测定的震级之间不应相互换算

新的强制性国家标准《地震震级的规定》（GB17740—2017）规定了地方性震级M_L，短周期体波震级m_b，宽频带体波震级m_B（BB），面波震级M_S，宽频带面波震级M_S（BB）和矩震级M_W等6种震级的测定方法，并将矩震级M_W作为对外发布的首选震级。由于不同震级所使用的地震波类型不同，所表示的意义也不同，因此新标准明确要求：测定的震级之间不应相互换算。为了帮助相关技术人员更好地理解并能在实际工作中正确使用新国标此项规定，本文从地震的复杂性、震级的多样性、新旧国标的一致性，以及使用地方性震级M_L转换成面波震级M_S开展地震速报所产生的一系列问题等方面，阐述制订该规定的主要原因。

The measured magnitude should not be converted to each other

In new state mandatory standard "General ruler for earthquake magnitude" (GB17740-2017), 6 kinds of magnitudes such as local magnitude M_L, short period body wave magnitude m_b, broad band body wave magnitude m_B(BB), surface wave magnitude M_S, broad band surface wave magnitude M_S(BB) and moment magnitude M_W are defined, and moment magnitude M_W is chosen as the preferred magnitude to be released. Because of the different seismic wave periods used by different magnitudes, their significance is different. Therefore, the new standard clearly requires that the magnitude of the measurement should not be converted to each other. In order to help the relevant technical personnel better understand and use the new national standard in the actual work, in this paper, the main reasons for this rule are expounded from the earthquake complexity, the magnitude multiformity, the consistency of the new and old national standard, and a series of problems caused by using of the local magnitude M_L conversion into the surface wave magnitude M_S in the earthquake parameters fast report, and so on.