Earthquake predictions

Continuing on the 地震 (earthquake) theme - this is Japan after all; one of the most tectonically active countries in the world. Last week the Japanese Government issued a fairly comprehensive report predicting the likelihood of major earthquakes occurring in the next 30 years. Now, some of this is geological tea-leaf reading, but a fair chunk of it is based on science and statistics.

It doesn't make for very reassuring reading either. Basically if you live on the Pacific coast south of Tokyo you are rolling the dice. And for every day that ticks by, the odds get shorter. Depending on the projected size of the earthquake, the potential number of fatalities quickly climbs into the hundreds of thousands.

Mind you, it's not much better up here in Hokkaido. To the east and southeast of the island lie two major fault lines, respectively the Kuril trench and the Japan trench. Here's a helpful map.

On the map, the two trenches are named in yellow on the top left, with the actual trenches the purple and orange (russet?) patches on the Pacific ocean side of Hokkaido and Tohoku.

Okay, the next diagram is a little trickier to explain, but thankfully you have RTE's very own earthquake expert on hand to to do so.

Yes, I know, lots of numbers and some of that indecipherable kanji writing. But let me take you by the hand ...

'M' is Magnitude. So, yes, you've guessed it, M7~8 refers to a magnitude 7 to 8 earthquake. The roman numerals indicate the possibility of an earthquake occurring in the next thirty years. A 'I' represents a less than 3% chance, whereas a 'III' means there's more than a 26% chance of something big rumbling our way.

'X' is where scientists think Godzilla will most likely appear.

So looking at the above map you can see that all down the Pacific Ocean side of Hokkaido we have an unhealthy mix of IIs and IIIs. A lot of IIIs in fact. All representing odds of 4 to 1 (or less) of a magnitude 8 earthquake occurring before my eightieth birthday.

Finally, we come to this equally cheerful graphic showing the potential maximum height of a tsunami should said magnitude 8 earthquake happen. Muroran is estimated to receive a tsunami with a maximum wave height of 9.4 meters. That's higher than your house. Hiroo-cho (広尾町) where I used to live (and where my heart lives still), is expected to be hit by a tsunami 25.4 meters high.

Twenty five point four freaking meters! In Dublin you would want to be living on the upper floors of the Capital Dock to avoid getting wet.

Thankfully, where we live in Muroran is forty-two meters above sea-level so we aren't too concerned (though I keep a surf board handy just in case). However, the elementary school where Sanae works is basically across the road from the sea. So, I am now making her wear a life jacket to work everyday. In Japan you can never be too prepared.

Earthquakes and p-waves

 

Earthquakes, as you may have noticed, are not uncommon in Japan. We had a rather big one late on Wednesday night. This link to NHK News shows what happened as it happened - what look like explosions are in fact power outages from electricity sub-stations.

It woke me (though my Japanese wife and reared-in-Japan son slept right through it. Centuries of geological-genetic conditioning perhaps? Could be a research paper in it.)

Anyway, the foreigner was woken. Now interestingly, I woke about a minute or so before the house began to shake. And even in my liminal state (with Sanae's snoring the only disturbance), I knew there was a tremor coming.

Earthquakes are essentially waves of energy dissipated from the source of the quake. And there are three types of wave: surface waves, p-waves ('p' for 'primary' or 'pressure'), and s-waves ('s' for 'secondary' or 'sheer'). S-waves are the ones that cause the seismic tremors resulting in damage. P-waves are considerably less intense and arrive before the s-waves as they travel through the earth considerably faster. Earthquake warning sensors are designed to detect these p-waves and provide advance warning of the stronger s-waves that cause all the shaking, rattling and rolling.

Here is a diagram I uploaded from the internet expertly designed  to explain waves.

Many animals can sense these p-waves (it is often why you see birds suddenly take flight before an earthquake strikes), as can some humans.

I am one of those humans. Apparently I am possessed of 'keen senses' (whereas Cian is often possessed of no sense at all) that can 'feel' the vibrations made by a p-wave. Which, here in Japan, makes me akin to a minor deity. Or a demon. I am not too sure which.

Anyway, not for the first time, I awoke in the middle of night knowing that there was an earthquake imminent. And I have no idea, coming from a seismically inert country like Ireland, how I ever developed such a sense.

3 years done, 3 to go

Today was also the half point in Cian’s secondary school education. And this being Japan, yes, of course, the event was marked with an official ceremony to which the parents were invited (expected) to attend.
So we went.
In Japan, second-level schooling follows the American system in that it is split up into junior high school and high school with three years in each (for, maths fans, a total of 6 years). At the end of junior high school there is an emotionally intense, tear-laden graduation ceremony, and then the same again three years later at the end of high school (but with everything dialled way up to 11).
However, Cian’s school is unusual (by Japanese standards) in that it is a single secondary school where students go for six years. With the result that there is no graduation ceremony at the end of year 3.
But no ceremony at all would go against the very fundamentals of Japanese society, rend open the portals of rice-eating reason, and unleash unimaginable chaos on an unsuspecting world.
So, instead they have the 前期課程修了式 which Google translate renders as
“Closing ceremony for the first semester”,
where ‘semester’ in this instance is three years long.
And, so we went.
To the school gym where all the students were presented with a very officious looking certificate, the school principal made a speech (and closed it out with a cúpla focal as béarla), and all the while the god-awful school anthem played on repeat in the background.
As a cultural aside: pretty much every school in Japan has its own school song. Invariably these sound the same (think Enya with more piano), with the same anodyne aspirational lyrics that invariably reference ‘the future’, ‘sky’, ‘wings’ and ‘dreams’. Inexplicably there is never any reference to more adolescent concerns like ‘contraception’ or ‘the shocking price of provisional license car insurance’.
The ceremony also marked the end of compulsory schooling in Japan (at 15 years of age), so from next month we have to start paying school fees. And you can imagine how much I am looking forward to that.

 

Saint Patrick's Day in Hokkaido

 

So we flew the flag to mark the day that’s in it. Sanae’s initiative. I made a few squeaks of embarrassed protest but quickly assented. Cian had already gone to school when we hung up the tricolour and declared a little piece of Hokkaido as ‘Tír na Gael’.
Later on in the day, when I was home for lunch, a couple were walking by and wondered aloud when the Mexicans had moved to Muroran.
Personally, I blame the schools, particularly the primary school teachers …