New magnitude scales M (L) and spectrum-based M (w) for the area around Shanxi Rift System, North China

作者：Li Bin^*; Havskov Jens; Ottemoller Lars; Sorensen Mathilde Bottger

来源：Journal of Seismology, 2015, 19(1): 141-158.

DOI：10.1007/s10950-014-9455-y

• Earthquake
• Magnitude scale
• Moment tensor inversion
• Shanxi rift system
• Shanxi Seismic Network

A new locally calibrated M (L) scale was derived for the area around the Shanxi rift system, North China, from 83 events recorded on 56 stations of the Shanxi Seismic Network (SSN) resulting in 2,633 observations during the period of 2008-2012. It is expressed as M (L) = log(A) + 0.80log(R) + 0.00187R -aEuro parts per thousand 1.4, where A is the maximum amplitude of vertical component in nanometer (nm) measured on a simulated Wood-Anderson seismogram at a hypocentral distance R. The new M (L) scale is valid for distances up to 600 km and is an improvement comparing to the currently used SSN scale, with a reduction in variance of 39 % in magnitude residuals. The moment magnitude M (w) was also calculated for the whole data set based on spectral analysis. To validate the Q-function used for spectral M (w), we carried out moment tensor inversion for 17 moderate size events and selected the regional attenuation model which gave spectral M (w) on average closest to moment tensor M (w). The most appropriate Q-function was found to be Q(f) = 299.4f (0.563). The determination of the M (w) magnitudes makes it possible to derive a relationship between the M (L) and M (w) scales of this region, which is expressed as M (w) = 0.85M (L) + 0.58, similar to relationships found elsewhere for similar tectonic environments.

• 出版日期2015-1