Earthquake in NZ

Scary times down there. I lived in Hamilton for 5 years and didn't feel a single earthquake.

Wellington is pretty crazy from a fault perspective. Scary place to live, considering the Quay, Beehive, etc., were all under water ~ 100 years ago until a quake pushed the land up out of the water.

 

So it would seem that Shakin was shakin'.



Seriously, hope you're ok.

 

Wow, is it really 2 years since Christchurch?

Anyway, glad you're ok.

 

I experienced my first earthquake ever about 2 years ago. Fortunately it was so minor that it was barely noticeable. I've often thought about how much it must stink to get caught in a bigger one though...ugh.. glad you're ok, stay safe

 

Wow. That must have been a few moments of utter terror. Give me the cold, wet hills of Northern England any day of the week!

 

I'm not a seismologist. But, as geologist I know a bit about faults and quakes.

When the earth scientists say that you may be due for a large quake, that's based upon research of past earthquakes. Using various dating techniques, the scientists can generate a record of time intervals between large quakes on a given fault system and then extrapolate that to give an idea of future risk.
It's not very precise because the intervals can be hundreds or even thousands of years. It is useful to the extent that building codes can be updated to reflect the risk of that event.
For example, if a fault system shows large breaks on an average of 500 years and it's been 800 since the last large quake, then you can figure that pressure has been building up for all that time and may be ready for a release sooner rather than later.

 

Oh...if the land that these towns and suburbs was uplifted from the ocean, then it can also go back down.

However, the overall fault movement is more likely upwards. Seattle, Washington also has areas that were uplifted from Puget Sound.

120 years isn't very much time geologically speaking and it seems unlikely that a great deal of stress has built up in that relatively short timeframe.

The Alpine Fault of NZ has quite a record of very large quakes.

 

Those of us who live near plate boundaries have to be ready for earthquakes. Here's a link to the details of the earthquake.

 

This particular earthquake was predominantly lateral movement, though, which is somewhat atypical of plate boundaries in that region. North of NZ, the Pacific Plate is being thrust toward the west, under the Australian Plate. South of NZ, the direction is reversed, with the Australian plate being thrust eastward under the Pacific Plate. So the islands of New Zealand seem to be situated in a transform zone where lateral movement accommodates the change in stress orientation indicated by the reversal of thrusting.

Here's a link to the moment tensor diagram (beach ball) indicating strike-slip movement at the hypocenter.

That's all I got.