This is Scientific American 62nd Science.

I'm Julia Rosen.

Got a minute?

2002 was a tough year for the people who live along the shores of Lake Kivu in the Democratic

Republic of Congo. It started off with a bang when the

near a gango volcano erupted in January, and it tailed off with a shudder when a magnitude

6.2 earthquake struck the region in October, both events devastated local

communities and their close timing struck some scientists as suspicious.

We were wondering if there could be a link, so a causality between those two major geological events.

Christel Wattier, a geologist at Pennsylvania State University,

from studying radar images of the ground, taken before and after the January eruption,

Whatier knew that Lava didn't just spew out of the volcano.

It also wedged itself into cracks in the crust, forming what geologists call a dike.

So you can think of it as like a blade shape type of magma intrusion, moving from depths toward the surface. It's very fast, a few hours,

a few days and it can penetrate tens of kilometers of crust.

Dykes are common in rift zones,

like East Africa and Iceland,

where tectonic forces are slowly ripping Earth's crust apart.

And they're known to cause small earthquakes

right when they happen.

But Wattee wondered if Dykes might also be capable of triggering large earthquakes by pushing the ground apart and affecting nearby faults.

You will add more stress on a weakness surface which is a fold and so if you add enough stress on it you can trigger failure on the fault.

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