National Earthquake Information Center

From Scawthorn, C, Earthquakes A historical perspective, in Earthquake Engineering Handbook, Chen, W.-F. and Scawthorn, C Eds., CRC Press, Boca Raton, FL, 2003, pp. 1-2 to 1-4. Originally from National Earthquake Information Center, Golden, CO, http //neic.usgs.gov/neis/eqlists/eqsmajr.html. 

Analysis of seismicity in the Global CMT Project is divided into calendar months. The analysis is initiated 2-3 months after real time and is completed before the end of 4 months. Earthquakes that have the potential to yield robust CMT results are selected for analysis, primarily from the hypocenter catalog of the National Earthquake Information Center (NEIC) of the United States Geological Survey (USGS). The current objective is to attempt analysis for all earthquakes M-w > 5.0. Because of the large uncertainties in traditional magnitudes, all events with mb or Ms > 4.8 are selected for analysis. This typically leads to a monthly list of 300 candidate earthquakes, of which more than half are successfully analyzed. 

Earthworm (http //folkworm.ceri.memphis.edu/ ew-doc/), is the most widely used system for earthquake and volcano-seismic monitoring today. It is an open-source, data acquisition, and earthquake detection framework developed by the US Geological Survey. It comprises of modules that communicate via messages on shared memory rings. It is used in the National Earthquake Information Center, tsunami warning centers, and regional seismic networks. Earthworm is in widespread use at volcano observatories... 

Fig. 3. Location map of events used for tomographic inversions. The map is centred on the approximate centre of the southern Africa array. Locations are from the National Earthquake Information Centre bulletin as archived by the Incorporated Research Institutions for Seismology (IRIS) Data Management Center (James et al. 20016). Published in James et at., GRL28, 2001, fig. 2.

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