Geoscience Reference
In-Depth Information
triggered tsunami. Within an hour of the earthquake, the WC/ATWC canceled the warning for
the coast areas of British Columbia, Oregon, Washington, and California.
This tsunami warning came only six months after the horriic tragedies, which took place
off the coast of the Indian Ocean during the 2004 tsunami at a time of heightened national
fear of tsunami activity. This warning would be the irst to be issued for the West Coast for a
regional event. Adding to the urgency of decision making action by the TWC was the size and
location of the earthquake, the potential for either earthquake- or landslide-generated tsuna-
mis, and the need to issue a statement before potential inundation occurred along the coast
(within minutes of the earthquake).
THE EVENT AND RESPONSE IN CALIFORNIA
The June 14, 2005, Gorda Plate earthquake (M7.2) violently shook a wide area of Del Norte
and Humboldt Counties, including the cities of Eureka and Crescent City. In assessing the
consequent actions at the state and local levels to the tsunami warning it is critical to recognize
that the “event” was both a local, widely felt, potentially damaging earthquake, and a poten-
tially damaging near-ield tsunami that was the subject of a tsunami warning issued by the
WC/ATWC. As noted above, within ive minutes of the earthquake, oficials at the WC/ATWC
issued a tsunami warning to the California State Warning Center (CSWC) both verbally over the
National Warning System (NAWAS) and as printed copy over the National Oceanic and Atmo-
spheric Administration/National Weather Service (NOAA/NWS) Weather Wire. These messages
were communicated verbally to impacted counties over California's equivalent to NAWAS, the
California Warning System (CALWAS) and by the California Law Enforcement Telecommunica-
tions System (CLETS), a teletype service connecting local law enforcement agencies to the
California Department of Justice. At the same time that oficial notiication to the CSWC and
local governments was occurring, the WC/ATWC notiication was being automatically trans-
mitted over the Weather Wire to subscribers of email and pager notiication services, over the
Emergency Managers Weather Information Notiication (EMWIN) service, over the California
Emergency Digital Information Service (EDIS) to radio and television newsrooms, and over the
California Integrated Seismic Network (CISN) Display to local emergency operations centers.
The WC/ATWC warning was transmitted over the California Law Enforcement Telecommu-
nications System to 22 coastal counties (15 counties directly on the coast and 7 counties that
would be impacted by looding in bays and estuaries), California Highway Patrol (CHP), and
State Parks and Recreation. Within 10 minutes following the notiication over CLETS, CALWAS
was used to issue an initial warning to local emergency responders in the surrounding coastal
area. Unfortunately at the time in which this took place, the CSWC was not suficiently staffed,
leaving only two employees to handle the surge of emergency calls. The local recipient of the
CSWC notiications is the designated Public Safety Access Point (PSAP), usually the county 911
ofice and/or ire, law, and emergency medical dispatch, and for the CLETS teletype messages,
local law enforcement agencies.
CSWC and Ofice of Emergency Services procedures provide for secondary notiication and
