7.0 earthquake hits Christchurch, New Zealand

[Astronuc]

It is important to pay attention to activity in the region encompassing Vanuatu, Fiji, Tonga, Kermadec Islands as well as NZ. They are part of the same system.

Seismic activity around Christchurch. The Canterbury area is an outlier for big ones.
http://neic.usgs.gov/neis/bulletin/neic_b0001iiu_l.html
http://neic.usgs.gov/neis/bulletin/neic_b0001iiu_h.html

Also pay attention to changes under Akaroa and Lyttelton.

The activity under Lyttelton is interesting. It stopped abruptly. Correction: it's filtered for > 4mag

         UTC DATE-TIME        LAT    LON
MAG     y/ m/d   h: m:s       deg    deg    DEPTH km    
4.2  2011/02/22 17:00:19   -43.613 172.814   8.4  
4.0  2011/02/22 14:30:13   -43.634 172.819  13.4  
4.3  2011/02/22 14:04:36   -43.614 172.875  10.0  
4.5  2011/02/22 11:02:16   -43.548 172.779   5.0  
4.8  2011/02/22 08:21:06   -43.599 172.560   6.9  
4.5  2011/02/22 06:43:30   -43.593 172.859   5.0  
4.4  2011/02/22 06:28:31   -43.590 172.710   5.0  
4.3  2011/02/22 05:59:35   -43.640 172.770   5.0  
4.1  2011/02/22 04:19:05   -43.600 172.750  15.0  
4.4  2011/02/22 03:04:09   -43.570 172.650  12.0  
5.5  2011/02/22 01:50:29   -43.588 172.734   9.6  
5.6  2011/02/22 00:04:18   -43.580 172.798   6.7  
6.3  2011/02/21 23:51:43   -43.600 172.710   5.0

 

[nismaratwork]

Wrong theory. The Alpine fault where the plates actually grind past each other is still waiting to go (about once every 600 years). These are just lateral faults that run all the way up the eastern coastline. The alpine would be 8+. And about as damaging as current quakes here, because it would be over 100km away. But bad for other cities and towns right in the path.

Many cities have rebuilt quite well out of quakes, so the 20 year view is more optimistic. At least now we can say that two of our big local faults have gone and it should take another 20,000 years or so for them to reload. It seems unlikely there can be more lurking so close to town. But hopefully we will be doing full seismic surveys to discover that.

I admit, I was reaching... you're too smart for your own good and comfort!

Again, I'm very glad you and your's well.

 

[fuzzyfelt]

Good to hear apeiron, apeiron's family and cats, and Dadface's family are safe.

 

[rhody]

Wow, glad to hear that you survived (with just a scare) and everyone in your family including your pets are safe, I lived through 2 quakes in San Diego in the late 70's and early 80's. They are disconcerting and frightening to say the least. Has the damage affected your ability to get to and from work, and your work place, at least for the short term ?

Rhody...

 

[hypatia]

apeiron, good to hear everyone is ok.

 

[apeiron]

Has the damage affected your ability to get to and from work, and your work place, at least for the short term ?

My workplace is semi-collapsed and will be demolished I'm sure. Ironically, we were due to move into a brand new building next week. That survives but with many windows gone and other damage. Besides, central city will be out of bounds for a month I would say.

We have a 20 story hotel that is leaning into a hole that opened up under a corner. That has to come down somehow. Whole city blocks will be bulldozed.

But I write for the city paper. And we got an edition out the next morning. You'd be surprised at how people can cope. Especially with all the help that comes in from outside.

 

[Astronuc]

Recovery is still ongoing, and it will take along time.

http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10708858
http://www.starcanterbury.co.nz/local/news/christchurch-earthquake-death-toll-rises-123-more-/3942201/

 

[lisab]

My workplace is semi-collapsed and will be demolished I'm sure. Ironically, we were due to move into a brand new building next week. That survives but with many windows gone and other damage. Besides, central city will be out of bounds for a month I would say.

We have a 20 story hotel that is leaning into a hole that opened up under a corner. That has to come down somehow. Whole city blocks will be bulldozed.

