Time Lapse of PA Harbor during Tsunami

Using CHDK on my bottom of the line Canon PowerShot I shot about 60 photos on a time lapse setting (one every 30 seconds) of Port Angeles Harbor between about 2:30 and 3:00 PM local time. I got lucky - the periods of the tsunami waves propagating through the Strait of Juan de Fuca are about 30 minutes - so I captured a full wave before my POS camera failed. The currents generated within the harbor associated with these waves are fairly minimal, though there is a noticeable current at the entrance - maybe 2-3 knots. NOAA CO-OPS data suggests a wave amplitude at this time of about 50-60 cm. You sort of have to look close - focus first on the dock piling in the near field.

Tsunami on the North Olympic Peninsula

My son is 13 months old. Just after he was born the Chilean tsunami generated a wave that was visible on the shores of Santa Cruz, where we lived at the time. I dragged the family down to a building above the beach and we watched as the waves hit. It was visible, but damage was minimal, and it provided more of an ooh-ahh moment. I posted to this blog the day of that event.

Today's tsunami was much more significant for the west coast. Santa Cruz harbor has experienced damage in its harbor. Initial reports from Crescent City suggest significant damage. Here in Port Angeles I am getting reports of well over a meter (54 inches) of water level fluctuation, though thankfully without enough current to do any damage yet.

For those of us on this side of the Pacific this event will do some damage, but, on the scale of what we may experience in the future, this is a small event. Our thoughts must be first for those killed or missing in Japan, Russian and other parts of Asia most impacted by this earthquake and tsunami. Some of the video coming from Japan and Russia is astounding. Unlike most of the video that emerged from the Indonesian tsunami, much of what we are seeing is hi-def and taken from the air. It provides some insight regarding what we could experience from a Cascadia Subduction zone earthquake generated off of the shores of Oregon and Washington.

NOAA has generated a propagation model for this tsunami, the results of which suggest that Chile will see some of the most damaging wave heights from this event on this side of the Pacific:


The scale that they provide here, I assume (I haven't yet looked into the details of this model) tries to predict the wave height in deeper water. Tsunami waves are hugely long, many kilometers, but in the open ocean their heights can be just tens of centimeters. However, as they approach the continental shelf interactions between the energy propagated in the wave and the bottom causes the wave to slow and the wavelength to shorten. The wave responds by growing in height. My point in providing this brief explanation is to suggest that the scale on this model output shouldn't be taken as suggestive of the wave height at the shoreline.

What comes next are a series of plots taken from the NOAA tides and currents web site, generated by NOAA Center for Operational Oceanographic Products and Services. Each plot has three tracers: In blue is the predicted tidal water level, in red is the observed water level, and in green is the difference between the two. The green one is the one to pay attention to.

On this side of the Pacific it appears as of right now that Crescent City, CA is seeing the largest waves associated with the tsunami



Data from the North Olympic Peninsula illustrates how complex the propagation of these waves are. It appears that Port Angeles is seeing the biggest wave heights (though not by much), suggesting that the Strait of Juan de Fuca may be somehow funneling energy propagating from the Pacific. In Westport amplitudes are smallest:



Moving up the coast La Push saw some slightly larger waves:



but in Neah Bay they initial waves were a bit smaller:



The hydrograph from Port Angeles suggests that we are in the middle of the wave train:



and finally the most recent data from Port Townsend suggests that the wave is just reaching there, and has attenuated since reaching Port Angeles:

"King" tides in Edmonds, WA

An increasing probability of coastal flooding due to extreme high tides is one of the impacts of climate change in the Pac NW that we should consider. Here is a brief from today's Seattle Times regarding Edmonds preparations for expected high tides this weekend.

They mention in the paper that these "king" tides occur once or twice a year. The astronomical components of water level, controlled primarily by the relative position of the sun and the moon, do indeed combine a few times a year in such a way to produce extremely high (and low) water levels. Usually communities are relatively well prepared for the astronomical component of king tides, since they are regularly occurring and predictable.

The trouble for coastal communities occurs when some climatic or oceanographic event adds more water on top of the already high water levels. In this article the additional water is attributed to precipitation. Sea level rise will also add elevation to the peak water levels. In Puget Sound strong winds in the Pacific Ocean can also push water into the inland sea, raising the overall water level. Finally, we must consider that waves (even the wind waves generated in Puget Sound) can increase the destructive force of high water.

