On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus...On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus, we can calculate a large number of values of tectonic ambient shear stress or values of background stress in the place where the earthquake occurs. If nuclear explosions are treated as earthquakes in the calculation, we find that (0 values of nuclear explosions have about 20 MPa, which is obviously higher than average (0 values of earthquakes with the same magnitude. This result can be used to discriminate nuclear explosions from earthquakes.展开更多
In this paper,the nonstationary theory of Wigner Distribution is used to discriminate between underground nuclear explosions and natural earthquakes.Five underground explosions in Kazakhstan region and seven regional ...In this paper,the nonstationary theory of Wigner Distribution is used to discriminate between underground nuclear explosions and natural earthquakes.Five underground explosions in Kazakhstan region and seven regional earthquakes in its adjacent areas have been analyzed.The result shows that the transient spectra of underground nuclear explosions are concentrated in the frequency range of 5-10 Hz,while the transient spectra of natural earthquakes are distributed widely from lower frequency to higher frequency.The transient frequency of nuclear explosions shows linearity in the first stage(0【t【0.75 s)and its initial frequency is negative.The transient frequency of natural earthquakes rapidly changes in a jumping form and its initial frequency alternates between being positive and negative.The obtained results show that the method is more effective than previous ones in discriminating between underground nuclear explosions and earthquakes.This paper also gives a preliminary explanation of the discrepancy展开更多
Earthquake, explosion, and a nuclear test data are compared with forward modeling and band-pass filtered surface wave amplitude data for exploring methodologies to improve earthquake–explosion discrimination. The pro...Earthquake, explosion, and a nuclear test data are compared with forward modeling and band-pass filtered surface wave amplitude data for exploring methodologies to improve earthquake–explosion discrimination. The proposed discrimination method is based on the solutions of a double integral transformation in the wavenumber and frequency domains. Recorded explosion data on June 26, 2001（39.212°N, 125.383°E） and October 30, 2001（38.748°N, 125.267°E）, a nuclear test on October 9, 2006（41.275°N, 129.095°E）, and two earthquakes on April 14, 2002（39.207°N, 125.686°E） and June 7, 2002（38.703°N, 125.638°E）, all in North Korea, are used to discriminate between explosions and earthquakes by seismic wave analysis and numerical modeling. The explosion signal is characterized by first P waves with higher energy than that of S waves. Rg waves are clearly dominant at 0.05–0.5 Hz in the explosion data but not in the earthquake data. This feature is attributed to the dominant P waves in the explosion and their coupling with the SH components.展开更多
文摘On the basis of fracture mechanics earthquake rupture model, the relations between source parameters and (0, the value of tectonic ambient shear stress in the place where the earthquake occurs, have been derived. Thus, we can calculate a large number of values of tectonic ambient shear stress or values of background stress in the place where the earthquake occurs. If nuclear explosions are treated as earthquakes in the calculation, we find that (0 values of nuclear explosions have about 20 MPa, which is obviously higher than average (0 values of earthquakes with the same magnitude. This result can be used to discriminate nuclear explosions from earthquakes.
文摘In this paper,the nonstationary theory of Wigner Distribution is used to discriminate between underground nuclear explosions and natural earthquakes.Five underground explosions in Kazakhstan region and seven regional earthquakes in its adjacent areas have been analyzed.The result shows that the transient spectra of underground nuclear explosions are concentrated in the frequency range of 5-10 Hz,while the transient spectra of natural earthquakes are distributed widely from lower frequency to higher frequency.The transient frequency of nuclear explosions shows linearity in the first stage(0【t【0.75 s)and its initial frequency is negative.The transient frequency of natural earthquakes rapidly changes in a jumping form and its initial frequency alternates between being positive and negative.The obtained results show that the method is more effective than previous ones in discriminating between underground nuclear explosions and earthquakes.This paper also gives a preliminary explanation of the discrepancy
文摘Earthquake, explosion, and a nuclear test data are compared with forward modeling and band-pass filtered surface wave amplitude data for exploring methodologies to improve earthquake–explosion discrimination. The proposed discrimination method is based on the solutions of a double integral transformation in the wavenumber and frequency domains. Recorded explosion data on June 26, 2001（39.212°N, 125.383°E） and October 30, 2001（38.748°N, 125.267°E）, a nuclear test on October 9, 2006（41.275°N, 129.095°E）, and two earthquakes on April 14, 2002（39.207°N, 125.686°E） and June 7, 2002（38.703°N, 125.638°E）, all in North Korea, are used to discriminate between explosions and earthquakes by seismic wave analysis and numerical modeling. The explosion signal is characterized by first P waves with higher energy than that of S waves. Rg waves are clearly dominant at 0.05–0.5 Hz in the explosion data but not in the earthquake data. This feature is attributed to the dominant P waves in the explosion and their coupling with the SH components.