But I write for the city paper. And we got an edition out the next morning. You'd be surprised at how people can cope. Especially with all the help that comes in from outside.

Wow, I can't even imagine what that must be like! It could take many years to recover, from the sounds of it.

 

[Astronuc]

I finally got word from a relative. Ironically, their house was being inspected by a representative from the Earthquake Commission when the earthquake struck. They live near Lyttleton. Needless to say, they have more damage.

They are visiting family up north and will be back early next week to help with ongoing efforts.


Someone snapped this picture seconds after the earthquake
http://www.redditpics.com/christchurch-panorama-seconds-after-earthquake,11249/

At least 1/3, and maybe up to 2/3, of the buildings in the central business district are damaged.
http://www.3news.co.nz/Christchurchs-heart-ripped-to-bits/tabid/369/articleID/200008/Default.aspx



A close friend has family in CC. Everyone is OK.

 

[fuzzyfelt]

Good to hear your rellatives and your friend's rellatives are ok. I'm sorry to hear of all the damage, of course.

 

[rhody]

aperion,

My workplace is semi-collapsed and will be demolished I'm sure. Ironically, we were due to move into a brand new building next week. That survives but with many windows gone and other damage. Besides, central city will be out of bounds for a month I would say.

I just looked at a few of Astronuc's links, the heart of the quake was essentially right under the center of downtown ? Holy ..., it sounds like you sort of lucked out, as you mention moving to a brand new work place next week. I am sure it is very unsettling. I only speak for myself, but you seem to be holding up remarkably well considering all you and you family and community have been through. I don't know what else to say except that in print on PF you seem remarkably calm and composed, if it were me, I assure you that would not be the case.

Rhody...

 

[Astronuc]

I heard one official mention the cost of rebuilding the infrastructure being as much as $30 billion.

There is a picture that shows the distribution of earthquakes before and since Feb 22. Clearly the earthquake occurences have been shifting eastward (and westward) during the last several months.
http://www.geonet.org.nz/news/feb-2011-christchurch-badly-damaged-by-magnitude-6-3-earthquake.html

The acceleration at one station was revised to 2.2g, which is a very significant acceleration.

 

[apeiron]

This is an excellent graphic illustrating the location of the two quakes (the second in red is clearly right under the town) and just how many aftershocks there have been.

http://www.geonet.org.nz/var/storage/images/media/images/news/2011/lyttelton/57171-1-eng-GB/Lyttelton.jpg

 

[Astronuc]

If one checks Paul Nicholls's earthquake map, one sees in the two hours following the mag 6.3, there were two others at mag 5.7 and 5.9, punctuated by several in the 3 - <5 range.
6.3M, depth: 5km 12:51
4.9M, depth: 5km 12:56
5.7M, depth: 7km 13:04
4.2M, depth: 9km 13:21
4.4M, depth: 7km 13:23
4.2M, depth: 9km 13:31
4.5M, depth: 5km 13:46
4.5M, depth: 5km 14:15
4.5M, depth: 4km 14:20
3.4M, depth: 5km 14:30
3.3M, depth: 5km 14:37
4.0M, depth: 8km 14:39
5.9M, depth: 7km 14:50

And there have been many more since.

The liquefaction of the ground was considerable more severe with the Lyttelton earthquake than with the Darfield quake which was further away and deeper.

 

[nismaratwork]

This is an excellent graphic illustrating the location of the two quakes (the second in red is clearly right under the town) and just how many aftershocks there have been.

http://www.geonet.org.nz/var/storage/images/media/images/news/2011/lyttelton/57171-1-eng-GB/Lyttelton.jpg

Stay strong apeiron, and again... I'm really glad that you and dadface are alive and whole, with families in similar condition.

 

[rhody]

Astronuc, aperion,

I am no geologist or expert in seismology, however, the thumbnail below taken from the links you both provided reminds me of a zipper, a buried one that is slowly rising to the surface as it heads toward the ocean.

Rhody...

 

[nismaratwork]

Astronuc, aperion,

I am no geologist or expert in seismology, however, the thumbnail below taken from the links you both provided reminds me of a zipper, a buried one that is slowly rising to the surface as it heads toward the ocean.

