2002 was a tough year for the people who live along the shores of Lake Kivu in the democratic Republic of the Congo. It started off with a bang, when the Nyiragongo 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." Christelle Wauthier, a geologist at Pennsylvania State University. From studying radar images of the ground taken before and after the January eruption, Wauthier 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.