle lid shear waves, Sn, often develop strongly. On the other hand, observed teleseismic shear waves from UNEs are much weaker than those from earthquakes. Source array analyses of the shear waves from UNEs display coherent energy that is polarized in a certain azimuthal direction. The observation of coherent shear energy in different UNEs suggests that the shear energy is excited in a consistent manner at every UNE. We constrain the dominant shear wave excitation mechanism from the observed shear wave features. The observations appear to be consistent with the tectonic release model with conical rock cracking.
The source array analysis shows that the polarization directions of shear waves vary with azimuths. This observation suggests azimuthally anisotropic radiation of shear energy, which may be a result of multiple shear wave excitation sources. We find that considerable amount of shear energy is observed from regional UNE records. The strength of regional shear energy appears to vary with station, which may be a result of combined effects of receiversite geology, anisotropy along ray paths and inhomogeneous radiation from the sources. On the other hand, we find significantly low shear energy in teleseismic ONE records, implying weak radiation of shear energy at low take-off angles.
The observational features of regional and teleseismic records are examined with respect to various shear wave excitation mechanisms, which include S*, tectonic release (rock cracking), Rg to S scattering, and spall. Among various shear-wave excitation mechanisms proposed, tectonic release (Wallace et al., 1985), spalling (Day and McLaughlin, 1991), and rock cracking (Masse, 1981) may be plausible. The explosional source features, that is, strong compressional energy and strong spectral overshooting, allow us to use the P=S spectral amplitude ratios to discriminate between nuclear explosions and earthquakes. Such discrimination appears to be effective in the frequency range of 1 - 8 Hz.
Seven infrasound stations are operated by KIGAM. The infrasound stations observed the 2009 North Korean UNE. The infrasound records has limitation in high- precision locationing of event. However, the infrasound observation supports detonation of explosion. The applicability of the infrasound monitoring was investigated. Also, the array responses of infrasound monitoring system was examined.

목차 Contents

• 표지 ...1
• 제출문 ...2
• 보고서 요약서 ...3
• 요약문 ...4
• SUMMARY ...8
• CONTENTS ...10
• 목차 ...11
• 제1장 연구개발과제의 개요 ...12
• 제2장 국내외 기술개발 현황 ...13
• 제3장 연구개발수행 내용 및 결과 ...14
• 제1절 연구 요약 ...14
• 제2절 인공지진 판별 기법 (overview) ...16
• 제3절 한반도 지각구조 ...27
• 제4절 북한 핵실험 지진파 분석 ...39
• 제5절 해외 핵실험 자료 분석 ...59
• 제6절 북한 핵실험 판별 ...95
• 제7절 공중음파 분석 기법 ...112
• 제4장 목표달성도 및 관련분야에의 기여도 ...117
• 제5장 연구개발결과의 활용계획 ...117
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ...118
• 제7장 참고문헌 ...119