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A Review of Timing Accuracy Across the Global Seismographic Network

Session: Network Seismology: Keeping the Network Running While Integrating New Technologies [Poster]

Type: Poster

Date: 4/22/2021

Presentation Time: 11:30 AM Pacific

Description: 

The accuracy of timing across a seismic network is important for locating earthquakes as well as additional studies that use phase arrival information (e.g., tomography). The Global Seismographic Network (GSN) was designed with a timing goal of 10 ms. In this work, we provide a brief overview of how timing is kept across the GSN and discuss how clock quality metrics are embedded in Standard for the Exchange of Earthquake Data (SEED) data records. Specifically, blockette 1001 contains the timing quality field which can be used to identify time periods when poor clock quality could compromise timing accuracy. To verify the timing across the GSN we compare cross-correlation lags between co-located sensors from January 1, 2000 to January 1, 2020. We find that the mean error is less than 10 ms with much of the difference likely coming from the method or uncertainty in the phase response of the instruments. This suggests that timing across the GSN is potentially better than 10 ms. We conclude that unless clock quality is compromised (as indicated in blockette 1001), GSN data’s timing accuracy should be suitable for most current seismological applications which require 10 ms accuracy. To assist users, the GSN network operators have implemented a “gsn_timing” metric available via the IRIS Data Management Center that helps users identify data with substandard timing accuracy (the 10ms design goal of the GSN).

Presenting Author: Adam Ringler

Student Presenter: No

Authors