Is the world ending?

Myagi prefacture, Japan following the devastating tsunami: Kyodo News/Associated Press

The recent spate of earthquakes in Haiti, New Zealand, Chile and, the huge Mw 8.8 9.0 (Mw is a scale used for large earthquakes, modified from the well known Richter scale) in Japan appear particularly unusual. This has led people to ask if we are having more large quakes than previously. But, it seems that this trend is not anything special, albeit tragic. Rycharde Manne discusses this in some depth using data collected over the past 30 years, and finds that there is no trend of increasing large earthquake frequency. Apparently, three large earthquakes (greater than Mw 6.0) per year across the globe is about normal when we consider long term averages. And, despite having a seemingly bad run recently, during the 60s it was worse, with two of the biggest recorded earthquakes in Chile (1960) and Alaska (1964) at Mw 9.5 and Mw 9.2 respectively.

There are a couple of reasons why I think that things seem worse than before. The world is more populated than before. Therefore, when large earthquakes, an their accompanying tsunamis hit, there are more people to injure and kill, and more infrastructure to damage and destroy. In addition, information is so easily and rapidly transmitted these days, the devastation can be seen immediately, rather than taking days, as it would have in the 60s . The video below is an example of modern information technology, showing the havoc caused by the Japanese tsunami. 

I also think that people forget quickly. When something new and "exciting" comes along we tend to forget things from the past. It seems to be human nature. It can be easily observed at the small scale in our own lives. Kids, and adults, get new toys and the old ones fall by the wayside. I know I've done it.

Most of what I have discussed comes from an article on The Panda's Thumb by Matt Young. Matt also discusses the problems around predicting earthquakes and how it basically cannot be done. Of course there are some that claim it can be. One such fellow is Ken Ring, or the "moon man". Ken Ring is known for his weather forecasting almanac based on lunar cycles. I don't know too much about it but apparently he can be broadly accurate. But I suspect that it comes less from the moon and more from studying trends. However, it seems Ken has decided that earthquakes can be predicted using the moon and tides. Ken recently appeared on the current affairs programme in NZ, Campbell Live. The average "interviewing" aside, John points out some obvious flaws in Ring's methods. For example, Ken Ring says that earthquakes are most likely to occur one week either side of new, or full moon. Now I would be the first to admit that my mathematics is poor but, seriously. One week either side of new or full moon makes four weeks. Four weeks makes a month. That is some ridiculously broad predicting. Not only that, but it is pseudosience that is misleading and actually quite dangerous. If you want to read more, Phil Plait has the details here.




 

Light without flight

Stephens Island wren (Traversia lyalli) drawn by John Gerrard Keulemans

 This week's birds comes once again from New Zealand's extinct passerine birds fauna. I have previously posted about the heaviest bird capable of flight, the kori bustard. Today I introduce you to the Stephens Island wren (Traversia lyalli), weighing around 20 grams and the lighest  bird that is known to have been flightless. It was also one of only three known flightless passerines, all of which were island birds. Were, because sadly they are all extinct.

Flightlessness in birds is common on islands and is an artefact of an evolutionary history devoid of typically mammalian predators. This is evident in New Zealand which has the greatest number of flightless bird species than any other landmass. Subsequently, it is flightlessness that contributes significantly to predation vulnerability and ultimately extinction, another common occurrence on islands in recent times. And it is exactly this which led to the demise of the Stephens Island wren.

Stephens Island, or takapourewa is located at the northernmost tip of the Marlborough Sounds on the South Island of New Zealand. Up until the 1890s it was free from human impact and pests, and had become the last remaining outpost for the Stephens Island wren.  This changed when it was decided that the island would make a perfect place for a lighthouse. The remoteness and untouched nature of the island is beautifully highlighted by Prof. Richard Holdaway who said that it would have been like stepping back in time. Unfortunately for the little wren species, that moment marked beggining of the end. On such a small island, only 1.84 sq km, there is not much place to hide if you are a bird that can't fly, and especially from a cat. The lighthouse keeper, Lyall (from who the wren gets it's species name) had just that, a cat! According to legend Tibbles the cat made short work of the little wren and has been credited with single pawdedly wiping out an entire species. This of course is not true since the bird was previously found on the mainland. There is an historical account of what did happen on the wiki page.

One last thought I will leave you with is this question; if Stephens Island is 3.4km away from the mainland and the Stephens Island wren was flightless, how did it get there?

Can we see the forest for the trees?

 This year is the "International year of Forests". Check out the UN page here and get amongst it.