According to this site their seems to be a long history of seismic activity on the island. 295 quakes in the last year. Compare this with 2 for Cuba and zero for Jamaica that makes me think the island is sitting on or near an active fault line.
http://earthquaketrack.com/p/dominican-republic/recent
I assume this means the island will someday experience a quake like what was seen in Haiti some years back. Let's all pray it's hundreds of years away...
As a side note I was in my hotel room in Santiago about a year ago and felt several strong shakes but did not pay much attention to them not thinking/knowing about the potential for a major quake. Moving forward any signs of tremors and I will be calmly looking for relative safety...