Rhody...

Make that a sticky zipper, and I think you're closer to the truth than you may know!

 

[Astronuc]

Astronuc, aperion,

I am no geologist or expert in seismology, however, the thumbnail below taken from the links you both provided reminds me of a zipper, a buried one that is slowly rising to the surface as it heads toward the ocean.

Rhody...

There appear to be a series of east-west faults, which are a consequence of the those two old (ostensibly extinct) volcanos and the mountains. The Canterbury plains are alluvial deposits having been deposited from the erosion of the mountains to the west.

I think they will have to rethink the seismic hazard in that area.

Some of the day recorded.

 

[nismaratwork]

There appear to be a series of east-west faults, which are a consequence of the those two old (ostensibly extinct) volcanos and the mountains. The Canterbury plains are alluvial deposits having been deposited from the erosion of the mountains to the west.

I think they will have to rethink the seismic hazard in that area.

Some of the day recorded.

When you say things like "ostensibly extinct", you give me agita!

Kidding aside, thanks for an excellent explanation, and... liquifaction is not something you can defend against AFAIK. You can put a building on rockers or springs. make it bend like a willow, but if the foundation goes... game over. You may be able to prevent catastrophic collapse (NZ versus Haiti), but the structure will still need to be destroyed and rebuilt.

I feel terrible for (and I say this affectionately) all Kiwis, feathered and mammalian. NZ seems like such a peaceful and welcoming place...

 

[rhody]

There appear to be a series of east-west faults, which are a consequence of the those two old (ostensibly extinct) volcanos and the mountains. The Canterbury plains are alluvial deposits having been deposited from the erosion of the mountains to the west.

I think they will have to rethink the seismic hazard in that area.

Some of the day recorded.

Astronuc,

That was absolutely horrifying to watch, I only could watch about 2/3rds of the first video, at about 1:30 or so a woman in a black dress with head injuries was being led away. I found out later she lost her brother who was sitting in a car next to her, he pushed her away and saved her life. The video news story was so sad. it all seems so surreal.

Rhody...

 

[Astronuc]

When you say things like "ostensibly extinct", you give me agita!

Kidding aside, thanks for an excellent explanation, and... liquifaction is not something you can defend against AFAIK. You can put a building on rockers or springs. make it bend like a willow, but if the foundation goes... game over. You may be able to prevent catastrophic collapse (NZ versus Haiti), but the structure will still need to be destroyed and rebuilt.

The hazard maps apparently did not predict the peak accelerations up to 2.2g, and certainly not in the Christchurch area. What happened was unexpected. I think seismologists didn't expect something like 6 or above just SE of Christchurch.

The experts will have to revise their understanding of the dynamics.

The liquefaction has to do with the water in the soil under Christchurch which sits between two rivers beside a bay, and has at least one stream running through it, and the fact that the earthquakes were so strong.

I feel terrible for (and I say this affectionately) all Kiwis, feathered and mammalian. NZ seems like such a peaceful and welcoming place...

It's going to be difficult for a lot of folks for quite some time. An article in the Herald indicated that some might leave the area or the country permanently.

 

[Astronuc]

Astronuc,

That was absolutely horrifying to watch, I only could watch about 2/3rds of the first video, at about 1:30 or so a woman in a black dress with head injuries was being led away. I found out later she lost her brother who was sitting in a car next to her, he pushed her away and saved her life. The video news story was so sad. it all seems so surreal.

Rhody...

There's many heartbreaking stories, but some good ones too.

Ahsei "Ace" Sopoaga tried to save the brother of that woman.
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10709041

The brother who saved his sister was Jaime Gilbert.
http://www.3news.co.nz/Young-father...ister/tabid/309/articleID/199985/Default.aspx

And this story
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10709040

 

[nismaratwork]

The hazard maps apparently did not predict the peak accelerations up to 2.2g, and certainly not in the Christchurch area. What happened was unexpected. I think seismologists didn't expect something like 6 or above just SE of Christchurch.

