Aftershocks and Rumors of Aftershocks
Wednesday May 14, 2008
In the wake of the Chengdu earthquake earlier this week, the Chinese Seismological Bureau had to issue a statement yesterday telling people to ignore rumors of a supposed aftershock prediction. There was no prediction, because aftershocks can't be predicted any more than mainshocks can. Aftershocks are more predictable than regular earthquakes only in this respect: aftershocks of a particular earthquake, considered as a whole, can be described by three numerical laws. That underlies the US Geological Survey's daily 24-hour aftershock forecasts for California.
There is a line of thought among earthquake researchers that maybe, if you back away far enough, the earthquakes in a large tectonic province or even the whole planet can be analyzed as if they were a great self-generating aftershock series. That underlies some interesting basic research tied to earthquake prediction, but it doesn't provide the planners and responders of today any useful information.
Comments
Last night, 5/19, all state-sponsored media warned that there would be a large probability of aftershocks. I returned to my apartment community to find that every single apartment had it’s lights off — had been evacuated by its tennants. Was this a socially-responsible or in anyway legitimate warning?
I don’t know, and I hope someone more knowledgeable will speak up.