Phase composition of regional seismic waves from underground nuclear explosions

Tae-Kyung Hong, Jiakang Xie

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The mechanism of regional shear wave excitation by underground nuclear explosions (UNE), a long-standing issue in nuclear seismology, is investigated by studying the phase composition of regional waves from clustered UNE. Regional seismic waves from 67 UNE at the Balapan test site of Kazakhstan, recorded at station Borovoye, are analyzed with a source array technique under the reciprocity theorem. This analysis allows one to obtain the phase velocity composition of the plane waves leaving the source region. Source locations and the original times are obtained from geodetic measurements, a scaling law between event magnitude and depth, and a calibrated Pn travel time curve. Between frequencies of 0.5 and 3.0 Hz the Pn slowness power spectra are concentrated at a phase velocity (vh) of 8.0 km/s. The expected Sn window contains two dominant phases: a scattered P wave with a vh of around 7.1 km/s and a mantle shear wave with a vh of 4.8 km/s. The Lg waves are coherent between 0.5 and 2.0 Hz, with a dominant vh of 4.2 km/s, which is typical in SmS-type waves. The Rg wave at frequencies between 0.5 and 0.8 Hz is dominantly composed of a coherent fundamental mode Rayleigh wave with a vh of 3.0 km/s. At higher frequencies (>0.8 Hz) this coherent Rayleigh wave is not observed in the Rg window because of attenuation during wave propagation. The slower vh of Rg and faster vh of Lg, at which the strong coherent peaks in slowness power spectra are observed, suggest that the dominant components of these two waves are different and they are originated differently in the source region. The proposed Rg-to-S scattering does not appear to be a dominant mechanism for Lg excitation in the Balapan test site. It is also found that the strength of shear waves contained in the expected Sn window varies with local geology much more than the strength of Lg does. Since the Sn is enriched in high-frequency (>1 Hz) content as compared to the Lg, this observation suggests that the local geology influences shear wave excitation at high frequencies more than at lower frequencies.

Original languageEnglish
Article numberB12302
Pages (from-to)1-11
Number of pages11
JournalJournal of Geophysical Research: Solid Earth
Volume110
Issue number12
DOIs
Publication statusPublished - 2005 Dec 4

Fingerprint

Underground explosions
underground explosions
Nuclear explosions
nuclear explosions
nuclear explosion
Seismic waves
seismic waves
Phase composition
seismic wave
S waves
S-wave
Shear waves
wave excitation
Rayleigh waves
phase velocity
Rayleigh wave
geology
power spectra
Phase velocity
Geology

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

@article{aa8111e9b6c14dac9b64ab526f12fdfb,
title = "Phase composition of regional seismic waves from underground nuclear explosions",
abstract = "The mechanism of regional shear wave excitation by underground nuclear explosions (UNE), a long-standing issue in nuclear seismology, is investigated by studying the phase composition of regional waves from clustered UNE. Regional seismic waves from 67 UNE at the Balapan test site of Kazakhstan, recorded at station Borovoye, are analyzed with a source array technique under the reciprocity theorem. This analysis allows one to obtain the phase velocity composition of the plane waves leaving the source region. Source locations and the original times are obtained from geodetic measurements, a scaling law between event magnitude and depth, and a calibrated Pn travel time curve. Between frequencies of 0.5 and 3.0 Hz the Pn slowness power spectra are concentrated at a phase velocity (vh) of 8.0 km/s. The expected Sn window contains two dominant phases: a scattered P wave with a vh of around 7.1 km/s and a mantle shear wave with a vh of 4.8 km/s. The Lg waves are coherent between 0.5 and 2.0 Hz, with a dominant vh of 4.2 km/s, which is typical in SmS-type waves. The Rg wave at frequencies between 0.5 and 0.8 Hz is dominantly composed of a coherent fundamental mode Rayleigh wave with a vh of 3.0 km/s. At higher frequencies (>0.8 Hz) this coherent Rayleigh wave is not observed in the Rg window because of attenuation during wave propagation. The slower vh of Rg and faster vh of Lg, at which the strong coherent peaks in slowness power spectra are observed, suggest that the dominant components of these two waves are different and they are originated differently in the source region. The proposed Rg-to-S scattering does not appear to be a dominant mechanism for Lg excitation in the Balapan test site. It is also found that the strength of shear waves contained in the expected Sn window varies with local geology much more than the strength of Lg does. Since the Sn is enriched in high-frequency (>1 Hz) content as compared to the Lg, this observation suggests that the local geology influences shear wave excitation at high frequencies more than at lower frequencies.",
author = "Tae-Kyung Hong and Jiakang Xie",
year = "2005",
month = "12",
day = "4",
doi = "10.1029/2005JB003753",
language = "English",
volume = "110",
pages = "1--11",
journal = "Journal of Geophysical Research: Solid Earth",
issn = "2169-9313",
publisher = "Wiley-Blackwell",
number = "12",

}

Phase composition of regional seismic waves from underground nuclear explosions. / Hong, Tae-Kyung; Xie, Jiakang.

