Earthquakes Earthquakes and more Earthquakes

sizemik

For those who may be interested in things Geological . . .

Just an update on seismic activity here in Christchurch. What's below is the seismometer drum for the last 24 hrs . . . it's been a strangely quiet day however . . .

Total earthquake count since Sept 4th 2010 is now 6,614 felt. The last 'decent' Quake was a couple of days ago at 4.3 and shook for about 30 secs. About 10 damage reports.

Interestingly the whole country has experienced a slight upswing in seismic activity as can be seen from the distribution of the last 30 quakes (below) felt over the last week.

Having studied Earth Sciences, the big concern for me is the implications for the South Islands "Alpine Fault" graphically portrayed below

The line of the fault can be clearly seen in this satellite photograph . . .

some interesting photo's of the fault . . .

Facts derived from scientific studies reveal the following . . .

The mainly dextral strike-slip (sideways) movement of the fault is a constant 30 meters every 1000 years (quite rapid) and movement occurs on average about every 160 to 200 years.

Movement includes some thrust movement (upward) of about 3 to 5 meters at each rupture and represents the building mechanism for the Southern Alps

The last rupture occurred 300 years ago (prior to european settlement) and so the fault is about 100 - 140 years "overdue"

The recent Earthquakes east of the fault increase the likelyhood of movement.

As a University Geologist recently commented . . . "The data does not make good reading"

This fault is quite fascinating, in that it is one of the few examples in the world of two plate boundaries locked at the same level, and grinding directly against one another above sea level in a land based and observable form.

Magnitude of past Quakes normally fall beween 8 and 9 on the Richter. The current overdue nature could (but not neccessarily) point to a higher level of energy release . . . possibly as high as 9.5

Could be an exiting time ahead . . . I'm picking movement is imminent (within the next 5 years) and be in the mid 8's with widespread damage especially on the west coast.

As this will be land-based movement, Tsunami threat is negligible.

Rock on . . .

Broken Promises

Fascinating.

(but I don't think I could live there expecting an earthquake any time)

still thinking

It really is quite strange at the moment isn't it? I'm just waiting for other crap to happen now. Funny, I was just saying to my partner the other day that I wouldn't want to be living on the Sth Island west coast right now with that fault line and all the recent activity.

Have you got any plans to move?

jean-luc picard

How do people live with the threat of earthquakes in areas prone to them?

I cant imagine that they all want to become jdubs so as to be saved!

Does the jdub message regarding earthquakes and the time of the end

have the same or more impact with locals?

sizemik

Strange as it may seem . . . having lived through the last 8 months of regular shaking . . . my fear of earthquakes is now negligible

My whole family (care of my constant lecturing) is far more knowlegable than previously, and we have firm escape/survival plans covering every scenario we can imagine. Most Earthquakes are pretty noisy . . . and the sound becomes uniquely recognisable after a while. This is the only "warning" you get and while it only grants a few seconds, we have been almost out the door on some occaisions before the first seismic wave hits.

Knowlege is power? . . . without a doubt.

Having said that . . . one could still take you out anytime . . . but then so can a drunk driver.

jlp . . . JW's are strangely timid about the subject here as far as their doomsday preaching goes (the locals are more likely to simply get pissed off with their bullshit). I had a lone 'brother' venture up my driveway a couple of months ago . . . we had a thirty minute discussion on Earthquakes, Geology, Volcanism etc . . . and he didn't make a single reference to the bible or anything remotely religious . . . no lit offered . . . nothing. It was quite a pleasant chat actually . . . then he just left.

Curtains

I bumped into some jw friends who has just returned from new zealand. They only visited the north island and seemed quite worried about the earthquakes and said how anxious people in NZ are. They said that quite a few people had left the South Island. Is this true?

Black Sheep

said how anxious people in NZ are

I'm central NI and haven't heard any worried locals. This is NZ, the Shaky Isles. The telephone book has a section on what to do. Schools teach kids what to do. TV has ads on what to do.

On a clear day I can see the smoke from our local volcano. When it gets active and the wind blows our way I can smell it. When you fish near it, the sulphuric acid stings your eyes.

A super-volcano similar to Yellowstone dumped ash all over my property in the past and will do it again in the future.

Our capital city is on a huge fault that you see every time you watch the weather forecast on telly.

Our biggest city is built on numerious volcanos. Another one was found last week.

Most of us have insurance.

NZ wouldn't even be here if it wasn't for earthquakes. Any Kiwi kid who wasn't asleep during geography should know that.

sizemik

Latest report regarding Christchurch was around 40,000 . . . about 10% of the cities' population. Many have left because of their home being un-livable or job loss rather than fear or panic. I expect more will be forced to on account of the economic impact over the next 12 - 24 months.

I have quite a few elderly neighbours who I have spoken to who are remarkably philosophical and quite resilient in their attitude. But New Zealand has regular Earthquakes . . . a 6 or greater every year on average. Ha . . . we've had 3 more since I started this thread.

A large Earthquake is a most unpleasant, not to mention dangerous event when it occurs . . . but it's remarkable how most now take it in their stride. While it remains a talking point . . . I think the anxiety levels are only marginally raised . . . which is probably healthy. Although some (my son for eg) definitely suffer more impact than others. I have an anxiety disorder, but I'm still here (for now LOL).

ballistic

Earthquakes in one place after another! ;)

Curtains

it certainly sounds good to hear that those who have left do not have the added burden of JW induced anxieity about the end on top of trying to live with a difficult situation.

Latest report regarding Christchurch was around 40,000 . . . about 10% of the cities' population. Many have left because of their home being un-livable or job loss rather than fear or panic. I expect more will be forced to on account of the economic impact over the next 12 - 24 months.

this must be tough and must be what my jw friends were talking about - it was a shock for them.

I have an anxiety disorder, but I'm still here (for now LOL).

sizemik - glad to see you can laugh

those pics that go with the geological survey are awsome btw - humbling too

Earthquakes Earthquakes and more Earthquakes

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