'Out of the blue' landslide in Taiwan

I came across some killer mass-wasting photos via a long email chain
recently. A colleague who was in Taipei at the time indicated that
this event occurred on a dry day and with no corresponding seismic
activity...thus, 'out of the blue'.

Event occurred in April 2010 in vicinity of Keelung City:

http://goo.gl/maps/bc1t