# Forecasting the Largest Expected Earthquake in Canadian Seismogenic Zones

## TL;DR

This study uses the ETAS model to forecast earthquake risks in Canada, identifying British Columbia as the highest-risk region.

## Contribution

The study applies the ETAS model to Canadian seismic zones to forecast earthquake probabilities and assess regional risks.

## Key findings

- British Columbia has a 66% chance of a M7.5+ earthquake in 30 years.
- Alberta has a 4% chance of a M6.5+ earthquake in 30 years.
- Eastern Ontario and Southern Quebec face a 74% chance of a M6.0+ earthquake in 30 years.

## Abstract

Significant earthquakes can cause widespread infrastructure damage, social implications, and substantial economic losses. To mitigate these impacts, earthquake forecasting models have been developed to estimate earthquake occurrences and improve recovery efforts, with the Epidemic-Type Aftershock Sequence (ETAS) model being the most informative statistical framework for characterizing earthquake sequences. In this study, the ETAS model is used to estimate the model parameters for seismicity in Canada using the historical earthquake catalogue and to forecast long-term seismicity for seven different regions in Canada. Furthermore, the model is used to generate synthetic earthquake catalogues in order to assess its ability to replicate observed seismic patterns. The study identifies the southwestern region of Canada, associated with the coastal area of British Columbia, as being at the highest seismic risk, with a 66% exceedance probability for M7.5 events or above to occur in 30 years. In contrast, Alberta features the least seismic risk, with a 4% exceedance probability for events above 6.5 magnitude. For southeastern Canada, associated with Eastern Ontario and Southern Quebec, an exceedance probability of 74% for events above 6.0 magnitude poses the potential for significant damage due to the larger exposed population. Moreover, the resulting seismicity maps show the model’s capability for real-events analysis, but improvements are needed for further applications.