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Low-Latency Digitization, Communication and Alerting for Earthquake Early Warning Systems: Güralp Minimus

Session: Earthquake Early Warning System in the Americas: The On-Going Effort and the State of the Art II

Type: Oral

Date: 4/20/2021

Presentation Time: 10:45 AM Pacific

Description: 

Earthquake Early Warning Systems (EEWS) must combine low latency digitization, communication and computational processes to be effective. This maximises the time between the characterization of an event and the warning of the population, thereby providing the longest warning time. Güralp Systems Ltd. (GSL) has developed the Minimus digitizer with a range of smart features that reduces latency to 40ms from signal input to output.

The Minimus makes use of industry standard processing techniques such as causal FIR filters to reduce the digitization delay within the digitizer. GSL has also developed and equipped Minimus with our GDI-link streaming protocol to further reduce the delays in data communication. GDI-link streams data sample-by-sample upstream and will dynamically adjust to the available bandwidth, therefore providing a fast a reliable communication protocol than traditional packetization protocols. This results in the received data packets having a dramatically lower mean latency when compared to conventional SEED-link for example.

Minimus combines familiar STA/LTA algorithms with simple machine-readable event messages to alert operators and populations to impending ground shaking. When in a triggered state, the Minimus will instantly send a Common Alert Protocol (CAP) event message to a designated receiver containing the station metadata that indicates an event has occurred. The Minimus will locally compute the PGA, PGV and PGD parameters from the triggered event and will subsequently send these calculations as a secondary CAP message. CAP messaging makes use of existing internet infrastructure and is already widely used in public communications which will aid EEW network operators with regards to implementation.

The Minimus has been designed as either a standalone digitizer or can be integrated into the Fortimus accelerometer and the Certimus digital seismometer. The integrated systems provide compact and easy to deploy systems that are suitable for widescale EEW deployments.

Presenting Author: James Lindsey

Student Presenter: No

Authors