Magnitude 7.3 earthquake off the Coast of Fukushima Prefecture

The thing most people don't mention is that after the March 11th 2011 earthquake, we had daily aftershocks, the kind you could easily feel, which lasted for months. Seems to happen mostly at night, most disconcertingly, as I was woken up out of bed more times than I could count with ones large enough to cause me to jump up and think the "big one" was hitting Tokyo.

Took me a good year, and moving out of Japan, to calm down about it and realize just how much daily stress it had caused me, how much on edge you are after something like this. Of course, nothing happened, but when your system is constantly in heightened awareness mode, the way I expect soldiers in a warzone feel wondering if there's someone around the corner waiting to get you, you start to build up PTSD in a real way.

Side note: add in a bit of nuclear fallout concern, plus having young kids and some playgrounds in Tokyo getting abnormally high enough readings they had to close them... oh, in addition to tainted food supply, and you'll maybe understand.

yamazakiwi• 4 years ago

I remember the aftershocks, and I still have ptsd regarding earthquakes. I've felt a few small ones back stateside and feels like it starts the cycle over again. Not sure how long it will take for me to get over it.

Hulitio• 4 years ago

We visited Japan 3 years ago and it stuck with me how normal earthquakes, alerts for this and tsunamis are.

Like wtf!

lostlogin• 4 years ago

The Christchurch earthquake in New Zealand had a lot of aftershocks and a lot of people left the city to avoid them. Here is an article saying that there were 11,200 aftershocks in the following 2 years.

https://www.odt.co.nz/news/national/11000-aftershocks-christ...

8ytecoder• 4 years ago

Living in the Bay Area and right atop a fault, I feel phantom shakes. I usually have my ham radio tuned to the local repeater and people start reporting real ones almost instantaneously. So I use that as indicator to calm myself.

Hasn’t affected my life but it’s always there in the back of my mind. I realised I’m also a lot more sensitive to them than anyone else I know. Almost all the major ones - including the one in Napa have woken me up, usually in cold sweat and heart palpitations.

danuker2• 4 years ago

Hope today's was not the foreshock to something bigger.

Denvercoder9• 4 years ago

For those unware, the magnitude scales used to measure earthquakes are logarithmic, with released energy increasing by a factor of about 32 (10^3/2 to be exact) for each step. Thus, the 9.1 earthquake from 2011 released about 500 times as much energy as the one from today.

thrdbndndn• 4 years ago

I feel like it should also be added that part of (not all) the reason we use logarithmic scale for these things to begin with is precisely because their "damage" or impact is not linearly correlated to the energy released from the event (same goes to dBPL used in sound pressure).

Unfortunately, it's not linear to the logarithmic scale either so it's hard to get a intuitive "feeding" from it.

I'd say it's something in between but closer to the linear scale in earthquake's case.

andrepd• 4 years ago

Reminder that 9 isn't ~25% larger than 7, its 100x larger.

x62Bh7948f• 4 years ago

I felt a 3-ish small one for about 5 seconds and then it was over. About a minute later it began again but this time it was definitely over 4 (I’m in Tokyo). It was long too, almost a minute I think (by the end it was not so strong, maybe 4-5 during the first 15 seconds or so)

mlindner• 4 years ago

Just to clarify for others, the numbers used in the above post are shindo-scale which are a location-dependent measurement of actual movement. They are used much more in Japan versus magnitude numbers.

genewitch• 4 years ago

i used to live very close to a fault in Los Angeles County, and the numbers i remember from the 80s and 90s don't seem to correlate to the numbers i hear now - i left CA in 2006. The running joke with my CA friends is "don't even tweet/post about it unless it's a 7.0" whereas a 7.0 would mean widescale destruction back when i lived there. I remember the Apple Valley Quake, it was a rolling quake, and it was somewhere between a 4.8 and a 5.4. It derailed trains, and caused a bunch of property damage. I had a ham radio at the time and i was tuned into two of the biggest repeaters in southern california (one being "the nut") and listened to the damage reports and movement of emergency crews.

We were quite far from that one, and it wasn't violent, but it still caused property damage and power outages due to shorted lines.

So i see a 7.3 magnitude, and since i no longer deal with earthquakes (just floods, hurricanes, and tornadoes), i have no frame of reference for how bad that is. Gauging off the running joke above, it's gotta be somewhat bad, right?

