Variations in earthquake detection across Ocean Networks Canada’s early warning system
Date
2025
Authors
McMartin, Katie
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Abstract
Ocean Networks Canada’s Earthquake Early Warning (EEW) system has been in operation since 2023. This system uses P wave parameters measured at onshore and offshore stations to predict strong ground shaking and provide advance warning to operators of infrastructure (e.g., trains, planes) and other subscribers. Since its launch the system has detected hundreds of earthquakes. However, when compared to other organizations, the system is missing events. To investigate, Ocean Networks Canada’s earthquake catalog was first compared to those of Natural Resources Canada and the United States Geological Survey. It was found that events are primarily being missed in the northwest and southwest portions of the EEW grid (i.e., in the Explorer plate region south of Haida Gwaii and along the Explorer-Pacific divergent margin) with the system doing a good job of detecting events near Vancouver Island and the Nootka fault zone. In order to determine if events are going undetected because of station geometry (i.e., not enough stations are close enough to the epicentre for P waves to be detected), modelling using ground motion prediction equations was carried out to estimate the minimum detectable magnitude across the grid. In addition, a case study was investigated on a significant undetected event to assess the role of other aspects of the EEW detection algorithm (e.g., epicentre determination). The results showed that the likely reason events are going undetected across the EEW grid is a combination of the geometry of the stations and other aspects of the detection algorithm. The addition of stations from nearby networks (e.g., in Haida Gwaii) and improvements to the epicentre determination algorithm would increase the detection of events across the Ocean Networks Canada Earthquake Early Warning system.
Supervisors: Lucinda Leonard and Alireza Mahani
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Keywords
earthquake detection, earthquake early warning, Ocean Networks Canada, Vancouver Island