Since the beginning of June 2004, near-real-time ShakeMaps have been produced in Ontario for earthquakes of M > 2.8 and are posted at http://www.shakemap.carleton.ca/ within minutes of occurrence. ShakeMaps, originally conceived by Wald et al. (1999), provide rapid online assessment of locations, shaking intensities, and expected levels of damage to specific areas, The Nuttli magnitude (MN) 5.4 earthquake which occurred 17 km southwest of Rivière-du-Loup, Québec on 6 March 2005 was the first moderate, well recorded event since the implementation of the Ontario ShakeMap project. It provided a good opportunity to evaluate the performance of ShakeMap in eastern Canada.
The ShakeMap location and moment magnitude, based on the ground-motion centroid, are very close to traditional estimates of these parameters. ShakeMap intensities agree with the preliminary observed intensity results collected based on felt reports submitted online. Recorded ground-motion parameters from this earthquake agree very well with the predictions of empirical ground-motion relations developed for ShakeMap applications by Kaka and Atkinson (2005a), as well as with relations developed by Atkinson and Boore (1995).