Seismograph Networks Across Canada: Building on the Legacy of LITHOPROBE and POLARIS

FIONA A. DARBYSHIRE*1

1Centre de recherche GEOTOP, Département des Sciences de la Terre et de l’Atmosphère, Université du Québec à Montréal, Canada (darbyshire.fiona_ann@uqam.ca).

Canada has a long history of far-reaching geophysical programmes to study the structure and evolution of the continental lithosphere. The best known is the pan-Canadian LITHOPROBE project, which brought together scientists from several disciplines in the Earth sciences. The project spanned 10 transects, sampling lithospheric structure from Archean to present, and was active from 1984 to 2005.

Passive-source studies played a relatively small role in LITHOPROBE, so the subsequent POLARIS (Portable Observatories for Lithospheric Analysis and Research Investigating Seismicity) project concentrated exclusively on this component of Solid-Earth research, comprising temporary deployments of seismic and magnetotelluric stations. Active from 2001 to 2014, POLARIS also paved the way for a series of smaller projects, spearheaded by individual institutions, to install further broadband seismic networks in regions not previously studied.

More recently, Canadian seismology has benefitted from collaboration with the US EarthScope programme, including the deployment of Transportable Array seismographs in eastern and northwestern Canada, along with cross-border FlexArray projects. These have brought a wealth of new data, leading to important new discoveries about the evolution of the Laurentian continent.

An ambitious new pan-Canadian initiative is currently under development. The EON-ROSE (Earth-system Observing Network – Réseau d’Observation du Système terrestrE) project aims to install a network of Earth-system observatories across Canada, ranging from broadband seismographs and GNSS through critical-zone monitoring facilities, to magnetospheric observations. The Solid-Earth component will build on the success of EarthScope, and will begin soon with a pilot project, the Canadian Cordillera (CC) Array, in western Canada.

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