The experts will have to revise their understanding of the dynamics.

The liquefaction has to do with the water in the soil under Christchurch which sits between two rivers beside a bay, and has at least one stream running through it, and the fact that the earthquakes were so strong.

It's going to be difficult for a lot of folks for quite some time. An article in the Herald indicated that some might leave the area or the country permanently.

Thank you for this information, and the links... I really can only say... I'm so sorry for the people of NZ.

 

[Dadface]

Stay strong apeiron, and again... I'm really glad that you and dadface are alive and whole, with families in similar condition.

Thanks people for sending your good wishes.Just to clarify something it is one of my sons and his family who live in Christchurch,I live in the UK.
In their area they had a lot of mud rising due to liquefaction but they are gradually getting the place cleaned up.I think one of the biggest problems is the anxiety caused by the continuing aftershocks.Many people are finding it difficult to get a good nights sleep.Whilst the clear up continues my grand children have been sent to stay with their Kiwi grandmother in Hokitika on the west coast.She runs a pub so things are not all bad.

 

[nismaratwork]

Thanks people for sending your good wishes.Just to clarify something it is one of my sons and his family who live in Christchurch,I live in the UK.
In their area they had a lot of mud rising due to liquefaction but they are gradually getting the place cleaned up.I think one of the biggest problems is the anxiety caused by the continuing aftershocks.Many people are finding it difficult to get a good nights sleep.Whilst the clear up continues my grand children have been sent to stay with their Kiwi grandmother in Hokitika on the west coast.She runs a pub so things are not all bad.

Wow, I'm glad your sons and families are safe; defiitely time to bite the neck off a bottle!

 

[Astronuc]

Rolling boulders from a hill

http://www.nzherald.co.nz/nz/news/video.cfm?c_id=1&gal_objectid=10709223&gallery_id=117013

These folk have remarkable sense of humor. Luckily no one was killed, although one man was killed elsewhere when debris fell on him while helping another person.


Another site tracking the quakes - http://quake.crowe.co.nz/

 

[apeiron]

Spent most of the day touring quake-struck bits of town and at grassroots reconstruction meetings.

Current repair bill for the two quakes is said to be NZ$20b, of which about NZ$12b is covered by international reinsurance . We have a somewhat unique scheme for national disaster insurance here.

On the zipper hypothesis, it seems the first quake was actually four smaller faults that connected up. And this one is not directly connected. So fits a story where the region is riddled with smallish mag 5 and 6 faults. Over a 100,000 years, they would probably become aligned to make a longer big one (of which there are at least a half dozen known further north).

I was in the roughest part of town (our nearest to a ghetto) for much of the morning, and there was a party atmosphere with church sausage sizzles, more bread and fruit than anyone could eat. There is certainly some burglaries going on, but no big deal.

Again the place has to be given an A+ for resilience. There are search and rescue teams from a dozen other countries and they all say it is the best organised operation they have ever seen (well, September 4 did give us plenty of practice of course).

Yet still, a huge and long effort ahead to get back to normal. No illusions there.

 

[nismaratwork]

Spent most of the day touring quake-struck bits of town and at grassroots reconstruction meetings.

Current repair bill for the two quakes is said to be NZ$20b, of which about NZ$12b is covered by international reinsurance . We have a somewhat unique scheme for national disaster insurance here.

On the zipper hypothesis, it seems the first quake was actually four smaller faults that connected up. And this one is not directly connected. So fits a story where the region is riddled with smallish mag 5 and 6 faults. Over a 100,000 years, they would probably become aligned to make a longer big one (of which there are at least a half dozen known further north).

I was in the roughest part of town (our nearest to a ghetto) for much of the morning, and there was a party atmosphere with church sausage sizzles, more bread and fruit than anyone could eat. There is certainly some burglaries going on, but no big deal.

Again the place has to be given an A+ for resilience. There are search and rescue teams from a dozen other countries and they all say it is the best organised operation they have ever seen (well, September 4 did give us plenty of practice of course).

Yet still, a huge and long effort ahead to get back to normal. No illusions there.

No illusions... maybe that's why you plan so well.

