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The event occurred at 0611UTC, and for 2.5 hours(!) the connectivity from SLAC to NNREN was maintained quite well, it seems.
I agree it is very interesting/curious that the connectivity appeared to continue working for 2.5 hours, and then died. One would need to talk to the net and host admins. There are many possibilities e.g. maybe the network continued to work but a UPS on the host ran out of battery power, or the backup generator ran out of fuel, or people deliberately shut down power.
It is interesting that the connectivity continued for an hour or so after the shock wave. Caltech points out that this could be important for projects measuring the impact of the initial shockwave.
There is a second gap in the www.most.gov.np on 25 April from 1309-1939UTC, for which a similar question arises about the gap source.
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