Much of our region is still in a pattern of post-glacial rebound, which ameliorates to a degree the influence of pure or "eustatic" sea level rise. Relative sea level in some parts of the Salish Sea is, in fact, dropping rather than rising (Neah Bay, for example) because of high rates of tectonic uplift. We also have a tendency to think of sea level rise in rather simple terms, as a bit more water filling the tub. The real question for our region is a bit more complex: "How will the probability of occurrence of "king" tides increase over the next 10 to 100 years as sea-level increases and storm and precipitation patterns change?". In other words, will we see more articles like this one, in more places, over the coming years?

Its been quite a while since my last past, but I want to use this story, passed along by another of Gary Griggs' students, as my inspiration to get rolling again. Some time ago I wrote a short post about the frame of an old boat exposed by erosion on the coast of SW Washington. As a fan of history AND coastal dynamics I find the combination of the two irresistible. But, in reality, Washington's post-"discovery" history can hardly be called history when held up to the timescales that most of the world lives amongst. This has been glaringly apparent to us on travels to Paris, Mayan or Aztecan Central America, Ankor Wat in Cambodia, or even the Tidewater region of Virginia. And that is exactly what makes this story so cool. In this case the exposed artifacts are 2000 years old, from the Middle East.

Coupled with the recent release of a new theory on a possible route out of Africa for early Homo sapiens this particular story brings home that the study of coastal dynamics - including sea-level history and sedimentation, can not only help us plan for our future, but also can reveal our past.

An Ode to the Fisher Price Baby Jungle Gym

It is turning out to be an invaluable scientific tool. I am now at home full-time, caring for McHenry while Christine returns to work. Productivity has definitely tumbled, but I am starting to notice it picking up again. AND I get an extra hour or more of writing out of the day thanks to the Fisher Price Jungle Gym thing. He digs it, and therefore I dig it, despite the fact that it needs batteries (usually an automatic deal-killer in most baby toys).

My main focus at the moment is writing what I will hope will be my first published paper. I've also simultaneously decided that I can no longer go another day only reading nerd books, so I've started doing a bit of night time normal person reading again. At the moment: Log of the Sea of Cortez. This is my second reading, having first picked it up about 10 years ago. Last night I read the following apropos passage:

"It has seemed sometimes that the little men in scientific work assumed the awe-fullness of a priesthood to hide their deficiencies, as the witch-doctor does with his stilts and high masks, as the priesthoods of all cults have, with secret or unfamiliar languages and symbols. It is usually found that only the little stuffy men object to what is called "popularization", by which they mean writing with a clarity understandable to one not familiar with the tricks and codes of the cult. We have not known a single great scientist who could not discourse freely and interestingly with a child."

I feel myself sometimes slipping off of the precipice into the abyss of the particular language of my disciplines, and Mr. S. delivers here a timely reminder.

Face to Face with a tsunami...

but it wasn't that big (though it was my first tsunami that I've actually observed). Yesterday I roped Christine and my mom, with mchenry in tow, into heading down to the beach where I had the idea that I could collect a bunch of video of the chilean tsunami impacting the local beaches - and then speed it up (so one could actually see something). Sadly, the battery in my video camera died after only 14 minutes. But I've taken what I did collect and compressed it into about a minute of video. And, in the end, I am really not sure that you can make anything out, though the tsunami WAS evident on the beach as we stood there and watched. The harbor entrance in particular would turn into a river each time the trough of the wave impacted the shore (we watched for perhaps an hour, in which time maybe two wavelengths hit). As usual, I was curious to see the tsunami signature in the P.A. tidal gauge - and there it is. Surprisingly, the amplitude of the wave was about 25, same as was recorded in San Francisco, though the period of the wave appears to be different in the two locations...
and while the tsunami hitting our coast was more of a novelty, I think it is important to recognize that this one, like so many before (and the earthquake that generated it), took lives. My heart goes out to those that are still suffering as a result...

I may be starting to enjoy posters...

A few posts back I took the opportunity to poke some fun at one of the three legs of the scientists communication "stool". The poster is a much used tool - sort of like the first step in communicating progress or results of a study. Yesterday I presented my second poster at a conference in Washington...but I wasn't there. My co-author, a student from Peninsula College (also a boat-driver for the US Coast Guard) stood at the poster and reported that people were interested in the work. Always good to hear. Though to be honest he thought the interest was more in the method (putting RFID tags into rocks) than in the sedimentological ramifications of our research. Oh well - I totally get it.