Double Earthquake!... and now an 8.8 Mag + Tsunami in Japan

[Chuft-Captain]

At 4:35am this morning (16:35 GMT) a 7.1 magnitude earthquake struck Christchurch, NZ. The epicenter was about 30km west and only 10km deep.
http://www.reuters.com/article/idUSTRE6823Q420100903?loomia_ow=t0:s0:a49:g43:r1:c0.370455:b37059930:z0

Felt like a giant man had picked up the house and shook it like a rag doll.

Amazingly, this quake was very similar magnitude to the Haiti one, but here there have been no confirmed reports of deaths. So far (15.5 hours later) there is still only 2-3 serious injuries, and one *unconfirmed* report of someone dying of a heart attack during the quake. (Although there's a lot of property damage, and some very close calls for some people).
-- One guy's second floor exterior bedroom wall fell off the house taking him with it all the way to the ground. He ended up under bricks with a few scratches and a sore back, but the bed he had been in 5 seconds earlier was crushed by the roof.

Still getting regular aftershocks (largest so far was about 5.7) ... and more to come... they expect that some could even be larger than 5.7 in the next 48 hrs..

CC

[TERRIER]

The quake has made the main news headlines on tv and radio over here, glad to see that the human casualty list seems to be very small.
Hope there's not too much damage to yourself or your property.

[Fenerit]

How do you feel, Chuft? You are injured, your things are damaged? Hope not. I saw that from tv net. I saw houses very distantiated amongs them, this help in prevention of collapsing, because a building which collapse doesn't add forces on other instable buildings.

[Chuft-Captain]

Thanks for the concern,

Everyone OK in my family, just some minor property damage, fallen or damaged chimneys, stereo equipment, ornaments and crockery, broken wine bottles, etc...

Looks like at this stage at least 1/3 of all properties in the city will have some sort of damage, (if not to the structure, then broken items inside), but most serious damage seems to have been to old brick and slate roofed historic buildings in the central city.
In some areas near rivers and estuary there has been liquefaction and some houses have fallen off their foundations.
Older brick structures have definitely come off worse than other more modern houses. A lot of brick fences are over, while wooden fences on the next property along may be undamaged.

It's really a miracle that no-one was killed, but that is partly due to the fact that we have very strict building codes in New Zealand precisely because we live on the edge of 2 major tectonic plates, but mostly I think because of the time of day that it occurred... everyone was tucked up in their beds. ... If it had happened a few hours earlier on Friday night then everyone would have still been out in town in the bars and clubs! ... could have been a very different outcome. [EDIT: Just read in the newspaper that one man died of a suspected heart attack during the quake.]

The real tragedy is that later the same day, sadly, 9 people were killed in a plane crash on our west coast.
This barely featured in the news because of the quake. On any other day this would have been the leading news item.

CC

[Chuft-Captain]

Just an update...

Here's an interview with the guy who fell out of his bedroom that I mentioned in the first post: http://www.youtube.com/watch?v=EWbzuli5jbQ

So far there's been nearly 300 after-shocks, about a dozen or so have been > 5.0 in magnitude. There was a particularly close and shallow 5.1 at 7:49am today which shook the house quite badly and took out the power again.
Since then there have been another 18-19 smaller ones today: http://www.geonet.org.nz/earthquake/quakes/recent_quakes.html

The following picture is worth a thousand words... (source: http://www.christchurchquakemap.co.nz )
(... this is all in the last 4 days):

quakemap-2010-09-04.jpg

The scientists are saying that after a large quake it's common to have at least 1 after-shock of about 1 magnitude less than the main quake. (This would be a 6.0 - 6.1 if it happened.)

Everyone is hoping this does not eventuate as that would certainly bring down many already weakened buildings. I'm hoping that the numerous smaller ones are dissipating most of remaining tension and we won't get another big one. A 6-mag is a serious enough earthquake in it's own right, let alone when there's already damage.

CC

[Chuft-Captain]

Some aerial shots of the fault trace outside of Christchurch...

Click for full-size...

This farmer's hedge won't be so easy to trim in future:


An irrigation canal is breached:


A road is moved by 1/2 it's width (and uplifted):

More here:
http://www.teara.govt.nz/en/historic-earthquakes/page-12
http://www.geonet.org.nz/news/sep-2010- ... ponse.html

[t00fri]

Wow!

No wonder I am afraid of quakes .

Worst "vision": I definitely hate blocks of concrete falling on my face at night...Despite extensive travelling along the "Ring of Fire" over many years (Chile, Peru, Mexico, California, Alaska, Japan, Sumatra, ...) I have only experienced a barely perceptible 15 second quake in Japan during a 2 months stay .

Hard to "enjoy" quakes in Germany (but they happen, actually).

Fridger

[Chuft-Captain]

Be afraid...be very afraid! --- http://www.christchurchquakemap.co.nz/

[Fenerit]

To return to the questions about the seismic prevention, seem to me that yours stardards are good, whether where I live an earthquake of 2000 times less powerful got such results:

http://www.google.it/images?client=firefox-a&rls=org.mozilla:en-US:official&channel=s&hl=it&q=terremoto+Aquila&um=1&ie=UTF-8&source=univ&ei=DyOQTKT6J-aIOPOj8aQN&sa=X&oi=image_result_group&ct=title&resnum=6&ved=0CD4QsAQwBQ&biw=1024&bih=580

[bh]

Waiting for news from Chuft.

