What is the relationship between volcanoes, earthquakes, and plate-tectonics?
You could also include tsunamis, Arnel. LOL. The shifting of tectonic plates causes earthquakes, and earthquakes and/or tremors of all magnitudes contribute to volcanic eruptions. To include my addition, these same tectonic shifts/quakes serve as the trigger(epicenter) for tsunamis, even the Sri Lanka one.
Plate-tectonics cause Earthquakes on subduction zones. Those are on convergent bounderies, as one plate goes under another one. The earth buckles up, and like a rubber band storing energy, stretches and twists until it SNAPS back together in an Earthquake. Volcanoes are tricky, we arent sure if eruptions cause earthquakes or earthquakes trigger eruptions, but oen thing is for sure, there there are more and more earthquakes getting bigger and bigger its about to explode.