A pulse on the pulse of Canada
By Lauren Plews

OTTAWA — It looks like an ordinary office. Bookcases full of books, a plant by the window, pictures of children on a desk covered in papers. However, this is no ordinary office and the woman sitting at the desk has no ordinary office job. With one click of her mouse she has her hand on the pulse of the pulse of Canada.

Dr. Gail Atkinson is a geophysicist at Carleton University in Ottawa. She is part of the Polaris Consortium. Polaris stands for Portable Observatories for Lithosphere Analysis and Research Investigating Seismicity.

For the past three years, Atkinson and a group of scientists have been studying earthquakes in Canada and around the world to determine how to deal with these disasters. The team has set up three seismographic arrays in Ontario, B.C. and the Northwest Territories. Each array will have thirty seismographs.

Every seismograph is linked to a satellite, which sends data directly to Atkinson and other members of the team via the Internet. This allows them to see earthquakes across Canada and the world in real time right at their computers.

One of the Polaris units. The seismograph is in the metal drum.

Seismographs

“Each seismograph is extremely sensitive,” says Isa Asudeh from the National Research Council of Canada. Asudeh is the program manager for Polaris. He says the seismographs are able to detect any earthquake in the world that registers over five on the Richter scale.

Seismographs must be placed in areas that have little “noise” because they are highly sensitive. Noise can be anything from wind in the trees to vibrations caused by cars. Any thing that movies the surface of the earth even slightly causes this noise and can alter the seismographs ability to record earthquakes. This means that all the units in the array have to placed in remote areas where noise can be kept to a minimum.

It's key that the units are as low maintenance as possible because of their remote location. To this end, they are solar powered and the seismographs are place in metal drums so that they are not damaged by weather and other problems. Each unit also has a small dish set up so that signals can be sent o the satellite.

Some of the seismograph locations in Ontario.

Atkinson hopes these seismographs will enable them to truly know what happens during an earthquake. She says that the key to understanding earthquakes is to “understand their waves.”

Earthquakes occur after a buildup of energy in the earth’s crust bursts and is suddenly released. The release of this energy moves the earth in waves.

All in the waves

“During an earthquake there are two main types of waves,” says Asudeh. P-waves for primary and S-waves for secondary. P-waves are compression waves that move the earth up and down in the same direction as the wave is moving . S-waves are shearing waves and they twist the earth from side-to-side or up-and-down in the opposite direction that the waves are moving. “The S-waves are the most severe and they are what cause the damage during an earthquake,” Atkinson says.

“There is no way to predict where or when an earthquake will happen, but the ability to know the difference between P- and S-waves will change our warning systems,” Atkinson says.

Though both P- and S-waves start at the same time, at the origin of the earthquake, the P-waves move faster. Think of a water droplet falling into a smooth pool. The droplet makes rings that move out from the centre. As the waves move farther from the source the P- and S-waves get farther apart from each other.

here these waves register on the seismographs tell scientists how far the seismograph is from the origin of the quake.

“Though the time between the P- and S-waves may only be a matter of seconds, our hope is that with the ability to determine which is a P- and which is an S-wave, a better warning system can be put in place," Atkinson says.

This warning system could include automatic shutoffs for gas lines and nuclear power plants that would help decrease damage. “The warnings could give people just enough time to get to a safer location,” Asudeh says.

Image of an earthquake and the way the waves move out from the origin.

This is very important for areas like B.C. where they know they are situated on an active and dangerous fault line, Asudeh says. Ontario is another story. “There is little activity compared to places like B.C. but with the sensitivity of the seismographs Polaris scientists can gather a great deal of data from small earthquakes in Ontario,” Asudeh says.

Map to buried treasure

“The seismographs in the Northwest Territories have a special application,” Atkinson says. The units of the array have been set up in areas surrounding the Ekati diamond mine. According to Statistic Canada the mine is the first major diamond mine in Canada. When it reachesfull production, it will produce four per cent of the world's diamonds — making it one of the 15 largest diamond mines world-wide.

“The hardest part about diamonds is finding them,” Atkinson says. Diamonds are formed deep in the earth and are brought up in pipes called kimberlites, says Erin Palmer of the C. S. Lord Northern Geoscience Centre.

These carrot-shaped pipes in the earth act like a sort of volcano. When they burst they bring material from deep in the earth nearer to the surface.

Kimberlites are found by digging deep holes to take core samples, Atkinson says. These samples can cost upwards of a million dollars and disturb the environment as well. The seismographs can shed light on what the area’s earth is made of, Asudeh says.

If certain seismic patterns can be found in areas where there are known kimberlites, then other areas with similar patterns may have diamonds, too. “It would mean the ability to find diamonds in an unobtrusive way,” says Atkinson. “No money would be wasted obtaining core samples in areas where there were no diamonds.”

Atkinson says that the geological make-up of northern Ontario and Quebec is similar to that of the Northwest Territories. If their seismic activity turns out to be similar there may be diamonds.

Atkinson says the arrays should be complete within the next year with 30 seismographs in each. Atkinson would like to see the addition of global positioning monitors to each unit. Then they'll have not only detailed records of the earthquakes around the country, but they'lll be able to record how the earth’s crust is moving.