Geothermal energy, heat energy from the earth's interior, is used to generate electricity in a variety of places throughout the world.
No. Scientists agree that drilling into a volcano would be of questionable usefulness. Not withstanding the enormous expense and technological difficulties in drilling through hot, mushy rock, drilling is unlikely to have much effect.
If another catastrophic caldera-forming Yellowstone eruption were to occur, it quite likely would alter global weather patterns and have enormous effects on human activity, especially agricultural production, for many years.
Yes. Over the past 640,000 years since the last giant eruption at Yellowstone, approximately 80 relatively nonexplosive eruptions have occurred and produced primarily lava flows. This would be the most likely kind of future eruption.
Not usually. Earthquakes associated with eruptions rarely exceed magnitude 5, and these moderate earthquakes are not big enough to destroy the kinds of buildings, houses, and roads that were demolished in the movie.
There is no evidence that a catastrophic eruption at Yellowstone is imminent, and such events are unlikely to occur in the next few centuries. Scientists have also found no indication of an imminent smaller eruption of lava. 
Metropolitan Portland, Oregon, like Auckland, New Zealand, includes most of a Plio-Pleistocene volcanic field.
Ground deformation (swelling, subsidence, or cracking) is measured with a variety of techniques, including Electronic Distance Meters (EDM), the Global Positioning System (GPS), precise leveling surveys, strainmeters, and tiltmeters.
Lahars are commonly initiated by: 1) large landslides of water-saturated debris, 2) heavy rainfall eroding volcanic deposits, 3) sudden melting of snow and ice near a volcanic vent