The Great Northern Osaka Earthquake 6/18

Update: Last night (Saturday June 23) at 11:08 PM we experienced a 4.0 magnitude aftershock. I had just finished putting the mattresses from our bedroom back into the kids’ rooms. Alas, Nadia insisted on the kids sleeping in our room another night. 

Our family experienced our first serious earthquake on Monday since we moved to Japan almost four years ago. It was one of the most awesome experiences I’ve had. Awesome meaning the formal definition of the word, awe-inspiring, with awe being “a feeling of reverential respect mixed with fear or wonder”. Without warning, having the room shake violently for 10 seconds is awesome. I’ve been through many minor shakes and rattles, but never one where it made the room look blurry due to the intense shaking. I never thought the ceiling would collapse on me or I was in danger of dying. My mind was in awe and all of us in the school community were shaken, both physically for the 10 seconds of the earthquake, but more importantly, emotionally and psychologically.

I listened to a recent Malcolm Gladwell’s Revisionist History podcast about memory and he refers to the concept of a “flashbulb memory” This is a person remembers exactly where they were when they heard the news of a big or historical event, like the attack on the World Trade Center on 9/11. This earthquake for the Kralovec family will be a flashbulb memory. In the episode linked above, Gladwell argues that our flashbulb memories fade and change over time and details become mixed with other events and times. I asked our family members to write down their memories for posterity. To my descendants and others who may be reading this in the future, you should do this for the big events that take place in your life.

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Art displays knocked down at school.

The earthquake hit at 7:58 AM on Monday, June 18. The epicenter was only 10 kilometers from our school in the neighboring suburb of Takatski. It measured a 6.1 on the moment magnitude scale and 6-minus on the Japanese intensity scale and we felt the full strength of the quake in our suburb of Minoh.  I was in our daily administrative morning meeting when suddenly the room started moving. The first big jolt was an up-and-down motion, not the side-to-side that I’ve experienced before. We quickly went under the table. One of the other administrators let out an audible cry. Because we were so close to the epicenter, the “advanced” warning call of “jishin!” (earthquake in Japanese) sounded on our phones while we were under the table.

Once it stopped, we left the conference room to assess the damage. There were books and papers all over the floor in the business office. After seeing that everyone was OK, I went on the PA system and asked for everyone to evacuate the building and go to the soccer field as we practice in our crisis response drills. This was different from our protocol because we usually ask people to stay put while we assess the damage and check for fire. However, with so few people in the building and so many people soon to be arriving, I didn’t want a stream of people coming into the school and felt that the soccer field was the safest place to be.

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Nadia had the kids sleep with us in fear of aftershocks

It was an odd time for the school because students and parents are just arriving for our 8:30 AM start. For those students who live close to the school, they may have been at home and many were in transit. 75% of our school lives in one of the three neighbouring suburbs, although 25% have longer commutes and use public transport.

As the head of school, I first thought of my responsibilities to our students, faculty and staff. However, I am a father and husband and I was worried about them. When I got onto the field, I saw Oliver’s blonde head and soon thereafter arrived a hysterical Nadia clutching Ocean, so I was relieved they OK.  My eldest son Owen was in Malaysia at the World Scholar’s Cup. He called later in the morning to make sure we were safe.

We eventually got everyone home safely, including loading up a school bus and driving down to Kobe with the students that lived over there. All of the trains and buses were stopped. Luckily, the electricity and internet was not cut and you could text and call people with your mobile phone. Without that, I am not sure what we would have done! We cancelled classes on Monday and Tuesday and the faculty and staff spent two days cleaning and tidying the school. The quake was powerful enough to knock paintings off the wall, dislodge books and equipment from shelves, etc. Not only at school, but at homes as well.

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A sheet of stucco fell on our wall at our home

At our home, one painting cracked, one light fixture came down and some drywall/wall paper cracked. On our patio, we noticed some of the stucco foundation of the house crumbled and a big sheet of concrete sheeting fell off our wall around our property. It also split the brick bench on the patio.

Nadia was in the bathroom of our house with Ocean brushing their hair in anticipation of leaving for school. Oliver was on his bicycle waiting at a stoplight a few blocks from our house. I’ll record them talking about the earthquake and upload it as a podcast for posterity.

Thankfully, no one was seriously injured in our community. The quake killed five people and injured 420 people. Sadly, a nine-year-old schoolgirl was crushed to death by a 2-meter wall collapsing near her school. There were many aftershocks, ranging from 4.0 to 2.1 the two days following the initial earthquake. As I am revising this on Saturday June 23, there has not be any recently.

The earthquake put people on edge, waiting for a similarly sized tremor. Some families left the city and checked into hotels in case of another big quake. I think finally, people are settling down and getting back into their routines.

Japan probably knows more about earthquakes than any nation. I read several good articles quoting geologists and university professors. I am learning a lot about earthquakes!

active fault zones around the epicenter

Scientists believe the earthquake was caused by three possible faults (see diagram). The Uemachi fault runs directly through downtown Osaka is the most likely of the three to have an earthquake of magnitude 7.5 or greater in the next 30 years, with geologists giving it a 2-3% chance. My town of Minoh is 10 kilometers directly west of the epicenter, probably on the Arima-Takatsuki fault line. This earthquake was the biggest ever to strike Osaka.

The Great Awaji Earthquake of 1995 was the last big earthquake to hit here in the Kansai region of Japan. That one struck at 5:46 AM on January 17, 1995 and had a magnitude of 6.9. Over 6,000 people died and there was a lot of damage in Kobe.  

Japan also has the most extensive network of earthquake detection equipment in the world with 180 seismographs and 627 seismic intensity meters. They even have their own measurement scale for earthquakes, which is older than the Richter scale. It measures earthquakes in units of shindo (震度, seismic intensity, “degree of shaking”) In the west, the Richter Scale (1930) and its replacement (1970s) the Moment Magnitude Scale (MMS) measure the amount of energy released.  The Japan Meteorological Agency (JMA) scale goes from 0-7. Strong earthquakes, the ones where people are frightened and notice a lot of shaking start at 3.5. We experienced a 6.1 (MMS) and 6 minus (JMA) earthquake this week.

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The Nankai Trough off the coast of Japan – the west section across from the Nagoya airport has not had an earthquake in over 160 years. The other two sections, near Wakayama and Shikoku have had quakes more recently.

Disconcertingly, the JMA predicts there is a 70-80% chance that a powerful quake with a magnitude of 8 or 9 will occur in Japan within the next 30 years. Mega-quakes have repeatedly occurred in the Nankai Trough (see diagram) off Japan’s Pacific coast at intervals of 100-200 years.  It says the quake will inflict serious damage mainly on the Shikoku (smallest of the four main islands of Japan, just south of Osaka), Kinki (our region) and Tokai (north of us, basically the city of Nagoya and adjacent prefectures).

I read an article by Robert Geller, professor emeritus at Tokyo University that says seismologists cannot accurately predict earthquakes and the public should disregard the JMA predictions, and I kind of feel he is right. Science does not yet have the understanding and insight of plate tectonics to be able to accurately predict earthquakes. I am surprised that the Osaka Earthquake already has a wikipedia page.

Best reference:

https://www3.nhk.or.jp/nhkworld/nhknewsline/backstories/threefaultzones/

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