EEWDisplay

To assist users of ShakeAlert^®, we have developed EEWDisplay (formerly named UserDisplay) a demonstration software, which visualizes alert information from ShakeAlert (Böse et al., 2012). The EEWDisplay runs on a user’s computer, receives XML messages from ShakeAlert and displays their content in a simple and easily understandable way. The application is written in Java and is thus platform-independent. The EEWDisplay demonstration software has the following features:

• Calculation & display of remaining warning time for a given user
• Display of expected MMI intensity at this site
• Description of expected MMI intensity at user site (e.g., “Moderate Shaking expected”)
• Display of estimated magnitude
• Display of the probability of correct alarm
• Calculation & display of P/S-wavefronts
• Display of user site
• Display of a 30-km radius blind-zone around the user for education purpose
• Siren and audio announcement

EEWDisplay pops up automatically whenever an alert message is received (Figure 1). The user can set thresholds for intensities, magnitudes and probability values to reduce the number of reports (Böse et al., 2011). Multiple map layers showing, e.g., fault lines or infrastructure can be added. XML messages received by the EEWDisplay are stored locally in a history folder and can be replayed. A log-file summarizes the key information for each received report. Network Time Protocol (NTP) is used for time synchronization. Further features include password-protection, encrypted communication, and the capability to receive and display heartbeats from the ShakeAlert System to ensure robust communication. The EEWDisplay is currently tested by a group of individuals, emergency responders, and companies throughout California, Oregon, and Washington.

Examples: