Volcanoes can be dangerous, but when you look at an Earthquake many things can happen at once other than Volcanoes that only have one function and are easily predicted, they also stay dormant for periods of times leaving them harmless. An earthquake is when two sections of earth slide past each other, this can create a fault line which is a giant gap in the group that could possible form under cities and destroy buildings by bringing them under ground and killing possibly hundreds in the process. During an Earthquake in the sea a tsunami could happen and they can go from unnoticeable to devastating, they can destroy boats, buildings, bridges, cars, trees, telephone lines, power lines, and anything else in its way. Just an earthquake itself can destroy and building and bring down bridges depending on the value of it. In 1556 the deadliest earthquake happened in China killing about 830,000 people who lived in caves. Scientist also think that volcanic eruptions and earthquakes are related but some think not, only after a volcanic eruption on November 29, 1975 a small earth quaked happened but scientist are still unsure if they were related. Land slides can also happen, either clumps of dirt and mud can push aside houses and cars or deadly boulders tumbling down with it. These are my reasons that an Earthquake is more powerful than a Volcanic Eruption.

Sources:

http://earthquake.usgs.gov/learn/facts.php

http://www.sms-tsunami-warning.com/pages/tsunami-effects#VMERbFWJOuy