Lake Huron lies on the Great Lakes tectonic zone, a fault-line that stretches from South Dakota, US, to Sudbury, Ontario. It has not been terribly active, with the largest recent quake being the 4.6 earthquake in 1975 in Morris, Minnesota.

However, strong tremors originating elsewhere have also been felt in the Great Lakes region, for instance

The earliest, well-recorded history of earthquake tremors felt in the Michigan Territory resulted from the great earthquakes centered in the lower Mississippi Valley near New Madrid, Missouri in 1811and 1812. As many as nine tremors from the New Madrid earthquake series were felt in the Detroit region (von Hake, 1973). At Orchard Lake, Michigan, it was reported that on December 17, 1811 “the Indians said the waters of the lake began to boil, bubble, foam and roll about as though they had been in a large kettle over a hot fire, and that in a few minutes up came great numbers of turtles and hurried to the shore, upon which they had a great turtle feast” (Hobbs, 1911). As late as February, 1976, several tremors of low intensity were again felt in the Detroit area, the epicenter or focal point of origin being unofficially located in northern Ohio.
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The effects of the New Madrid series earthquake point out that it is rather strange to restrict the earthquake data for the region to 180 years in the past, a date which just manages to exclude the New Madrid earthquake, the largest set of earthquakes ever to strike North America.

The Provincial Council of Women of Ontario (PCWO) note that an earthquake

…may appear to be very unlikely, however the location of the proposed repository in an Ordovician sedimentary formation increases the risk [if one should strike]. For instance, in a study done for NWMO, Characterizing the Geosphere in High Level Radioactive Waste Management, independent geologist Professor J.F. Sykes of the University of Waterloo notes that “Beneath the Bruce Nuclear Power Development on Lake Huron, the Ordovician shales of the Michigan Basin are likely to have hydrolic conductivities in the range of 10 to the 11th to 10 to the 14th m/s at depths of 500m (Moltyaner et al 1995). The pore water in the formation is highly saline and stagnant. However, the physical properties of shale can undergo significant irreversible alteration with low or moderate changes in temperature, or stress.” An additional caution is the location of the Bruce site on the Findlay-Algonquin Arch, along which there are active faults.

PCWO recognizes that the EIS will require a quite detailed description and analysis of the “geotechnical and geophysical hazards, however PC WO recommends that the Guidelines should specifically require the Joint Panel to use independent, third party evidence as to the stability of the Ordovician sedimentary and the earthquake potential. Only in this way may the Panel be certain that the underground repository for nuclear waste in this area does not pose a risk to this very special ecological area and a Great Lake that is in close proximity to and supplies fresh drinking water to millions of residents on both sides of the border. This is not an unreasonable requirement, given the huge ramifications of any “significant irreversible alteration” or an earthquake.

Likewise, the PCWO notes that

According to retired geologist J. Robert Janes (M. Eng. Geology), author of the textbook Geology and the New Global Tectonics, and co-author of Airphoto Interpretation and the Canadian Landscape:

“The proposed Bruce site lies on the northwestern flank of the Findley-Algonquin Arch. A known uplift that is seismically active, the Arch is no doubt block-faulted in many areas and connected to the Ottawa-Bonnechere Graben, the Hudson River Fault, the St. Lawrence Fault and Logan’s Line.

It is very important therefore to consider the periodicity, clustering and magnitude of earthquakes, but foolish to give assurances based on data that goes back only one hundred and eighty years, and to only 1 earthquake of magnitude 5, which is severe enough to give warning. It is also important to document post-glacial rebound, and the repetitive periods of continental glaciation, since we are now 5,000 years beyond when the next phase should have occurred, and have no assurances that another phase will not return at some point in the study’s forward time scale of ten million years. In addition, there need to be bathymetric studies of the floor of Lake Huron next to the waste burial site. These would most certainly show uplifted and downfaulted blocks, rather than the smooth cross-section shown by the proponent.”

In light of these independent pieces of information from two geologists, PCWO feels that the proponent appears to be presenting insufficient information to fit their case for a repository, and that there is a need for independent evaluation of their data.

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