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Station Statistics Derived from the ISC Bulletin

Description: 

The International Seismological Centre (ISC) receives parametric data such as picked arrival times and amplitude measurement from seismic stations distributed across the globe, including some stations that are reported independently by multiple earthquake monitoring agencies. Approximately 20 million phases are reported to the ISC every year, providing an ideal dataset to evaluate the performance of seismic stations over time. One measure of station performance is the travel time residual of phases reported at the station for all reviewed events in the ISC Bulletin. Variations in the travel time residual at a station can be shown with respect to epicentral distance, and azimuth or over the operational time span of a station. A second metric of station performance is the variations in S-P relative arrival time, which can be used to identify anomalous events with tectonic features such as subduction zones also clearly apparent. third potential measure of station reliability is the reported amplitudes, which can be also used to identify variations or discrepancies associated with individual stations or reporters. This is done by comparing the individual station magnitude with the event magnitude in the Reviewed ISC Bulletin. The fourth and final station quality metric we consider is reported first motion polarities. Several agencies provide first motion polarity readings to the ISC, but this data can be challenging to use due to processing errors, reversed stations and other sources of noise. We compare these reported polarities against reliable reported moment tensors where available, in or order to assess the reliability of polarity measures at a given station, from a given reporter. In this presentation we provide examples of stations showing variations in travel time residual, S-P arrival times, reported amplitudes and first motion polarities, and discuss how this information can be used to identify systematic reporting problems for specific stations or reporters. The station metrics described here are available to view via the ISC website(https://www.isc.ac.uk/stations).

Session: Network Seismology: Recent Developments, Challenges and Lessons Learned - I

Type: Oral

Date: 4/15/2025

Presentation Time: 08:30 AM (local time)

Presenting Author: Thomas

Student Presenter: No

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