On March 11, 2011, the northeastern coast of Japan was struck by an earthquake that measured 9.0 on the Richter scale. This was the fifth strongest earthquake ever to hit Japan. The quake caused a tsunami (tidal wave) that destroyed many coastal cities.

This combination of natural calamities caused extensive damage to a nuclear reactor facility near the city of Fukushima. As of 4 April, when I am starting this discussion, there were still a number of uncertainties about leaking radiation. In fact, the newsmedia coverage has been pretty over-the-top, not surprisingly, since fear sells newspapers and advertising revenue.

Several members of the trip asked my opinion about the dangers of our trip. I feel pretty confident we are not likely to encounter an earthquake of that magnitude. While earthquakes in Japan are a daily occurrence, they are usually so small that people mostly safely ignore them. And where we will be traveling any waters we will be in are highly protected (and a good part of our trip will be inland). But radiation is something I'm not really equipped to talk about either from experience or book learning.

I opened up this discussion with an email to a number of people who I thought might be able to either cast some light on the situation, or at least point me to someone knowledgable. Among those people was Jonathan Ormes. He and his wife Jan have been members of the church for some time now, and Jonathan is a former NASA astrophysicist who is retired but still does some consulting.

I found Jonathan's information and advice to be very reassuring, albeit a bit daunting. I have excerpted from his email to me and hope you find it useful and helpful. Feel free to continue the discussion any time by sending me an email with questions or opinions.

Steve, I wouldn't worry about the radiation where you are going. The radiation readings are available on the Internet and below are a few recent values from Tokyo:

To put this into perspective:

* 0.1 micro-Sieverts/hour is the "normal" or background radiation level
    in Tokyo
* 1 Sievert for 1 hour might kill about 50% of people exposed. This is
    called a deadly dose
* 1 micro-Sieverts is a million times less
* 0.3 micro-Sieverts is 3 million times less
* Even though the levels of radiation are sometime 2-3 times elevated
    above the natural background, it should be perfectly safe.
* Note that radiation levels are going down
             

It is not so nice at the plant itself: 0.4 Sieverts (400 milli Sieverts) per hour = conditions in the Fukushima Daiichi plant. 2 hours at this level will burn skin like a sunburn and produce nausea and radiation sickness.

Don't go visit Fukushima.

The allowed yearly safe dose is 0.01 Sieverts. If you spent a year in Tokyo and the radiation was at it highest measured level, the total dose would be 2.6 milli Sieverts = 1/4 of the allowed exposure. If you are there 2 weeks, it will be about 1% of the annual allowed dose. The dose is below that of a standard chest CT scan.

I found a site where you can check radiation levels in Tokyo every day if you care to.

Mary Dudzinski asked what the comparble exposure to radiation is every day here in Denver. There is an interesting paper from the NRC (United Stated Nuclear Regulatory Commission) that discusses the Biological Effects on Radiation. This paper contains this interesting paragraph:

"Although radiation may cause cancers at high doses and high dose rates, currently there are no data to establish unequivocally the occurrence of cancer following exposure to low doses and dose rates (below about 10,000 mrem (100 mSv)). Those people living in areas having high levels of background radiation (above 1,000 mrem (10 mSv) per year) such as Denver, Colorado, have shown no adverse biological effects."

The University of Idaho has an interesting site that pegs Denver as having 50 mrems of radiation exposure a year from background radiation, plus other sources detailed in the tables there.

The interested / concerned reader is encourage to go to Google or a similar site and select Advanced Search and enter: colorado denver radiation levels and follow the links.