I'm sure the data is coming in from multiple sources and being stored on high capacity tape archives or something, if it's not just being thrown away at some point after analysis is complete.
My guess is they have a cabinet / 42U worth of HDD arrays, by the numbers they need ~ 176Gbps write bandwidth which is totally possible even in half a cabinet.
400TB worth of SSDs @ 176Gbps write bandwidth is also very possible, would be ~ 4U expect but extremely expensive.