以下、アメリカの自然科学者からのメールです。 Thanks, Brother--using earthpipes is easy. There's a circular fault around the Yellowstone Caldera. The diameter of the caldera is approximately 50 kilometers. The seismic activity there was dangerous and a big eruption was imminent.
We placed one earthpipe per every 11 kilometers around the circumference one day. After that day there has been no seismic activity within that caldera. That was in November, 2004.