She missed pointing out the hundreds of nuclear bombs that were detonated in the sea water around bikini Atoll in the 50's and 60's which didn't kill the west coast.
But none of that really matters. It is an emotional fear not a rational fear that the exploiters play on. No amount of reasoning will get through that.
Specifically: nuclear testing released about 30 times more Cs-137 (in particular) than Fukushima, also mostly into the Pacific. An estimated 25 MCi  = 925 PBq, vs. 23-50 PBq .
(copied from an older HN comment I wrote)
edit: Here's a paper  which measured Sr-89 and Sr-90 in seawater near Japan: they found a ratio of about 0.026 of Sr-90 : Cs-137 -- relatively little strontium. Their estimate for total Sr-90 released is 90-900 TBq, corresponding to Cs-137 release estimates of 3.5 - 35 PBq. The figures for Chernobyl  are 10 PBq and 85 PBq respectively -- that is, Chernobyl released 10-100 times more Sr-90 than Fukushima. The Sr-90 : Cs-137 ratio was even higher (0.63) for atmospheric weapons tests: 600 PBq Sr-90, 900 PBq Cs-137 .
edit2: Made a table:
Sr-90 [PBq] Cs-137 [PBq] ratio ref
Fukushima 0.09 - 0.9 3.5 - 34 0.026 
Chernobyl 10 85 0.12 
Weapons 590 930 0.63 
 (large pdf) http://www.unscear.org/docs/reports/2008/11-80076_Report_200... (table 1, page 9)
Aside: until Fukushima is well and truly contained, the possibility of something catastrophic happening is still present.
Probability theory defers to physics.
I'll agree with the part that earthquakes aren't independent events...
EDIT: "The opposite occurred in Turkey along the great North Anatolian fault. A large quake in 1939 sent stresses farther down the fault, triggering a 60-year series of quakes whose latest installment was the deadly Izmit earthquake of 1999. The stresses have risen in the crust near the city of Istanbul, and a quake there is now considered more likely. " - http://geology.about.com/library/weekly/aa022303a.htm
That the reactors are not contained, is not a separate event. It is cleanup that has not yet occurred.
You wouldn't say, "Well, I fell off my bike at 25mph on pavement, landing precisely on both kneecaps, which was highly improbable" and then say "the probability that my knee is bleeding is therefore lessened", would you?
Good for cocktail parties.
She should have probably co-written this otherwise excellent article with a subject matter expert instead of guessing.
She corrects herself just fine, but nice job on reading the article.
Which I agree with, but I still feel better about the accuracy of this article over pretty much anything else I've read about seawater contamination due to the Fukushima disaster.
She (slightly) committed the sin of believing that just because she's an expert in Oceanography, that she could also carry water in another scientific field.
Being as she is a physical geographer and given that the majority of scare articles have related to the spread of radionuclides and the so-called imminent danger to the west coast of the US (and countless doomsday-style scenarios that have been appearing since the events at Fukushima et al), having someone whose research has focused more or less on precisely the subject at hand is certainly relieving as well as enlightening
I think that's the point of this entire article, though. The scaremongering is being perpetrated by people who generally have no background in either oceanography or nuclear physics . So in my mind, whether she's qualified to talk about the materials released is largely moot. The concern among conspiracists is how this material is going to spread (and purportedly kill us all), and she's more than qualified to explain how such theories are an expression of Chicken Littlisms.
 Granted, neither myself nor many of us here have such backgrounds, but I choose to lend greater credence to the arguments of someone who does have such a background.
"Pacific bluefin tuna transport Fukushima-derived radionuclides from Japan to California"
I'm no scientist, but I found particular interest in:
"Inferences about the safety of consuming radioactivity-contaminated seafood can be complicated due to complexities in translating food concentration in actual dose to humans, but it is important to put the anthropogenic radioactivity levels in the context of naturally occurring radioactivity. Total radiocesium concentrations of post-Fukushima PBFT were approximately thirty times less than concentrations of naturally occurring 40K in post-Fukushima PBFT and YFT and pre-Fukushima PBFT. Furthermore, before the Fukushima release the dose to human consumers of fish from 137Cs was estimated to be 0.5% of the -emitting 210Po (derived from the decay of 238U, naturally occurring, ubiquitous and relatively nonvarying in the oceans and its biota; not measured here) in those same fish. Thus even though 2011 PBFT showed a 10-fold increase in radiocesium concentrations, 134Cs and 137Cs would still likely provide low doses of radioactivity relative to naturally occurring radionuclides, particularly 210Po and 40K."
From my understanding: yes, radioactivity is being transported and yes, the levels are higher. However, the levels are not significant compared to naturally occurring radioactivity that ends up being consumed.
This was a nice read, I look forward to referencing it and some of these comments.
In Chernobyl, most of the radioactivity fell into the forests, mostly away from human food chain (there are still recommendations to not eat too much berries, mushrooms etc. in many areas). The Pacific is 100% in human food chain.
Nature does not care so much about radiation than we do. The wildlife in Chernobyl had fared better after the accident simply of not having humans present. Some like Stewart Brand went so far as arguing for placing nuclear waste in dry cask storage into nature preserves. Just to keep them pristine.
And to be clear: calling out specifically how the alarmists have misrepresented radiation hazards (I've seen the wave-height map circulated misleadingly numerous times) is absolutely the right call.
Say we have two samples of radioactive isotopes, both of equal mass and which produce the same particles when they decay. Sample A has a very short half-life (let's say minutes). Sample B has a very long half-life (let's say centuries). Sample A is much more dangerous right now but, in a few weeks it will be mostly gone. Sample B, having hardly decayed at all, will be the bigger threat then. In a single catastrophic release, as in the case of Fukushima, you'd probably prefer to have a lot of B sent out. It'll be around for a while, but it's not too deadly and will disperse, effectively raising the ocean's background radiation by an imperceptible amount. A huge release of A might do a lot of localized damage. If you have a slow, continuous leak, B might actually be worse though, since it could build up while A will not.
Cesium 137 and 134 have moderate half-lives of 30 and 2 years respectively. Iodine 131 has a shortish half-life of 8 days. It's been 666 days (Gee, I wonder why this is popping up today!) since the Fukushima incident, so the Iodine 131 had now decayed to 0.5^(666/8) or roughly 1e-25 of it's original strength. It's basically gone. The Cesium will be around for a while, but it's a lot less dangerous than the Iodine was.
Funny Aside: Cs-137 is very commonly used in undergraduate student laboratories. Samples of it are relatively safe to handle without safety equipment and it doesn't need to be replaced very often. I once TA'd a lab course where students were asked to do some experiments with CS-137 and, in their write-up's, calculate the effective dose they received. Most got the right answer, but a few messed up their units and wound up with ginormous doses that would have killed a zombified rhinoceros! Some of these students noticed this and reasoned they must have made a mistake, since we probably wouldn't try to kill our students. A couple did get very concerned though! Most just didn't notice, which was a tad depressing for me.
There's places of natural fission occurrence on Earth, doesn't that mean that they are potential sources of Cesium-137? I searched multiple sites and found no relation between the topic of natural fission sites and either CS-137 or Cesium-137.
Why should this be a product of man-made fission only?
As to natural reactors, those did exist and they did produce Cs-137, naturally. However, those reactors ran only billions of years ago, so the radioactive byproducts, such as Cs-137, have long since decayed.
Any article telling me "you don't have to worry about fukushima because chernobyl was worse" is suspicious to me. It's the same as saying you shouldn't be concerned about this war, world war 2 was worse.