Tuesday, December 30, 2014

Reverse Micro Climate in the Olympics

I got to be out in the weather the past few days. A bit chilly and the vegetation was brittle, but sunny! Typically flexible branches that I grabbed were brittle due to the freeze and the ground was crunchy underfoot.
On Monday I observed a reverse of a local mirco climate. There were clear skies everywhere in  western Washington with the exception of the north slope of the Olympic Range. The northeast wind was causing uplift and cloud formation on the north side of the range. Perhaps not a great picture but it is a localized weather/climate event I always enjoy seeing - reverse of the rain shadow that is more typical of this area.
View of the clouds forming out of clear skies as the north wind lifts over the Olympic Range looking west from Discovery Bay

Sunday, December 28, 2014

More Notes on Tsunami Policy

A bit more of a follow up on my previous two posts: tsunami-policy-newport-Oregon and geologic-consent-and-civilization.
Chris Rowan contemplates the 10 years ago Sumatra Quake and tsunami (highlyallochthonous/sumatra-10-contemplating-the-power-of-tsunami)  and put up this USGS image of giant quakes.
It is a good reminder of the past and how much we have learned about giant subduction earthquakes and tsunamis since. It is also illustrative as to why there was a lag in subduction zone earthquake policy and planning in the Pacific Northwest. Outside of a few locations, these risks have been greatly under appreciated or in many cases completely unknown. And even where there was an appreciation, the mechanics were a complete mystery.

Giant coastal quakes and tsunamis were well known to afflict Chile, Japan and Indonesia. But the cause was not known and there was essentially no correlation between those far off places and the Washington State coast.

The Alaska quake of 1964 was important in that it took place shortly after the new concept of plate tectonics had become part of our understanding of how geology worked. As Rowan points out George Plafker's post 1964 Alaska Quake research radically altered our understanding of great quakes, subduction zone seismic events, and tsunamis. The great quake in Chile shortly before the Alaska event also impacted those interpretations.

What this meant for Washington State was that we began to realize that the Pacific Northwest coast was fronted with a tectonic alignment that matched other places around the world that had a history of giant earthquakes and tsunamis.

But the table above hints at what might be the cause of complacency and a lag in understanding and planning; there are big gaps between these large earthquake events. We went for 40 years without a mega thrust 9 earthquake anywhere in the world. Hence, it was hard to appreciate the destructive forces. In addition, the Pacific Northwest had no history of these events (Excepting the oral histories of First Nations Peoples). There was a debate of sorts for some time that giant mega thrusts may not be a risk here as we had no history of these sort of events.  

Brian Atwater went to the outer Washington State coast looking for the features observed in Chile and Alaska and found evidence of mega thrust faulting and over time he and many others have found clear evidence that giant quakes and tsunamis are part of the Pacific Northwest coastal landscape (see HERE for one site of that evidence). Atwater and others work shows that we have mega thrust quakes like Chile, Japan and Sumatra (http://pubs.usgs.gov/pp/pp1707/.)

From a policy and planning perspective, we have some catching up to do with this relatively new understanding. The USGS and State Geology divisions in Oregon and Washington  have been working on educating the public and providing hazard maps. University researchers have made many advances in our understanding.

Emergency Planners have recognized the risk in most communities, and that recognition is evident with efforts to minimize the deaths and deal with the after event challenges. A lot of those efforts began before the big quakes in Sumatra and Japan. But in many communities emergency planners will tell you a lot more will need to be done with the populations already living in harms way. Oregon State governor has put $100 million into seismic safety in the next budget cycle. Plans are in the works for building escape centers on schools in danger zones in Washington State.

Then there is the development planning part of this equation. The fact that Oregon State University would be planning and advocating for a major structure within a known significant tsunami hazard zone does raise questions as to local, state and federal policies regarding funding development that we know will be destroyed catastrophically. While state and federal dollars are transferred to in-danger communities to mitigate the risks for areas of communities in harms way, more thought should go into where development investments are expended.

