Why this wasn't prominently discussed in the media is beyond me.

Yeah would think even purely out of self interest - for a bit of good ol' fear-mongering media hysteria if nothing else

But within 48 hours it was back to CCTV car accidents and delicious titbits of food from the latest restaurant

Following on from what you wrote originally, perhaps the reasoning goes like this:

1. A major 7-8M earthquake in Taiwan at some point in the relatively near future is a mathematical certainty
2. We don't have a way to short-term predict it with any accuracy and false alarms would create panic, logistical nightmares and cost billions in lost production
3. The most cost-effective and stabilising decision would be to downplay the threat of it - even if that includes the suppression of information