Andrew's OK, But May Face Challenges

Morning correspondence with Andrew:

Hi Marc,

I am in Australia this week so don’t know what my house may have experienced but if you copy the co-ordinates of these earthquakes and put into Google Maps, they are all VERY close to Diamond Harbour!

http://www.geonet.org.nz/earthquake/quakes/recent_quakes.html
http://www.christchurchquakemap.co.nz/

You don’t want to be there – with aftershocks every 20 minutes or so, it is horrible. I didn’t sleep at all with the Sept 4 event and its aftershocks. They settle down after a couple of weeks but initially it is horrible. How on earth some experts can say these are aftershocks from the Sept 4 event is beyond me. This is a new event, not an aftershock. It therefore has its own new aftershocks. How do I know it is a new event? Because the Sept 4 event had 4000 aftershocks which decreased rapidly with time and last week there were very few, if any, aftershocks. Then a new event occurred on Feb 22 in a new location – i.e. a new fault line which was not previously known. This fault line seems to be right below Lyttelton, Diamond Harbour etc.

Is an extinct volcano about to blow???!!!! I hope not!!

Andrew

Andrew:

Scary. The epicenter of the 6.3 shock was only about 5.4 km from your house. In addition to the City Center, Lyttelton suffered too. I heard a brief radio report saying Lyttelton ‘looked like it had been bombed’. I don’t know what that means, but it can’t be good.

This pattern of quakes, that are more-or-less aligned with the Greendale fault, with the shallower quakes at the eastern end in the vicinity of Lyttelton, revealed itself as early as October, 2010. Yesterday’s quakes seem consistent with that. In the global picture, calling these February quakes aftershocks of the Sept. 4th quake seems reasonable.

I don’t know whether volcanism is in the immediate future for Christchurch. I suspect not. It takes years for magma to make its way up and the volcanologists should have spotted the magma body a long time ago if it was there. Nevertheless, sitting on the flanks of the Banks Peninsula, with a volcanic past plainly visible in all directions, perhaps a bit of paranoia on the question is understandable. And times change, of course. (The city that really needs to watch out is Auckland. Rangitoto Island in Auckland Harbour formed only about 500 years ago, within Maori storytelling memory, and there’s no reason they couldn’t get another volcano, anytime).

Keeping prayers out for you, and for all of the people of Christchurch, and vicinity. You may be faced with some serious challenges when you return. Friends can help. Let me know; I can make myself available.

Marc