As atquake notes, "At the very least, learning from Sumatra (and Tohoku) is simple: don’t build high occupancy buildings in a tsunami zone, particularly when they’re on fill and have limited evacuation options". This is a policy position Washington State and Oregon State need to adopt.

For the thoughtful discussion of this policy issue as shout out to
Chris at http://all-geo.org/highlyallochthonous/,
Lockwood at http://outsidetheinterzone.blogspot.com/,
Chris at atquake
and Oregon Public Radio.


Saturday, December 27, 2014

Tsunami Policy: Newport Oregon and Oregon State University - What will they do?

Oregon Live noted that that the head the Oregon State Department of Geology and Mineral Industries sent a letter to Oregon State University about tsunami hazards in Newport, Oregon (oregonlive.com/state geologist_warns).

The letter is consistent with Oregon State Law 455.447 (oregonlaws.org/ors/455.447) which states "Developers of new essential facilities, hazardous facilities and major structures described in subsection (1)(a)(E), (b) and (c) of this section and new special occupancy (my emphasis) structures described in subsection (1)(e)(A), (D) and (F) of this section that are located in an identified tsunami inundation zone shall consult with the State Department of Geology and Mineral Industries for assistance in determining the impact of possible tsunamis on the proposed development and for assistance in preparing methods to mitigate risk at the site of a potential tsunami. Consultation shall take place prior to submittal of design plans to the building official for final approval."

Oregon State University is planning building a major marine studies facility within a tsunami hazard area. While it is likely not possible to build all necessary facilities associated with marine activities outside tsunami hazard areas, the concerned building is for up to 500 people in a known tsunami hazard area and includes classrooms, labs and offices. The 500 number is the threshold for special occupancy structures per the Oregon State Law.  The facility is within a hazard posed even by a distance source tsunami and a local tsunami generated by the subduction zone along the Oregon coast (and Washington and northern California). The estimated wave height from a local subduction event is 43 feet. With between 10 to 15 minutes to get to higher ground, the race will be close for some given the one half mile distance that will need to be covered.

This image is modified slightly from the original. I had missed the hill small hill that was closer to the science center site - Lockwood (see comments) clarified the escape route.

 It will be interesting to follow how this consultation will proceed. Newport has been an enthusiastic community for marine sciences and was awarded the NOAA facility 5 years ago much to the dismay of Washington State after years of NOAA being in Seattle and the ever hopeful Port of Bellingham that took a crack at attracting NOAA. I would note that despite the NOAA contribution to tsunami hazard mapping, the 2-story NOAA office building will also require a rapid one mile evacuation.

It might be worth taking a look at the view of a 43-foot tsunami wave encountering an essential public service building:

The tsunami surges toward the roof of the three-story disaster management building of the Minami-Sanriku town office, in a photo captured by Nobuo Kato, at 3:34 p.m. on March 11. (Photo by the town of Minami-Sanriku)

Read Nobua Kato's story HERE

Tuesday, December 23, 2014

Geologic Consent and Civilization: Rethinking Durant's Quote

"Civilization exists by geological consent, subject to change without notice." - Will Durant in What is Civilization?, Ladies Home Journal, January 1946

I have had the opportunity to give a few talks the past few months and have been closing with this quote from the historian Will Durant.

Historically Durant's quote certainly is applicable, and the quote is a nice nod to the importance of geology in shaping civilization. Certainly there have been civilizations that have been shaped and in some cases ended due to geology. The shaping of civilization by geology has been both subtle and at times dramatic. 

That said, I think geologists and civilization should focus on the "change without notice" part of the quote. While our modern civilization may not be able to precisely predict civilization changing geologic events, I would argue geology does give us notice. How we, as a modern civilization, respond to geologic notice is a measure of our success as a civilization. We have moved beyond, or we should have, being caught unaware of geologic processes. 

