After the 8/22 earthquake felt all over the northeast US, cell phones were not working in our area, apparently due to the flood of calls of people checking with their friends. However, landlines worked fine.
While an earthquake is very surprising in the east, this was very minor in the grand scheme of things. What would happen to the telecom network (all modes--landline voice, internet/email, cell phone) if there was a serious event?
I believe on 9/11/2001 telecomm service in the NYC area was disrupted due to the flood of calls.