Seismic Safety Margins Research Program. Regional relationships among earthquake magnitude scales
The seismic body-wave magnitude m{sub b} of an earthquake is strongly affected by regional variations in the Q structure, composition, and physical state within the earth. Therefore, because of differences in attenuation of P-waves between the western and eastern United States, a problem arises when comparing m{sub b}'s for the two regions. A regional m/sub b/ magnitude bias exists which, depending on where the earthquake occurs and where the P-waves are recorded, can lead to magnitude errors as large as one-third unit. There is also a significant difference between m{sub b} and M{sub L} values for earthquakes in the western United States. An empirical link between the m{sub b} of an eastern US earthquake and the M{sub L} of an equivalent western earthquake is given by M{sub L} = 0.57 + 0.92(m{sub b}){sub East}. This result is important when comparing ground motion between the two regions and for choosing a set of real western US earthquake records to represent eastern earthquakes. 48 refs., 5 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission (NRC), Washington, DC (United States); USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5073993
- Report Number(s):
- NUREG/CR-1457; UCRL-52745; ON: TI86002777; INIS-XA-N--031
- Country of Publication:
- United States
- Language:
- English
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