The touchscreen sub-system receives both regional EEW broadcast signals and site-specific strong motion data from its own sensors. The LCD display, vertical light bar and audible annunciator deliver continuously updated warning information to operators. If the system receives the USGS EEW signal before seismic waves reach the owner’s site, then the display reflects that information. If the owner is in the ‘blind zone’ the system will analyze the first few seconds of the earthquake (P-wave) and project the intensity and S-wave arrival time. Relay outputs are also available to initiate an automated EEW response (signal owner’s PA system to broadcast a pre-recorded message such as “Earthquake! Drop, Cover, Hold”).

ESS’ Master Seismic Controller (MSC-series) has served industrial and commercial facilities for over 30 years with a proven track-record in response to many real strong motion events. The MSC provides seismically qualified power and circuit protection for the touch-screen early warning system. Additionally, the MSC directly powers & controls a broad spectrum of pneumatic, hydraulic, electric or solenoid actuated valve assemblies. If the owner has opted for EEW-based protection, then the MSC performs a logical ‘OR’ operation with the alarm signal from the EEW sub-system and immediately strokes the owner’s valves to the ‘safe’ position (open or close) in response to the USGS or P-wave algorithm declared event. Alternatively, to lower the risk of false positives, the MSC can perform a logical ‘AND’ operation with the ‘proactive phase’ subsystem- before stroking the owner’s valve(s) closed. Finally, the systems can be operated independently with the EEW signal providing advance warning to personnel and the MSC separately performing site specific 2/2 or 2/3 voting with a variety of sensor configurations.