Earthquake Safety Systems, Inc.
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A M6.5 earthquake struck off the coast of Ferndale, California (south of Eureka CA) on Saturday, Jan. 9, 2010.  The earthquake shook structures to the south of the Oregon border.  Power outages, broken windows and damage to business merchandise were reported.  The water distribution system operated by the Humboldt Community Services District (HCSD) reportedly suffered minor damage.  HCSD management was pleased that the ESS MSC-W Master Seismic Controller performed as designed- automatically closing the outlet valve on the monitored water tank. 
10 miles to the north, the McKinleyville Community Services District (MCSD) has two (2) tanksites instrumented; each with ESS Model MSC-W Master Seismic Controllers.  Neither tank closed automatically in response to the shaking felt in the area.  However, although only 10 miles away, no damage was reported by MCSD with respect to its water distribution system. 
Relying solely on a broadcast earthquake early warning (EEW) alarm signal would have unnecessarily interrupted water service in the City of McKinleyville- blocking the fire department's access to water for fire suppresion.
This is another example of the importance of site specific earthquake actuated automatic shutoff systems- wherein processes and media (gas, water, etc.) are only interrupted if the shaking AT THE OWNER'S FACILITY exceeds the owner's operating criteria.

Ferndale, CA M6.5 Earthquake