Abstract

The Pacific Tsunami Warning Center’s (PTWC’s) core mission consists in saving lives and minimizing property damage through the issuance of timely, effective tsunami warnings and threat messages. For this purpose, the center relies primarily not only on the analysis of near‐real‐time seismic data streams provided by established networks such as the Global Seismic Network (GSN), but also by an increasing number of stations contributed by regional seismic networks (RSNs) from around the world. We used theoretical computations of the detection time of the first arriving P wave as a proxy to highlight the areas where RSN contributions have the greatest operational impact. To this goal, the P‐wave detection times computed for the GSN provided a baseline to isolate the contribution of the RSN in the form of spatially distributed detection time gains. Inspection of the resulting global maps reveals detection time gains of more than 3 m for Hawaii, Alaska, the east and west coasts of the United States, South America, New Zealand, the southwest Pacific, Australia, and the Sunda arc. Despite higher density of GSN baseline stations across the U.S. west coast and the eastern Caribbean, contributions from RSNs result in detection time gains of more than 2 m. These gains in earthquake detection speed correlate well with the continuous increase in the number of stations ingested into the PTWC system and the gradual reduction of the operational median response time to under 6 m from origin during the last 5 yr. These results allow us to conclude that fulfillment of the PTWC’s international and domestic tsunami warning responsibilities critically depends on the support of the RSNs contributing data to PTWC’s daily operations.

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