✔ 最佳答案
Mt St Helen's is on the tectonic boundary between the Juan de Fuca and North American plates. Tectonic boundaries account for a large percentage of both volcanoes and earthquakes.
It is still an active volcano and any eruptions are quite difficult to predict though it can be done to some degree of accuracy especially with such a well monitored volcano. Earthquakes are much more unpredictable and the likelihood of one being predicted is low.
參考: Geography student at the University of Hull and have studied mt. st Helen's many, many times