An earthquake hit at 1:41 p.m. ET on June 23 south of Echo Lake, Que., 60 kilometres north of Ottawa, near the Ontario border, and was felt across southern and eastern Ontario and western Quebec. (CBC)Ontario and Quebec residents shaken by the magnitude 5.0 earthquake last week are being asked to share their experiences with a federal research project.

The epicentre of the June 23 earthquake was about 50 kilometres north of Ottawa, and it was felt across southern and eastern Ontario and western Quebec, as well as in some U.S. states, including Michigan, Ohio, Pennsylvania, Vermont, New Jersey and New York.

Greg Brooks, a research scientist with the Geological Survey of Canada at the Department of Natural Resources in Ottawa, said it's rare for an earthquake of that magnitude to happen in a highly populated area, so scientists are taking advantage of that.

"This is a fantastic opportunity to get feedback from the public … so we can look at the patterns of shaking throughout the Ottawa area," he said.

He is encouraging people in the Ottawa area and beyond to fill out a questionnaire on the department's Earthquakes Canada website about where they were and how they felt during the earthquake. Questions ask how long the shaking lasted, whether objects fell off shelves and what type of damage there was to the building they were in.

"This helps us better understand how the geology of the area reacts to seismic shaking," he added.

Soft soils shakier

The type of soil or rock underfoot can making a huge difference in the way an earthquake feels, Brooks explained.

"In general, we would expect there to be more seismic shaking on the areas of thick, soft sediment — thick leda clay — than there would be on areas where there's bedrock on the earth's surface."

In fact, the national building code takes that into account, requiring more earthquake resistance in buildings built on clay than those on bedrock.

Not only are there many areas of thick clay in the Ottawa area — such as Orléans — but there are lots of abrupt local changes in geology in the region separated by just a couple hundred metres, Brooks said.

That geology has already been mapped, but researchers don't yet know how closely that corresponds to the way the shaking actually feels.

Researchers hope to be able to superimpose the results of the questionnaire on the geological map of the region, Brooks added — "to see if we are seeing the patterns that we would expect to see based on the geology of the Ottawa area."

As of Tuesday afternoon, the results of 1,107 surveys had been mapped.

As of Tuesday afternoon, 1,107 survey results had been mapped. (Earthquakes Canada)