Early Friday morning (June 10, 2011), at about 3:00 A.M. local time, one of our new Monitoring Stations in Hawaii broadcast a Radiation Alert over the network, reaching a sustained level of over 100 CPM (Counts per Minute) for a period of about 15 minutes, peaking as high as 141 CPM at one point. The readings then subsided to normal background levels of about 37 CPM for that station, but within less than 2 hours, trended quickly up again to over 100 CPM for another 5 minutes or so. The graph at right depicts this activity.

For context, this is the Kauai station, and within the Hawaiian archipelago, Kauai is the main island at the far northwest end of the chain, actually 300 miles from the Big Island of Hawaii, placing it closest to Japan about 3,500 miles away. And to boot, the Kauai station is located on the north shore of the island, in Princeville. You can see the station on the map – the yellow, numbered circle at top left.

The station is operating a traditional Geiger counter, affixed with an external probe built around the same ultra-sensitive, oversized pancake tube as in the Inspector line of instruments, so it is capable of detecting low levels of Alpha, Beta, and Gamma radiation. Data output is through the headphone jack of the survey meter. The Geiger counter is set up for outdoor monitoring, protected from the elements under the eaves of the structure, with the thin mica end window of the Geiger-Mueller tube oriented downward to prevent contamination from possible fallout.

So those are the facts of the case. The question now is, “Did the Kauai station detect radiation emanating from Fukushima?” To answer that, let’s review these points:

First of all, the detection was not just a momentary spike in radiation which could be explained by an instantaneous background surge, a software glitch, or a connection aberration, all circumstances that have triggered false alerts before.

The level of detection was three times higher than normal background radiation for that station, and sustained for periods as long as 15 minutes, which rules out random spikes in background.

The sustained levels of high readings, not once but twice, and separated by subsistence to normal levels, tend to rule out a malfunctioning instrument. Having said that, we have a knowledgeable person in Geiger counter design looking into the validity of the data output.

The station reports that “the Geiger counter’s integrity was not compromised in any way that we can tell. Safe, dry, under the eaves.” and knows of no local explanation for the high readings.

Speculation was of a radiation burst from solar flares, but the recent sunspot activity reported in the news was already over, according to one source. And in the 7 years that I have been continuously monitoring, I have never seen a sustained, elevated radiation level like this from any solar flare activity.

I asked the Kauai station if the elevated radiation detection correlated with any rainfall at that time? Well, Kauai being the “Garden Isle“, the predictable response was, “Hard to say, it rains all the time here”. And besides, he was sleeping at 3:00 in the morning. We know that rainfall can contain naturally occurring radioactive contaminants, as even my own tests have confirmed. But my detection was slight, and the Kauai readings were quite significant. And if his radiation hit was rainfall related, why was this the first time his station triggered an alert, given frequent rainfall during the last week he has been monitoring?

Unfortunately, our Monitoring Stations on Maui and the Big Island were not operating at the same time, so we lack confirmation of readings. However, the Big Island station is run by a sailor with extensive experience in meteorology, and a few days ago, he essentially predicted these events, i.e. what he believes to be weather patterns steering radiation fallout from Fukushima to Hawaii.

And with that, my tentative conclusion is that the Kauai station did in fact detect radiation from Fukushima – it looks like it, it smells like it, and it feels like it.