This source isn't saying 100 feet, but it's a considerable amount. I think you might be able to bank on their word.
http://neic.usgs.gov/neis/bulletin/neic_slav_ts.html
Thanks for the link, confirms more of what I said. BTW I am a geologist and understand the discussion presented by the USGS based upon seismic data and common sense. I don't doubt 'a considerable amount' but read the article more carefully and look up the tectonic symbols present and you will see that the USGS looks to the northwest from the epicenter as the line of rupture. Go to southeast you encounter a spreading center plate boundary that the rupture would not have crossed but would at most have generated a strike-slip motion to the southwest-northeast. Pending re-surveying of the land, exact displacement cannot be determined by seismic data alone, so actual displacement at this time is speculation.