Fukushima Nuclear Plant

This is a link to an article in the New York Times. If there is a simple lesson, it is that society ignores advances in science at its own peril.

WORLD | March 27, 2011
Japanese Rules for Nuclear Plants Relied on Old Science
By NORIMITSU ONISHI and JAMES GLANZ
For decades, Japanese officialdom and even parts of its engineering establishment clung to older scientific precepts for protecting nuclear plants.

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Here is a link to a similar article in the Japan times:

Signs of disaster were there to see | The Japan Times Online
http://search.japantimes.co.jp/cgi-bin/nn20110327a3.html

Earthquakes in Japan and around the world. (III)

The map below shows foreshocks and aftershocks of the March 11 Tohoku earthquake. The list of earthquakes and locations comes from the US Geological Survey web pages:

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_big.php

Only events with magnitude 5.0 or larger are listed on that page.

There is a similar, and up-to-date map on the USGS web site:

http://earthquake.usgs.gov/earthquakes/seqs/events/usc0001xgp/

(accessed March 26, 2011).

The figure below shows magnitudes as a function of time, based on the same USGS web site.

A model for the numbers of aftershocks as a function of time after an earthquake is called "Omori's Law." According to this, the rates of aftershocks decrease as a function of time, following the equation n(t)~(c+t)^(-p). The plot below tries fitting the integral of this equation to the cumulative numbers of aftershocks, based on the USGS list. This curve does not fit the first two days of the aftershock sequence. Also, the value of p seems to increase as time goes on for this catalog.

A large aftershock could happen, and significantly alter the course of this curve.

Earthquakes in Japan and around the world (II)

Following on my last post, this figure shows the cumulative numbers of earthquakes with magnitude of 5.0 or greater that are not in the Japan region. It would be better to have a longer sample from before the 2011 Tohoku earthquake, but based on what I do show, and not using any sophisticated statistical tests, there is not an obvious change in rate at the time of the 2011 Tohoku earthquake.

Earthquakes in Japan and around the world (I)

Since March 11, I've been watching the global seismicity. Here is a map of the events with magnitude 5.0 or larger as captured from the USGS web pages:

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_big.php

Plate margins are shown in green, and events in the vicinity of Tohoku are shown in red. Starting about 5 days before the 2011 Tohoku earthquake, there are over 450 events on this plot.

The plot below shows the cumulative numbers of earthquakes and the cumulative number in the Japan region. Aftershocks of the Tohoku earthquake are dominating the cumulative plot, but they are slowing down in numbers.

Securing Kitchen Cabinets for Earthquakes

We use brass cabin hooks to prevent the doors on our kitchen cabinets from swinging open during earthquakes. They are relatively easy to use, and to our aesthetic tastes, they look good. After an earthquake, be very careful opening cabinets. Objects inside will likely have moved around, and can fall out when the doors are opened. The first photo shows adjacent doors hooked together. In the second case, it is a shorter hook for a single cabinet door.

Securing Small Decorative Objects

We secure small, decorative items with QuakeWax. A similar product is also sold as "Museum Wax". For instance, the items on our mantle below are all secured with a small amount of QuakeWax on the bottom. From the photo is is clear that you cannot see that there is a layer of wax under the vases. This system worked well for us in the Mogul earthquake in 2008. Only one item fell; that was to be honest too large and heavy for the wax to have any chance of holding under accelerations of about 1g.

Securing Books in Shelves During Earthquakes

Once the shelves are secured to the wall, we also wanted to prevent books from falling out. This is a thin wire running in front of some books. In the Mogul earthquake, this method worked.

Securing Bookshelves to the Wall for Earthquakes

This photo shows how we secured some of our bookshelves to the wall for earthquakes. When I visited Hiroshi Kawase at Kyoto University, he showed me a demonstration of a ~6 foot bookshelf toppling in a simulated earthquake on a shake table. It was actually VERY impressive. When the shelf fell, it landed with extreme force. I don't see how anyone receiving the brunt of that fall could escape without very serious injury. So securing bookshelves is important.

What you see here is a 3 inch angle iron. The top of the angle iron is attached to the solid wooden top of the bookshelf, but on the inside. The back side has long screws going through the thin plywood backing and plaster, into a wooden stud in the wall in back.

