Eastern North America experiences large intracratonic earthquakes that are not well
understood but pose a risk to urban centers and other infrastructure. Compilation of
regional earthquake epicentres for south-central Ontario and western Quebec demonstrate
a close association with sutures and failed rifts (the St. Lawrence Rift) recording the formation and breakup respectively of successive supercontinents Rodinia and Pangea.
Where seismic potential could be underestimated through lack of historical seismicity or
where little is known about active faults, lake deposits can provide a valuable record of
past seismic shaking events in the form of sediment deformation structures (i.e.
‘seismites’). In central Canada, the lacustrine seismographic record began approximately
10,000 years before present with the retreat of the Laurentide Ice Sheet, older records having been removed by glacial erosion. Most bedrock lake basins are structurally-controlled
and underlain by the same Precambrian basement structures (shear zones, terrane boundaries and other lineaments) implicated as the source of ongoing mid-plate earthquake
activity. High resolution seismo-stratigraphic data presented here supports the model that
ongoing mid-plate earthquake activity is a consequence of brittle deformation of the upper
crust of the North American plate. Such activity appears to have been greatest during
deglaciation but continues today. The detailed geophysical and sedimentary studies, as
shown here, have major societal relevance in areas of eastern North America affected by
intraplate earthquakes. The recognition and mapping of earthquake related features in
lakes for seismic risk analysis is a means of constraining seismic recurrence intervals and
more realistically assess seismic risk across the populated area of Ontario and Quebec
where events occur on time scales much longer than recorded history. / Dissertation / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/15480 |
| Date | January 2014 |
| Creators | Doughty, Michael |
| Contributors | Eyles, Carolyn, Geography and Earth Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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