A measure of the success of a civilization is to respond and plan for what geology change will take place. A hard thing to do at any government level be it local or global. 

Monday, December 22, 2014

Nohokomeen Glacier

Last summer I had a nice view of the north side of Jack Mountain in the North Cascades.

Jack Mountain viewed from the south slope of Desolation Peak

Jack Mountain viewed from Ross Lake

Jack Mountain's north slope is covered by the Nohokomeen Glacier. There are small glaciers to the east of Jack Mountain, but this is the last of the larger glaciers that extend down to below 6,000 feet. The combination of the height of Jack Mountain (9,066 feet), its location downwind of the gap in the mountains created by the Skagit River and the north aspect of the slope have allowed the glacier to form and remain. Otherwise, this area of the North Cascades is not nearly as glaciated as the peaks further to the west. The range becomes progressively drier to the east and hence the number and size of glaciers this far east in the range is significantly less than areas to the west, and the elevations of glaciers becomes limited to higher peaks and ridges only. 

Blue line marks the current extent of the glacier 
The glacier terminus has retreated approximately 500 feet in elevation from its position when the topographic map was published

The available Google earth images suggest that the retreat since 1998 has been minimal.

Blue line marks the extent of the ice terminus in 1998 and is imposed on the 2013 image. 
The Nohokomeen Glacier is not among the the glaciers that have been routinely monitored and measured by the National Park.

Friday, December 19, 2014

Dirt and Views from Mid December Field Work

A bit short of content and posts due to work and travel and field time. The last two days were classic western Washington mid winter field days - a bit wet, a bit windy and the days are really short. Work was a mix of figuring out dirt and with cloudy views.

Southern tip end of the Bolton Peninsula with
Quilcene Bay on the left and Dabob Bay on the right

Oxidized outwash and drift

Where did this pebble come from? Non Olympic source

Another cut slope - compact glacial advance outwash

Test pit digging to confirm or disprove a theory

Drift plain west of Port Townsend

Looking down a 300-foot bluff and recent slope failure along Strait of Juan de Fuca

Wind riffling the water on the Strait

Whidbey Island, San Juans and Mount Erie 

Monday, December 15, 2014

SR 530 (Hazel/Oso) Landslide Commission Report

Washington State Governor Jay Inslee set up a landslide commission to review the Hazel/Oso Landslide. The commission report came out on December 15: SR530 Landslide Commission Final Report.pdf
One of the recommendations is to further fund landslide hazard mapping, "The SR 530 Landslide highlights the need to incorporate landslide hazard, risk, and vulnerability assessments into land-use planning, and to expand and refine geologic and geohazard mapping throughout the State. The lack of current, high-quality data seriously hampers efforts under the Growth Management Act".
The Washington State Department of Natural Resources has already developed a robust budget request for funding mapping efforts that will be submitted to the legislators this winter. It is a tough budget year. Where landslide risk and costs associated with it fall will remain to be seen.  

Sunday, December 14, 2014

Politics Sunday: Cromnibus Notes and Torture

I have been a bit into deep tunneling into code language and how it relates to geology. The consequences of a single sentence or word associated with geologic risk.

So excuse the politics, but I did have a political era in my past that still comes out at times.

I do enjoy political drama and Cromnibus has provided some. The best part are the riders that are attached to get certain things done that would never get done unless done in this manner. Depending on one's perspective it is not all bad or alternatively it is horrible.

Sarah Kliff explains how Republicans and Democrats worked together to solve an Affordable Care Act taxing problem in a very wonk loving post cromnibus-obamacare-blues-mlr. So Cromnibus provided deep cover for getting something done that our political tribalism would otherwise never allow.

Financial wonky Senator Warren points out much of our political positioning is pure rhetoric. How many Tea Party backed politicians would support using tax dollars to bail out big banks?

