All earthquake recordings today are recorded digitally by digital seismographs. All the records and stored digitally and any warnings issued by earthquake centres are based on digital information. I don’ t know about you, but my computer hasn’t exactly been ms. perfectly faithful during the last few years.. is it not possible that these computers that are used in earthquake science might break down, freak out or freeze up (back to personifying computers!). So while the early warning systems that are in place in some parts of the world may seem like a good idea, it is theoretically possible that they could just stop working – without warning. What would that leave us with? a lot of money spent for no good.
There are many fault-tolerance techniques that are used to make computers more reliable.
Usually you will have replication, so if one of your computer freeze the other takes over.
However fault-tolerance is quite expensive so the money invested depends on the criticality
of the application. Life-critical application (airplane auto-pilot, rail shifting program)
usually use quite elaborate fault-tolerance and use formal proofs that proves the program
is correct. But you are right… even with all these techniques catastrophee still occur,
a number of planes have crashed because of software bugs.