The network they were showing on Nova seems to be under development and seems very extensive. So, likely speed of light. Istanbul Turkey has had an early warning system for quite a while: I was shown a little on it in 2006 when I visted Kandilli Obervatory. They can also very quickly show ground motions by neighborhoods very quickly (or something like that).

Turkey science is definitely at a high level! But in some cases their geophysicists lack geology training on some level.
Chris