This is the 4th prediction from Shan for a M8.5 to 9 in the general Sumatra region. The first one was correct on magnitude and time, and a couple rupture lengths off on location. The subsequent predictions failed. Still, the odds of getting the first one that close in a 1 week window were relatively long.
The prediction method makes no sense to me, so it is results of predictions that will establish credibility or lack thereof. There have been enough predictions over the years by Shan on this page that they could be evaluated...I can't evaluate a bunch of M5 earthquakes in areas where they are reasonably common.....needs Roger-style evaluation.
Chris