Kuinox• 4 years ago

Tsunami advisory: https://www.data.jma.go.jp/multi/tsunami/index.html?lang=en

coobird2• 4 years ago

It was two earthquakes -- one "small" one and another "big" one that followed about a minute later.

On TV, they were announcing the quake intensity of the first one and and there was a video feed of the Fukushima nuclear plant, as they usually do when there's a strong quake in that area. A moment later, the feed was shaking violently -- I thought it was a replay of what was taken earlier, but it must have been the "big" one.

In Tokyo, we felt the secondary wave of the first overlapping with the primary of the second, so it was disorienting and scary. Although the quake intensity itself wasn't serious in Tokyo.

coobird2• 4 years ago

Well, seems like a Shinkansen derailed. It doesn't seem very serious as there's someone tweeting about it from inside that train...[1] There's also a tweet that the part of the overhead power line broke off and fell[2], so it may take a while to get back in service...

[1] https://twitter.com/tokimemo1130/status/1504110997732139024

[2] https://twitter.com/R19i90/status/1504112207746936832

ehnto• 4 years ago

I would be interested to know more about the derailing. The shinkansen network has automated quake protections that stop the trains when a quake is detected, while that's not a foolproof system, I am sure a derailment at full speed would be very different to this picture. Either it worked or the train was at a slower part of it's journey, perhaps even stopped.

GolDDranks• 4 years ago

The big wasn't still very big here in Tokyo, but it felt weird. The shake was in different direction than usually, it's hard to describe. It also lasted quite long in detectable intensities, although the peak shake was over pretty quickly.

numpad0• 4 years ago

That’s the transverse Secondary wave from a distant origin. It feels like you’re suddenly put on a ship rather than like the ground exploded. I learned that anecdotally…

graderjs6• 4 years ago

Largest quake in at least a year in Japan. Also strangely almost exactly 12 months since a 7.0 in the very same area (20 March 2021): https://earthquake.usgs.gov/earthquakes/eventpage/us7000dl6y...

kijin• 4 years ago

The infamous 2011 earthquake was also in March. Is there any plausible reason for earthquakes to occur in the same region around the same time of year over and over again, or is it just coincidence? I don't think Japan has any large glaciers that could melt in the spring and shift the center of mass of the plate underneath, for example.

toyg• 4 years ago

Maybe something to do with orbital forces / sea currents...?

graderjs6• 4 years ago

Great question. 1/12 x 1/12 x 1/12 -- odds seem kind of low...but could possibly be related to ocean currents, seasonal flow systems probably significantly shift the center of mass of large bodies of water, maybe related to temperature.

danuker2• 4 years ago

Maybe thermal expansion, since March means warming after winter.

pvaldes3• 4 years ago

My guess would be that ice melting in the caps triggers a release tension cascade in several parts of the crust, but is just a feeling. Less weight in the poles could make the planet tend to go more "sphaerical".

Just my own stupid theory. I'm not a geologist and could be wrong by a mile.

bithavoc• 4 years ago

Do we have to worry about the nuclear plant? Is it still active?

mark-r• 4 years ago

No, I don't think that plant will ever be active again. There might be a danger if a tsunami came through again and washed more radioactive debris out from where it settled.

npteljes• 4 years ago

It's not active.

https://en.wikipedia.org/wiki/Fukushima_Daini_Nuclear_Power_...

amelius• 4 years ago

We do have to worry about the nuclear agency that allowed it to be built there in the first place ...

prpl• 4 years ago

less than 1 week difference 11 years later.

darkteflon• 4 years ago

That was big. First time since the 2011 quake that I actually put the emergency backpack on. Another 10 seconds and I reckon we would have woken our son and headed outside.

88840-88552• 4 years ago

what is the emergency backpack?

alephnan• 4 years ago

https://www.nhk.or.jp/sonae/en/goods/index.html

ihumanable• 4 years ago

They also sell these in the US as well.

Products like this

https://www.homedepot.com/p/Ready-America-2-Person-3-Day-Eme...

They are good to have if you live in an area with natural disasters, 5-year shelf life and you just keep it somewhere that you can quickly grab if you ever need to evacuate.

MrYellowP• 4 years ago

Right on schedule.

Shadonototra• 4 years ago

Chip plants and nuclear plants in high seismic activity land

People who gave the greenlight should be in jail for the rest of their lives

fomine3• 4 years ago

All nuclear plants survived for many earthquakes, but F1 failed for a tsunami.

Magnitude 7.3 earthquake off the Coast of Fukushima Prefecture

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