What could be causing hourly bitcoin price spikes? The price spikes every hour, on the 26 minute mark:

https://bitcoinaverage.com/charts.htm#USD-averages-1d

(Although it seems like spikes do not show up for some people/browswers.  Her is what I see: imgur.com/aKYaDvX )
Someone could have programmed a bot to place buy-orders every hour based on a some historical price average, say over the last 24 hours.