What type of plate boundary has a lot of seismic activity

Destructive plate boundaries / conservative boundaries, but destructives boundaries are the worse because volcanoes and earthquakes occur here. The collision of the 2 plates create tension and release seismic waves, also because of this the oceanic plate is dragged downwards (subduction) creates a ocean trench, as it sinks it melts and creates magma, this is leeds to volcanoes erupting

I'd have to say the Southern Eurasian plate and the Western part of "our" North American plate (mainly around California) both have a lot of above sea level activity. The most activity below or right at sea level would possibly be the Philippines plate.