[abramson]

I hope you are well, Chuft...

[Chuft-Captain]

Hi Bob, Guillermo,

Thanks for your enquiries. I am still alive, and all my family members are also OK. (But many families in our city are not so lucky today... 65 confirmed dead today, and estimated several hundred still missing or trapped at sundown. Unfortunately it is also raining now which may hamper rescue efforts.

You have probably seen more reports than me at this point, as power was only restored to our suburb at 9pm tonight. Still catching up on the TV news via BBC World (It's 4:40 am, but can't sleep anyway due to regular (almost continuous) aftershocks (in fact there was another one just now exactly at the moment that I typed the word "aftershock"! )

What I can tell you is that this quake was much more violent here than the 7.1mag in Sept, largely because the epicentre was virtually within the city itself, and very shallow - 10km from our CBD and only 5km deep (7.1 mag on Sep 4 was 40km away and 12km deep).
We had accelerations up to 1.5 x G and one guy told me he saw his car flying in the air 1m above the ground.

Unfortunately this quake also happened at the worst possible time (lunchtime on a workday), so there were many people in the central city where most of our older brick buildings are. Many of those, including some more modern buildings have now collapsed.

Expecting that today will only bring more sad news of devastation and death.

CC

[Chuft-Captain]

Latest Rolling Updates: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10707997

Damage and deaths: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10708101

Aftershocks: http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10708092

Photos: http://www.nzherald.co.nz/nz/news/image.cfm?c_id=1&gal_objectid=10707996&gallery_id=116912#7380552

Aerial Photos: http://www.nzherald.co.nz/nz/news/image.cfm?c_id=1&gal_cid=1&gallery_id=116918#7380591

Quake Map Animation: http://www.christchurchquakemap.co.nz

[bh]

Phew! Glad you're okay Chuft... been watching BBC... looks horrendous... keep yerself safe.

[Fenerit]

I'm very happy that you and your parents are still alive, because from TV net the devastations are catastrophics, with flooding, too.

[t00fri]

Hey CC,

good to know you're safe! No wonder that I am afraid of quakes...

Fridger

[Chuft-Captain]

Still here...

Some info about the quake at the geonet site: http://www.geonet.org.nz/news/feb-2011-christchurch-badly-damaged-by-magnitude-6-3-earthquake.html

Note that the maximum shaking was 2.2 x G, the highest ever recorded for any earthquake in NZ (almost twice the maximum of 1.25 x G recorded for the magnitude 7.1 of Sept 4th)

CC

[MiR]

Terrible news was this.
I wish you and your people of New Zealand all the best for a new beginning.
I hope the help is sufficient...

Michael

[t00fri]

Still here...

Some info about the quake at the geonet site: http://www.geonet.org.nz/news/feb-2011-christchurch-badly-damaged-by-magnitude-6-3-earthquake.html

Note that the maximum shaking was 2.2 x G, the highest ever recorded for any earthquake in NZ (almost twice the maximum of 1.25 x G recorded for the magnitude 7.1 of Sept 4th)

CC

The devastating effect of this "record G-impact" in case of your 6.3 mag quake, illustrates dramatically that the magnitude reached on the Richter scale is just half the story. The G-impact should be quoted always together with the magnitude value of a quake. This should also make people understand better whether high destruction in a "low" magnitude event was due to "high G-impact" or rather due to corruption in the house building industry!

Fridger

[Chuft-Captain]

Still here...

Some info about the quake at the geonet site: http://www.geonet.org.nz/news/feb-2011-christchurch-badly-damaged-by-magnitude-6-3-earthquake.html

Note that the maximum shaking was 2.2 x G, the highest ever recorded for any earthquake in NZ (almost twice the maximum of 1.25 x G recorded for the magnitude 7.1 of Sept 4th)

CC

The devastating effect of this "record G-impact" in case of your 6.3 mag quake, illustrates dramatically that the magnitude reached on the Richter scale is just half the story. The G-impact should be quoted always together with the magnitude value of a quake. This should also make people understand better whether high destruction in a "low" magnitude event was due to "high G-impact" or rather due to corruption in the house building industry!

Fridger

In fact, there are already 2 different scales used in New Zealand. The older and more well known one is the Richter scale, which measures the amount of energy in a quake, but in modern times the Modified Mercalli intensity scale is also used, which is a better measure of how that energy is released and it's effects on people and structures on the surface. Obviously these effects will be greater for shallower quakes, and this one, at 5km, was a very shallow quake.
See here for details: http://www.geonet.org.nz/earthquake/geonet-modified-mercalli-intensity-scale.html
I believe last weeks quake was rated as a 9 on the 12-step Mercali Scale.

The current official death-toll as of today is 161, expected to rise to as much as 240.

Current estimates are that up to 60% of buildings in our CBD are beyond repair and will have to be demolished in the near future (if they haven't already collapsed).