Real-time Forecast of Earthquake Hazard in the Next 24 Hours - It is a time-dependent map giving the probability of strong shaking at any location in California within the next 24-hours. Scientists with the Swiss Seismological Service and the Advanced National Seismic System (ANSS) have collaborated to develop techniques that quantify the increased likelihood of future earthquake shaking from earthquake clusters in California. In this system, the probability of strong earthquake shaking (with a Modified Mercalli Intensity of VI or greater) in the next 24 hours is calculated and updated every hour. The system considers all the earthquakes, large and small, that are recorded by the California Integrated Seismic Network (CISN), the California element of the Advanced National Seismic System. For each event, the probability that it will be followed by an earthquake large enough to cause strong shaking is calculated from the known behavior of aftershocks and the possible shaking pattern predicted from historic patterns. These probabilities apply both to aftershocks smaller than the first event and to the possibility that the “aftershock” will be larger than the first event which will then become a foreshock. This has been added to Internet Alerts Subject Tracer™ Information Blog.