Seismic data: waveforms, phase readings and earthquake catalogues
R J Willemann
Digital recording of broadband data has fundamentally changed seismology. Formerly, seismologists picked onsets precisely or completely from a few records. Today, waveforms are usually automatically processed, using more information from each of many more records. Phase reading and event catlogues are still required as indexes into the most useful waveforms. To further facilitate in-depth studeis, however, the International Seismological Centre (ISC) is expanding its services. The ISC is posting newly collected readings to its web site in advance of analysis, and providing links to show for which events and readings digital data are available, and to generate waveform requests on behalf of users for waveforms availbale on the Internet. Second, ISC is working with other agencies and individual researchers to ensure that results from newly developed methods for computing source parameters are fully represented in the Bulletin. An important aspect is showing goodness of fit at each station. Finally, ISC plans to retrieve waveform segments after analysis to make measurements further to thos traditionally included in seismic bulletins, such as signal-to-noise ratio and shear wave splitting.