Did the earth move for you last night?

This was a question I asked Ann, rather tongue in cheek, after we felt the house roll under us for at least 20-30 seconds. It was obvious from the rolling nature of it, the fact that it was fairly constant and the lack of "shaking" that it was a long way off and of a reasonable depth. We thought it might be around a 6-7 and centered off Fiordland some where. Well we were spot on.

We logged on to the Geological and Nuclear Sciences Website. Initially reported as 6.8 and 5 km deep this was some what revised to 7.8 and 12 km deep although overseas reports vary and apparently there is some data reconciliation to occur between US centres and those in NZ.

For our overseas friends there have been 25 earthquakes in NZ over the last week alone: 8 of these in the last day and all related to the quake of 7.8 west of Tuatapere and ranging from 5.1 - 6.1

So how much grunt did it have: "Magnitude is a quantitative measure and intensity is qualitative. There is roughly a 30-fold increase in seismic energy for each step up in magnitude. A magnitude 5 earthquake releases as much energy as the Hiroshima atomic bomb — the equivalent of 15 kilotons of TNT. A magnitude 6 is equivalent to 30 Hiroshima bombs. Alternatively, a magnitude 7 quake releases about a million times more energy than a magnitude 3 quake."


We have not felt any of the after shocks.

Kids felt it as it woke them. Alana thought it was cool but Samuel was less impressed.