EWR currently has a ground stop in place due to 'other'. Many inbound planes are circling and at least one BOS-EWR is in the process of diverting back to BOS.

There was an earthquake (4.8) in New Jersey a little while ago which is presumably causing this. (I believe inspections have to be performed to the runways following an event like this).

Departures are occurring however, so I figure arrivals may begin again soon.