I strongly suspect this is not due to an outage in the network, but rather intentional. Some years ago I worked on a project for a Japanese mobile operator to implement a system that prevents "normal" mobile phones from making calls to avoid overloading the network. When activated, only emergency services (fire fighters, police, medical, ...) are allowed to call. At regular intervals, a batch of the "civilian" phones are allowed too for a while, then a different batch, etc, so everyone gets its chance to call if they wait long enough.
The system was a government requirement for events such as yesterday's quake, but I can't confirm all phone disturbances reported were/are due to it.
Technically, it relies on a bitpattern called "accessClasssNBarred".
The system was a government requirement for events such as yesterday's quake, but I can't confirm all phone disturbances reported were/are due to it.
Technically, it relies on a bitpattern called "accessClasssNBarred".