- 125 - OD1-121
Source characteristics of the October 9, 2006 underground nuclear explosion in North Korea
Tae-Kyung Hong*
Department of Earth System Sciences, Yonsei University
Yonsei University, Deptartment of Earth System Sciences, Shinchon-dong, 134, Seodaemun-gu, Seoul 120-749, South Korea
02-2123-2667 [email protected]
요 약
The October 9, 2006 underground nuclear explosion (UNE) test in North Korea was well observed in dense regional seismic networks deployed in South Korea, Japan and China. This unique observation of a UNE allows extensive investigation of the source properties of UNE by regional phases, which was not feasible previously due to spatially-sparse regional monitoring. We invert for Pn, Pg, Sn and Lg source spectra of the UNE of North Korea by determining the moment, corner frequency, overshoot parameter, attenuation factors and frequency power-dependence terms. The determined overshoot parameters of P phases are close to theoretical expectations, while those of S are close to zero. The inverted source spectra agree well with theoretical curves based on UNE source-spectral models. The low overshoot parameters for Sn and Lg suggest that their excitation sources may be different from those for Pn and Pg. Amplitude ratios between P phases (Pn, Pg) and Lg are useful for discrimination between UNE and natural earthquake at frequencies greater than 2-8 Hz.
