Abstract:Using the broadband digital seismic data recorded by the Yunnan Digital Seismic Network in Yunnan and its surrounding areas during 2000~2017,according to the determination method of the New National Standard "Earthquake Magnitude Regulation" (GB17740-2017),the same set of software should be used to re-measure manually the local magnitude ML,the surface wave magnitude MS,the wide band surface wave magnitude MS(BB),the short period body wave magnitude mb,the wide band wave magnitude mB(BB) and the moment magnitude MW. The relationship between different magnitude is compared with the general linear regression and orthogonal regression methods respectively,and the empirical relations between them are given. The results show that there is little difference between the various magnitude:① When M<4.5,and the size of the earthquake can be better represented by the local magnitude ML,and can reflect the regional characteristics more fully. When 4.5 ≤ M < 8.0,the wide band surface wave magnitude MS(BB) and the moment magnitude MW can better represent the magnitude of the earthquake. However,the determination of moment magnitude MW takes a certain amount of time. So in the rapid reporting work and earthquake emergency response,MS(BB) can be used to indicate the size of the earthquake. MS(BB) determination method and international standards,eliminate 0.2 of the magnitude deviation. ② For surface wave magnitude MS and wide band surface wave magnitude MS(BB),the calculation formula and the regression function are different. The MS ratio MS(BB) system is about 0.2 higher. The short period body wave magnitude mb is smaller than the wide band Body wave magnitude mB(BB),and the overall is about 0.2. The main difference should be in the simulation mode. ③ Wide band surface wave magnitude MS(BB) and wide band wave magnitude mB(BB) are directly measured vertically to the original wide band record,eliminating the waveform simulation link. In addition,compared to the determination of mB(BB) epicenter distance requirements greater than 5 degrees,many stations will be limited. MS(BB) is more conducive to regional network measurement. ④ When 3.5 ≤ ML ≤ 6.5,ML is larger than MW as a whole. When MS ≥ 3.5,MS,MW is also the overall size,and with the increase of the magnitude,the deviation value is on the rise. ⑤When M ≥ 8.0,the surface wave magnitude appears saturated,with the moment magnitude MW to indicate the size of the earthquake with M ≥ 8.0.