More from Wheels:
death toll stands at 145 and will continue to rise. Ruffly 300 are missing, but not all that number maybe actually missing. Many just freaked out and got in cars and drove. Some have been known to have been rescued, but can not be found in the "system" yet.
Of the biuldings that remain standing, at least 30% are damaged so badly, they will have to be demolished.
A comment has been made about the buildings being up to US standards. That is quite correct, apart from many of the older Historic ones of course. However, even those had been Earthquake strengthened. After all, we sit on two major plates and we are one of the most active earthquake zones in the world. We get ruffly 30 shakes per month across the country. Most are in the Magnitude 3 to 4 and sometimes a good rumble may reach into 5 just to remind us all where we live. The real big ones tend to be in far more remote
areas of the country and/or Deep and so we do not see damage at ground level. Having said that, we have still had major quakes in the past that have caused much destruction. So far a major populated City has not been struck till now.
So where am I going with this? Well, we are fairly well prepared for big quakes. Many buildings have been strengthened and new ones have been built to the latest requirements. Yet so much has been turned to rubble by what is really not a huge earthquake measured at M6.3. The "CTV" building was not new, but still built to a standard that should have survived very easily. In fact, it even had rubber shock absorbing mounts on the foundations. It was five stories and it collapsed into the ground like it was made of sticks. All that remains standing is the lift
Another building, the tallest in CHCH is The Grand Chancellor, at 26 stories tall. It has moved 300mm (1ft) out of line on it's foundations and is expected to fall any time, which will take out a couple of blocks and is heavy enough to create a ground shock wave.
So why the level of destruction??? and why so much destruction when only 5 months earlier, we had an M7.1 with no where near as much damage.
Well a very scary figure has come out, that has made all the seismologists freak. They have measured a Ground acceleration of 2G's. That is huge. That means that every building has had to withstand a force of 2x the force of gravity in a sideways motion. How many skyscrapers could standing being tip onto their side and held only by there base, unsupported above the ground and then shaken. So the news and suggestions among the geologists at the moment is, maybe they have to redo the equations that buildings are designed to.
CHCH (Christchurch) is a small city. The largest for the South Island, but only 350,000 people. So infrastructure is still small compared to Wellington and Auckland
. Wellington (the capital) is smaller in population, but it is the financial capital of NZ and being a small footprint due to geological factors, it has many skyscrapers. Auckland
is home to 1.8 million people and has many tall buildings and motorways that stand above the ground and so on. If this quake happened in either of those two, the damage and possible death rate would be huge and hugely crippling to NZ.
Related, but slightly aside, NZ is subject to a very rare, but very real threat. Super Tsunami's. We have never had one in Human time of NZ, but we have much evidence of these waves, with some standing as high as possibly 600ft. Just a few years back, a survey
was taken of the seafloor just off our coastline. To everyone’s horror, huge undersea landslides were evident of having occurred. So just two weeks ago, a detailed study of what, where and how big these things are. Fortunately none of them are off the coast of CHCH. But the North Island has many and just one being triggered could or would wipe out huge area's of population.
But hey, now to put all that in perspective, we are but a blip on the scope
of geological time. Something could happen tomorrow, or may not happen for another 10,000 years from now.