Earthquakes & Volcanoes

Earthquakes, volcanism, and hydrothermal features go hand in hand at Yellowstone. The underground plumbing of hot water and magmas beneath Yellowstone is influenced by the same stresses that cause earthquakes.
Earthquakes cannot be predicted yet, but modern surveillance conducted with seismographs (instruments that measure earthquake locations and magnitudes) and Global Positioning S
Felt earthquakes on Mount Hood (Oregon) occur every 2 years on the average.
Volcano eruptions have occurred shortly after earthquakes and they may be linked, but scientists are still debating the topic. Notably, an Andean volcano (Cordon Caulle) began erupting 2 days after the magnitude 9.5 1960 Chile earthquake. 
Sometimes, yes. A few historic large regional earthquakes (>M 6) are considered by scientists to be related to a subsequent eruption or to some type of unrest at a nearby volcano.