In: Journal of Geophysical Research: Solid Earth, Vol. 110, No. 12, B12302, 04.12.2005, p. 1-11.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Phase composition of regional seismic waves from underground nuclear explosions

AU - Hong, Tae-Kyung

AU - Xie, Jiakang

PY - 2005/12/4

Y1 - 2005/12/4

N2 - The mechanism of regional shear wave excitation by underground nuclear explosions (UNE), a long-standing issue in nuclear seismology, is investigated by studying the phase composition of regional waves from clustered UNE. Regional seismic waves from 67 UNE at the Balapan test site of Kazakhstan, recorded at station Borovoye, are analyzed with a source array technique under the reciprocity theorem. This analysis allows one to obtain the phase velocity composition of the plane waves leaving the source region. Source locations and the original times are obtained from geodetic measurements, a scaling law between event magnitude and depth, and a calibrated Pn travel time curve. Between frequencies of 0.5 and 3.0 Hz the Pn slowness power spectra are concentrated at a phase velocity (vh) of 8.0 km/s. The expected Sn window contains two dominant phases: a scattered P wave with a vh of around 7.1 km/s and a mantle shear wave with a vh of 4.8 km/s. The Lg waves are coherent between 0.5 and 2.0 Hz, with a dominant vh of 4.2 km/s, which is typical in SmS-type waves. The Rg wave at frequencies between 0.5 and 0.8 Hz is dominantly composed of a coherent fundamental mode Rayleigh wave with a vh of 3.0 km/s. At higher frequencies (>0.8 Hz) this coherent Rayleigh wave is not observed in the Rg window because of attenuation during wave propagation. The slower vh of Rg and faster vh of Lg, at which the strong coherent peaks in slowness power spectra are observed, suggest that the dominant components of these two waves are different and they are originated differently in the source region. The proposed Rg-to-S scattering does not appear to be a dominant mechanism for Lg excitation in the Balapan test site. It is also found that the strength of shear waves contained in the expected Sn window varies with local geology much more than the strength of Lg does. Since the Sn is enriched in high-frequency (>1 Hz) content as compared to the Lg, this observation suggests that the local geology influences shear wave excitation at high frequencies more than at lower frequencies.

AB - The mechanism of regional shear wave excitation by underground nuclear explosions (UNE), a long-standing issue in nuclear seismology, is investigated by studying the phase composition of regional waves from clustered UNE. Regional seismic waves from 67 UNE at the Balapan test site of Kazakhstan, recorded at station Borovoye, are analyzed with a source array technique under the reciprocity theorem. This analysis allows one to obtain the phase velocity composition of the plane waves leaving the source region. Source locations and the original times are obtained from geodetic measurements, a scaling law between event magnitude and depth, and a calibrated Pn travel time curve. Between frequencies of 0.5 and 3.0 Hz the Pn slowness power spectra are concentrated at a phase velocity (vh) of 8.0 km/s. The expected Sn window contains two dominant phases: a scattered P wave with a vh of around 7.1 km/s and a mantle shear wave with a vh of 4.8 km/s. The Lg waves are coherent between 0.5 and 2.0 Hz, with a dominant vh of 4.2 km/s, which is typical in SmS-type waves. The Rg wave at frequencies between 0.5 and 0.8 Hz is dominantly composed of a coherent fundamental mode Rayleigh wave with a vh of 3.0 km/s. At higher frequencies (>0.8 Hz) this coherent Rayleigh wave is not observed in the Rg window because of attenuation during wave propagation. The slower vh of Rg and faster vh of Lg, at which the strong coherent peaks in slowness power spectra are observed, suggest that the dominant components of these two waves are different and they are originated differently in the source region. The proposed Rg-to-S scattering does not appear to be a dominant mechanism for Lg excitation in the Balapan test site. It is also found that the strength of shear waves contained in the expected Sn window varies with local geology much more than the strength of Lg does. Since the Sn is enriched in high-frequency (>1 Hz) content as compared to the Lg, this observation suggests that the local geology influences shear wave excitation at high frequencies more than at lower frequencies.

UR - http://www.scopus.com/inward/record.url?scp=31544453888&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=31544453888&partnerID=8YFLogxK

U2 - 10.1029/2005JB003753

DO - 10.1029/2005JB003753

M3 - Article

AN - SCOPUS:31544453888

VL - 110

SP - 1

EP - 11

JO - Journal of Geophysical Research: Solid Earth

JF - Journal of Geophysical Research: Solid Earth

SN - 2169-9313

IS - 12

M1 - B12302

ER -