Links, explainers and videos on nuclear reactors, nuclear explosions and developments at the Fukushima Daiichi Nuclear Power Station in Japan. Check out our other explainer and resource link on the earthquake in general - including how you can help the relief efforts.
»» Nuclear Science 101: Brian Lehrer Talks With MIT's Neil Todreas
Earthquakes and tsunamis are related:
The Japanese word "tsunami" literally means "harbor wave." Tsunamis can be caused by a seismic, but also by a non-seismic event, such as a landslide or meteorite impact. The displacement in the water caused by any of these things is what then creates the tsunami. James Waddell, a physical scientist with the West Coast and Alaska Tsunami Warning Center, part of the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service, says a tsunami is "the result of the water establishing a new equilibrium." There's one very important thing to remember about a tsunami, Waddell said, "It's not just one wave, it's more like a river, like a surge of water. Even if it's only a few inches deep, it can knock you off your feet."
According to NOAA (the National Oceanic and Atmospheric Administration), earthquakes are warnings for tsunamis. In the U.S., the most likely place this could occur is called the Cascadia Subduction Zone which is a long sloping fault stretching from mid-Vancouver Island to northern California. This is where the Juan de Fuca and the North America plates meet. Because of the size of the fault area, it could cause an earthquake as big as the one that happened in Japan last week.
The last known great earthquake in the region was more than 300 years ago. During this earthquake, the waves reached as high as 30 feet. The United States Geological Survey (USGS) has an interactive map that tracks when people feel earthquakes. There were several responses around the world over the past week — from Oklahoma to Guatemala to Japan.
Tsunamis Travel Far:
It didn't hit the U.S. with anywhere near the force it hit Japan, but the tsunami's waves crashed onto Hawaii's shores as it moved through the Pacific on Friday morning. Waves nearly seven feet high were reported in Maui. The West Coast and Alaska Tsunami Warning Center works with the Pacific Tsunami Warning Center to measure tsunamis internationally, but they're specifically responsible for those that may affect most of North America.
Both Tsunami Centers, as well as NOAA, measure tsunamis by reading DART buoys (Deep ocean Assessment and Reporting of Tsunamis) that float on the surface of the ocean in different parts of the world. Each DART buoys is paired with an acoustic package on the sea floor that senses a change in water height. The buoys then send a signal to NOAA's satellite.
If the Tsunami Warning Center suspects a tsunami will hit North America, they issue warnings and advisories to regional and local emergency authorities. A "warning" is any area with an expected hit of waves measuring one meter or more. An "advisory" would be for waves 0.3 meters to one meter in height, and a "watch" would be anything less than 0.3 meters. Watches and warnings were issued by the Pacific Tsunami Warning Center for Hawaii on Friday, as well as U.S. territories of Guam, the Commonwealth of the Northern Marianas Islands, portions of coastal areas in Alaska, California, Oregon and Washington.
What about relief aid?
Several humanitarian organizations, many of whom already had services on the ground in Japan before the earthquake, are lending a hand post-quake. The International Medical Corps is one of them and is coordinating with local medical teams to attend to the survivors. Margaret Aguirre, Director of Communications for the organization says Japan has a strong medical capacity. "We're trying to supplement that and identify where there are gaps and communities that aren't getting reached," she said. According to Aguirre, 145 of 172 hospitals in the affected area are still taking patients. Moving forward, the biggest health concerns are what may result from contaminated water, as well as exposure to the cold at night, she said. Currently, the most common injuries are crushed and broken bones. Even though Japan has deployed high numbers of medical teams, Aguirre says, "Any system would be stretched" in this kind of disaster.
The Salvation Army is soliciting donations and support through their Facebook page, though they are not accepting volunteers. Neither is the American Red Cross, though they too are working on the ground in Japan to The International Medical Corps is working with the U.N. and with American Red Cross to assist Japanese medical teams on the ground.
Yesterday, Doctors Without Borders tweeted they are in Japan providing medical support in Miyagi Prefecture at mobile clinics and evacuation centers where "medical needs are increasing." Miyagi is the area where the tsunami and the earthquake had the greatest impact.
What happened with the nuclear plants?
There are 55 working nuclear plants in Japan. The two plants that were affected by the earthquake and tsunami are the Fukushima Daiichi and the Fukushima Daini plants on the northeastern coast of the country. As of Monday, Japan's Nuclear and Industrial Safety Agency reported that the Daini plant, the plant farther from the earthquake epicenter, is in stable condition, though not in service. One of the units is being cooled and two more units are in "cold shutdown."
After an explosion in the Fukushima Daiichi plant on Friday, the Nuclear Energy Institute reported on Monday morning that the plant units were cooling and are in stable condition, but there are still reports that the cooling is not completely under control.
Each nuclear reactor at a plant has three safety measures, many of which were built precisely in case of a tsunami or any other natural disaster. The precautions are meant to keep the reactor at a certain temperature to avoid a meltdown and the exposure of radiation. All three of the safety measures failed last week and there are continued efforts to keep the reactor heating rods cool by using sea water.
Professor Akira Omoto of the Japan Atomic Energy Commission was involved in the construction of the Fukushima plants. "We thought we had taken adequate precautions for a tsunami," he said, speaking to Reuters, "but what happened was beyond our expectations."
World Nuclear News is providing regular updates to the status of the vulnerable nuclear plants. The New York Times has an interactive diagram of how the nuclear reactors are supposed to work, and what went wrong.
Map of nuclear reactors and fault lines in the United States, via The Takeaway.