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A scheme to set preferred magnitudes in the ISC Bulletin


One of the main purposes of the International Seismological Centre (ISC) is to collect, integrate and reprocess seismic bulletins provided by agencies around the world in order to produce the ISC Bulletin. This is regarded as the most comprehensive bulletin of the Earth’s seismicity, and its production is based on a unique cooperation in the seismological community that allows the ISC to complement the work of seismological agencies operating at global and/or local-regional scale. In addition, by using the seismic wave measurements provided by reporting agencies, the ISC computes, where possible, its own event locations and magnitudes such as short-period body wave m b and surface wave M S . Therefore, the ISC Bulletin contains the results of the reporting agencies as well as the ISC own solutions. Among the most used seismic event parameters listed in seismological bulletins, the event magnitude is of particular importance for characterizing a seismic event. The selection of a magnitude value (or multiple ones) for various research purposes or practical applications is not always a straightforward task for users of the ISC Bulletin and related products since a multitude of magnitude types is currently computed by seismological agencies (sometimes using different standards for the same magnitude type). Here, we describe a scheme that we intend to implement in routine ISC operations to mark the preferred magnitudes in order to help ISC users in the selection of events with magnitudes of their interest.

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We thank Bruce Presgrave for the information regarding the generic magnitude M G . Also, thanks to all agencies that took time and effort to put their magnitude procedures available to us. This work is supported by the National Science Foundation Grant EAR-1417970 and USGS Grant G14AC00149.

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Correspondence to Domenico Di Giacomo.

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The data used in this work is freely available via the ISC website ( The figures were drawn using the Generic Mapping Tool (GMT, Wessel and Smith 1998) software.

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Di Giacomo, D., Storchak, D.A. A scheme to set preferred magnitudes in the ISC Bulletin. J Seismol 20, 555–567 (2016).

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  • Earthquake magnitude
  • Seismological bulletins