Since the big Kaikoura earthquake last week there have already been well over 5000 aftershocks, all logged and recorded by GeoNet, the earthquake and volcano monitoring system that sends alerts to smartphones, and is made available on the web. So how does the movement of the earth’s crust get recorded and then broadcast as an alert to your phone within seconds? To discover how the information moves from a fault line in the South Island to your digital device we headed out with some of the team from GeoNet.