I recently found an article that says the subduction zone off the North Island East Coast has been ranked as being at high risk of generating a giant earthquake. New research rated a 600-kilometre section of the Hikurangi-southern Kermadec subduction segment, starting at the lower North Island and stretching to the northeast, as having the highest risk of producing a giant quake of a greater magnitude than 8.5.How nice, how charming, and of course, you can guess where I live. Yup, that’s right, within that zone. It isn’t enough that we’ve had a whole string of quakes in the past three years, now we should watch for really really massive quakes and tidal waves?
It goes on to say that “ateam led by Associate Professor Wouter Schellart, of Monash University in Melbourne, developed a global map in which individual subduction zone segments were ranked in terms of their predicted capability to generate such a giant. The largest earthquakes happen only at subduction zones. Each zone segment was ranked according to six parameters. In the highest risk segments all six parameters fell within the ranges seen in previous quakes of greater magnitudes than 8.5. According to the research, the Hikurangi-southern Kermadec subduction zone segment had the characteristics of the locations of previous giant earthquakes, Schellart said. “It should be capable of generating a giant earthquake as well.”
Oh right, that’s just what I wanted to hear. Although it could be worse, at the some 1400 ftabove sea-level that I am, it’s unlikely any tidal wave will reach farside, and if it does I’ll have the thin consolation of knowing that almost all of the country has preceded me into oblivian. Then again if the quake was 8.5 or thereabouts I’ll probably have died before any wave gets here, which again is rather thin consolation.
Schellart said “The crust in the southern part of the North Island is being shortened and compressed, which implies that the subduction zone fault has high stress on it, which can mean that the fault is temporarily locked. If that part slipped it could create a large earthquake and potentially could result in a cascading effect, causing segments further to the north to slip as well.â€
Great, so we are informed that not only could there be a ‘great quake’ but that it may even be likely. In the Boxing Day quake of 2004, 400-500Km slipped in similar circumstances and that’s what this subduction could do too. The expert thinks that the biggest worry would be that a giant quake could also cause a tsunami. Hmmm. If I’m dead under the ruins of my 8.5-quake-struck house, I doubt I’ll care. But the final two items made me twitch slightly. The expert said that “he was not an expert in tsunami modelling but thought the tsunami could be “metres” high.and “he could not comment on when such an earthquake might happen. My conclusions are that I probably don’t have to worry about the tsunami – unless he really meant “hundreds of metres. (and it would have to be over 400m high to reach here.) I can ignore the giant quake as well. If an 8.5 hits my immediate area there’ll be nothing I can do, not even my 130-year old solidly-built farmhouse will stand up to that. The big shelterbelt trees all aound the house will fall, and it occured to me that as I can’t move fast, I’m bound to be under something when it lands. I’ve therefore decided to forget it. There’s nothing I can do, and right now I’m in the middle of writing a book, x weeks short of birthday celebrations (my 68th) and anticipating friends arriving in a couple of hours to have lunch with me. I don’t have time to worry about earthquakes, scientists, or tidal waves. I have to go out and push a hen off her nest so I have eggs to scramble…