An earthquake that shook Ottawa and other parts of Ontario and Quebec in June had a magnitude of 5.0. (CBC)

The June earthquake that shook parts of Quebec and Ontario rattled more than just the ground.

Within minutes of the 5.0-magnitude quake, people were furiously posting accounts on Twitter and other social media sites, but official information was impossible to access online.

Natural Resources Canada's earthquake information site was paralyzed by demand, documents released under the Access to Information Act show.

The agency was so overwhelmed with people trying to access the site that it had to enlist the help of the U.S. Geological Survey to get the information out to Canadians.

The crash sent staffers scrambling for more than two hours to find a temporary solution and it took four hours before the whole site was back in full working order.

An official with Natural Resources Canada admitted the crash raised questions about how well prepared the agency is to communicate with Canadians online in the event of a sudden natural disaster such as an earthquake or tsunami.

But in terms of its timing, lack of major damage and the area it affected, the quake was the worst-case scenario for website managers, said David McCormack, program manager for Canadian Hazards Information Systems. It happened in the middle of a workday and was felt in several major cities.

"If you made it 10 times as big, then in big chunks of probably eastern Ontario and western Quebec there wouldn't have been a lot of computer traffic because there would have been damage to the networks and damage to the power system," he said.

"There was none of that, so everybody's computers were just running as normal. So if you put all those reasons together it became almost a perfect storm of demand."

An estimated 20 million people in Ontario, Quebec and the U.S. felt the quake, but there were only reports of minor property damage.

McCormack said technical planning for communications in the event of an earthquake is a different challenge for Natural Resources than it is for other government agencies that sometimes experience surges in online demand.

Revenue Canada, for example, has backups in place to handle the crush when people go online to file their taxes on deadline.

Usually, the Natural Resources web server can handle about a million hits an hour, McCormack said, but in a rare event such as a quake, this doesn't matter.

"The traffic flow essentially goes from zero to everybody wanting it at once as soon as they feel the earthquake," he said.

"So you can have changes in traffic flow that can be hundreds of thousands or even millions of times what you normally expect to get."

The first thing officials did was strip out all the unnecessary features on the site and disable graphics and anything else that ate up bandwidth as they raced to double the capacity of their servers.

Four hours later, the site was back up and working.

A month later, the agency had a chance to test its new system when a 4.1-magnitude earthquake struck between Quebec City and Trois-Rivières. The website had more than a million hits but remained functional, McCormack said.

"If the June event occurred again today we would be able to service the traffic," he said. "What we need to make sure is that under any realistic scenarios we wouldn't find ourselves in that same situation again."

The agency is exploring a better long-term solution.

"It gets to the point where it isn't sensible to just keep throwing more and more hardware at it for events which happen very rarely," he said.

The department is talking to commercial providers who specialize in providing backup capacity for major events and whose services would only kick in when needed.