 

[Astronuc]

Aftershocks are still continuing. There was a mag 4.8 near the coast under Sumner.

Recovery operations continue and planning for rebuilding is contingent upon understanding the risk for similar or stronger quakes.

Some discussions:

http://www.asce.org/Disaster-Preparedness-and-Response/Biggs-New-Zealand-Earthquake-Diary.aspx

the Feb. 22 aftershock was twice the design level earthquake. Given that, there is no surprise there were failures! The public response is, why didn't officials demand demolition or full strengthening? Officials did what was historically correct, but this aftershock did not follow the pattern.

This is often the case.

Darfield Quake - http://db.nzsee.org.nz:8080/web/lfe-darfield-2010/home

Christchurch/Lyttelton Quake - http://db.nzsee.org.nz:8080/en/web/chch_2011/home

 

[apeiron]

The Christchurch experience shows what could happen in a lot of places. Here is Portland sounding worried.

http://www.oregonlive.com/environment/index.ssf/2011/02/comparing_portlands_quake_risk.html

Geologists have located three shallow faults that cut beneath the most populated parts of Portland. The largest, the Portland Hills Fault, may pose the greatest risk. It stretches from Oregon City to Scappoose. Corvallis and Seattle also straddle active crustal faults.

Yeats says New Zealand has some of the most progressive building codes in the world and is better prepared for earthquakes than most U.S. cities. Schools in Christchurch appear to have stood up well. Many Oregon schools would not. More than half are at a high risk of collapse from a quake, according to a 2007 report by the Oregon Department of Geology and Mineral Industries.

And then...

Disaster preparedness in Oregon has largely focused on a different kind of earthquakes: those from the collision of massive sections of the Earth's crust, called tectonic plates. From Northern California to British Columbia, an ocean-spanning slab called the Juan de Fuca Plate is plunging beneath the North American plate. In a complete rupture across this Cascadia subduction zone, geologists expect magnitude-9 ground-shaking to persist for several minutes across much of Oregon and Washington. They rupture about once every 450 years.

 

[nismaratwork]

The Christchurch experience shows what could happen in a lot of places. Here is Portland sounding worried.

http://www.oregonlive.com/environment/index.ssf/2011/02/comparing_portlands_quake_risk.html



And then...

Damn it!


Why are some of the best places to live so seismically unstable?? I love Oregon... especially Portland... and hazelnuts... and Tilamook cheddar...

 

[Astronuc]

Christchurch areas to be abandoned
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10710770

Many places along the Pacific coast are in danger of earthquakes or tsunamis, and in some cases volcanoes. The coast is a nice place to live if one likes the ocean and beaches, but it comes with risk.

There is a particular feature near Fiji/Tonga that if it thruts up or down could cause a significant tsunami that would devastate many coastal cities from Australia, NZ and Chile, up to Japan, Russia, Alaska, Canada and the US.

 

[nismaratwork]

Christchurch areas to be abandoned
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10710770

Many places along the Pacific coast are in danger of earthquakes or tsunamis, and in some cases volcanoes. The coast is a nice place to live if one likes the ocean and beaches, but it comes with risk.

There is a particular feature near Fiji/Tonga that if it thruts up or down could cause a significant tsunami that would devastate many coastal cities from Australia, NZ and Chile, up to Japan, Russia, Alaska, Canada and the US.

Excellent! I'll be sure to lavishly wet myself every time I make landfall in those regions.

 

[rhody]

Apeiron, Astro, nismara,

You have to check this out: from: http://www.isgtw.org/visualization/visualizing-vectors" ...

This new seismic simulation tool is really, really cool, I will add a few key phrases:

• procedural dipole textured
• intuitive ground swell motion
• wave amplification
• display of flow like nature of seismic waves

There are other applications for this technology as well, Astrophysics...

Click the embedded video...

I think you will be impressed, I know I was.

Rhody...

 

[Astronuc]

I will have to navigate that later.

Meanwhile - http://www.isgtw.org/feature/feature-sixty-seconds-save-city

It seems that the Canterbury plains will be active for some time.