We had this system in place during the strong shaking we experienced during the Mogul earthquake. All of our shelves remained secure. This one is on the second floor of our house. The Mogul earthquake had a peak vector ground acceleration, recorded in our yard, of 1.19g, but the duration was short because it was only a magnitude Mw=5.0 event. So the lack of long-period energy means that this was not the most severe possible test. Still, the shelf also feels very secure when I try yanking on it, so I think this system is sufficient.

Securing Computer Equipment for Earthquakes

We use a very simple system to secure our computer equipment. An example is shown in this figure.

The blue and white strip is the back side of a strip of velcro. The other side of the velcro has an adhesive backing. We attached one short strip to the table, and another to the printer. The strip on top holds the two together. We had this in place during the strong shaking in our home in the Mogul earthquake, and it was completely successful in preventing computer equipment from sliding around.

Securing Pictures for Earthquakes

This is one of our favorite pictures, called "The Great Wave off Kanagawa" by Hokusai. We bought the print in Japan. We certainly do not want it to be damaged by an earthquake.

The picture is mounted with a wire in back, as shown above. It is important that the wire is not too tight, because if it is, under strong shaking it can break where it is wrapped around the eyelets at the ends.

The hook is called “The A-Maze-ing Picture Hook” by TREVCO, Escondido, CA, USA 92029, www.quakehold.com. The idea is that by creating a maze for the wire to go through, it will not come out during an earthquake. We were using a different kind when we went through the strong shaking of the Mogul earthquakes, but these are easier to use so we have switched to them.

Thanks to my wife for taking these pictures.

Earthquake Preparedness

My wife asked me to summarize how to prepare for a possible earthquake. Here is what I suggest:

1. Protect yourself from physical or financial harm.

Look around, see what could be harmed, and do what you can to prevent that harm. Some essentials: attach furniture, televisions, or anything else that might fall, so nothing will topple on you, your family, or your pets. Also figure out a way so that valuables, like computers or precious objects will not fall and break. Also, attach your water heater, and anything that uses a gas line, because you don't want the gas line to break and cause a fire. You also want to attach the water heater because you don't want the water line to break and cause a flood.

2. Be prepared for the recovery period.

For the worst case, be prepared to "camp out" in your home for 3-5 days without any services - electricity, water, gas, etc. So keep several days of food that does not require refrigeration, water, and medicines (if any), in the home and also in the office. We like nuts and chocolates, and canned beans for nutrition. Also, have enough warm clothes or blankets in case you lose heating. Think about the tools and other things that you might need - wrenches to turn off gas in case of a leak, flashlight, radio or cell phone (with a charged battery). Make a plan for getting in contact with your family and friends. Also it may be good to have a cash supply in case the banks are closed for a few days.

3. After you are prepared, be prepared to help others.

There are lots of good lists with more details, but with these principles and your own imagination, you can prepare well.

Why the Japan M9.1 Earthquake Matters to the USA

Yesterday's M9.1 Japan earthquake will affect the USA in many ways, because of our close economic and cultural ties. These thoughts are confined to the scientific relevance.

The Japan earthquake has a magnitude similar to the magnitude of the 1700 Cascadia subduction zone earthquake. The following screen captures from Google Earth are on the same scale, and indicate that the rupture length in Japan is apparently a little smaller than the full length of the Cascadia subduction zone. But the scales are similar. The ground motions recorded in Japan are thus very relevant to predicting ground motions to result from the next Cascadia earthquake. The ground motions from this earthquake are very well recorded by the excellent Japanese network. They will become the reference for potential ground motions from future Cascadia earthquakes.

First posted March 12, 2011. Updated March 29, 2011.

Japan Earthquake, March 2011, MW=9.1

I heard about this earthquake last night about 10:30 PM. Initially the magnitude estimate was lower, but the USGS moment (2.8e29) gives MW=8.9. The Global CMT Project moment (6.03e29) gives MW=9.1.

The following is a screen capture from Google Earth, showing aftershock locations. Yellow colors are foreshocks. The aftershock zone is about 180-200 km wide, 400-450 km long. A zone that is 200 x 400 km, with the USGS moment, implies mean slip of 9 m. That would be 100 years of slip accumulation based on the convergence rate shown on this map.