Properties of three seismic events in September 2017 in the northern Korean Peninsula from moment tensor inversion

TL;DR

This study analyzes three seismic events in North Korea in 2017 using moment tensor inversion, revealing their source characteristics and fault mechanisms with consistent methodology.

Contribution

It provides a comparative analysis of seismic source properties of three events using uniform inversion procedures and waveform processing.

Findings

M6.3 event has a predominant explosion component.

M4.6 event shows a dominant implosion component.

M3.4 event is mainly a double couple with a normal fault orientation.

Abstract

Moment tensor inversion is conducted to characterize the source properties of the September 3, M6.3, the September 3, M4.6, and the September 23, M3.4 seismic events occurred in 2017 in the nuclear test site of DPRK. To overcome the difficulties in the comparison, the inversion uses the same stations, the same structural model, the same algorithm, and nearly the same filters in the processing of waveforms. It is shown that the M6.3 event is with predominant explosion component, the M4.6 event is with predominant implosion component, while the M3.4 event is with a predominant double couple component (~74%) and a secondary explosion component (~25%). The three seismic events are with a similar centroid depth. The double couple component of the M3.4 event shows a normal fault striking northeastward.