Publication Date:
2019
Description:
〈span〉〈div〉Summary〈/div〉North Korea conducted sixth underground nuclear test on September, 3〈sup〉rd〈/sup〉, 2017. Unlike its previous tests, a rare subsequent collapse event occurred after about 8.5 minutes. As two types of distinctive shallow seismic events, accurate inversion of their focal mechanisms is important for event identification for CTBT. In this paper, we carry out moment tensor inversion of the nuclear test and the collapse event with gCAP using waveform data from dense regional seismic stations. And their focal mechanisms are further constrained with surface wave amplitude ratio. The results show that the surface wave amplitude ratio has further constraints for screening the waveform inversion results. The resolution of the focal mechanism inversion for the nuclear test is high, which is close to a Crack source. However, the resolution for the collapse event inversion is not so high and the source type is difficult to be accurately determined. One reason of the poor resolution for the collapse event may be due to the limited availability of high quality data, and complexity of the source process might be another factor.〈/span〉
Print ISSN:
2051-1965
Electronic ISSN:
1365-246X
Topics:
Geosciences
Published by
Oxford University Press
on behalf of
The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
