I'd retest for everything, standard water tests you would do to commission a new well. You never know if a seismic event might open new cracks, change the aquifer the water runs through, etc.
We have a well up in Keene. We brought a sample to a water testing outfit when the well was new in 2004, before we drank any of the water. It tested out great: no germs, few minerals, only slightly hard. And it tastes great. We use it straight from the well, unfiltered and untreated, and it's been fine. We haven't restested it, but it's 500' in solid anorthosite, so I doubt it changes much over time.
We're 7 miles away and 1100' higher than you, so I don't think the Etown earthquake would affect our well. But if you were right on top of the epicenter, and really felt a lot of shaking, it might be a good idea to test your water.
Tom