IF it is legitimate traffic, no worries. I've had this happen many times when a certain page of mine gets a bit of attention. Traffic may double or more. The first time it happened I sent an email to Adsense to let them know and they said everything was fine. I didn't inform them the other times and nothing has happened to me. IF it is NOT legitimate traffic, then there is cause for concern, but I'm assuming you mean legitimate traffic.
i had a huge surge of traffic when my site was only a few months old from being mentioned on the radio, then another huge surge after that radio-host's podcast was released about a month later.. Then another huge surge about 6 months later from being on the front-page of Digg, then another surge about a year later from being on Gizmodo - all were legitimate traffic and caused no issues ..
There is no need to worry as long as the traffic is legitimate and you need not inform the google about it.
Sudden increase in traffic will not jeopardize your account in any way. Google don't go about monitoring the traffic for you. Your concern should be on the ctr and conversion. As long as you play according to their rules and tos, there's nothing to worry about.
Don't ever promote your sites in adult forums which will give you instant surge in traffic but Google will tag your account for smart pricing which means even if you get 100 clicks your earnings will be less than $1