Many seismological centers now have Web sites that provide real-time earthquake information. Webmasters who maintain these sites are aware that the daily rate of “hits” to, or views of, the sites' pages increases when an earthquake attracts public and/or media attention. However, many seismic network operators and webmasters may not be fully aware of how abrupt and rapid a hits surge might be following a felt earthquake as people visit the Web pages to find out information about what they have felt.

Within 1 minute to a few minutes of an earthquake's occurrence, the European-Mediterranean Seismological Centre's (EMSC) Web site (http://www.emsc-csem.org) can detect the surge in hits (Figure 1). At EMSC, we have developed a system to use this information to discriminate felt events regardless of their magnitude, and to gather in situ information on an earthquake's effects within 10–20 minutes of its occurrence—at a time when any such information is critical to evaluating its impact.