[S01-3] Open session III

[S01-3-06] Difference in energy radiation from earthquakes with similar moment magnitude and focal mechanism: the broadband body-wave magnitudes of the 2014 Ludian and Jinggu, Yunnan Province, China, earthquake

^○Zhongliang Wu¹, Changsheng Jiang¹, Xiaoxiao Song^1,2 (1.Institute of Geophysics, China Earthquake Administration, 2.Earthquake Administration of Hubei Province, Wuhan, China)

The August 3, 2014, Ludian, Yunnan Province, China, MS6.5/MW6.2 earthquake and the October 7, 2014, Jinggu, Yunnan Province, China, MS6.6/MW6.1 earthquake, although with similar moment/surface wave magnitude and similar near-vertical strike-slip focal mechanism, caused sharply different disasters. The former was with fatality/missing up to about 700 and injury about 3,000, and the latter with fatality 1 and injury about 300. To investigate the role of seismic radiated energy in causing such a difference, we analyzed 142 broadband (BB) vertical recordings of the Ludian earthquake and 138 BB vertical recordings of the Jinggu earthquake, with epicentral distance 6o to 80o. We calculated the broadband cumulative body-wave magnitude mBc. It is shown that the mBc of the Ludian earthquake is about 0.3 higher than the Jinggu earthquake. This indicates that, beyond other causes such as social vulnerability, secondary disasters such as landslides, and local effects caused by both the Doppler effect of the seismic source and the site response of the buildings, radiated energy contributes significantly to the difference of the earthquake disasters. The result suggests that in seismological observation and interpretation, routine measurement and fast report of mBc will play an important (and sometimes unique) role in the earthquake emergency response and the rescue and relief actions.