Then there was the Torture Report. Yes, our leaders supported and encouraged torture,  "I'd do it again in a minute." - Dick Cheney on EIT. Call it what it is; Enhanced Interrogation Techniques (EIT) is torture. And our country did it. And the Senate report shows that it did not provide the results the supporters of torture claimed. But I am sure the torture supporters will continue to claim that it worked. Perhaps they have no choice as it would otherwise mean pushing humus up a victim's ass accomplished nothing but torture for torture sake. And keep in mind that some of the torture victims were completely innocent and had nothing to do with terrorism. Matt at Vox points out we should call it what it is eits-are-torture. Words do matter.

Back to my own policy word selections.

Friday, December 12, 2014

Snow and Spire: Just Right for the Season

A bit of an opinion and a strong one at that: There is no better "coffee table" book featuring the Washington State Landscape than Snow and Spire. Washington State has been blessed with some remarkable photographers that have been inspired by our landscapes and have successfully passed that inspiration on to others.  

The images in Snow and Spire surpass words. There is one image in the book of a place I had once been. I recognized the location immediately. I had gone there alone. On that trip I did not see another human being for a week. At the time I could not believe there was such a landscape. In my memory the sites I saw fall into the border between reality and dreams. It was a foolish dangerous trip. Get the book - it is a much better way:

I came across this video of John's ventures. Besides the wonder of the images, John has been making some significant contributions to understanding the glaciers in the North Cascades.

Snow and Spire - The Aerial Photography of John Scurlock from Chris Newley on Vimeo.


Thursday, December 11, 2014

Update on Washaway

With winter high tides combined with very stormy conditions, the Pacific Ocean is taking some more of Washington State along with a few homes at Washaway Beach kirotv.com/videos/news/watch-it-ocean-undercut-home-on-washaway-beach/vCkfR/.

This has been an ongoing erosion problem that I wrote up after a visit in 2010.



HS also has a set of posts http://gravelbeach.blogspot.com/search?q=washaway

Wednesday, December 10, 2014

Egan Chasing Shadows


I have accumulated some books on the Washington State Landscape that deserve a write up hence wallula-gap and geology-of-san-juan-islands.
Timothy Egan took on Edward Curtis. Curtis moved to Washington State and started a photography business in Seattle. His fame is the photographs he took of First Nations peoples. Curtis' genius was recognizing that we would soon loose multiple cultures unless he captured those cultures before they were gone. He was not the only one to recognize this need, but he may have done more than anyone else capturing the shadows of the cultures that once inhabited our landscapes before they were gone.
Egan is one of our own and his perspective is appreciated. And the book manages to capture the capturer of shadows and another time so easily forgotten of the early days of the second nation in the Pacific Northwest and what is now Washington State. I particularly liked learning more about Asahel Curtis, Edward Curtis' brother as I have used his photographs in my own work. A. Curtis captured different images - numerous of geologic and historic importance and some that captured the shaping of our current landscapes.
I know that I have been frustrated at the loss of understanding of what once was the Pacific Northwest, but Curtis captured at least a part of that in his images and Egan gives this important work an added perspective. 

Monday, December 8, 2014

Wallula Gap Book

I have had this book for a couple of years. Where the Great River Bends is a compilation of natural and historic essays on Wallula Gap.

I have the personal opinion that the Gap may be the most underappreciated landscape features in Washington State. This book of essays on the geology, plant communities, and history further enhanced my own appreciation of this remarkable landscape. Good geology including how the gap was initially cut, not by the Columbia River, but by the Clearwater River - currently a tributary of the Snake. The river in the gap is slackwater from McNary Dam downstream of the gap. The book does a great job of explaining the secondary consequences of the river no longer have the massive floods through the gap followed by much lower water - not just on the river but on the surrounding uplands. As windy as the area northeast of the gap is, the dust and blowing sand are much diminished from the old days. Pacific Northwest history passed through the gap from Lewis and Clark, Hudson Bay Company traders, naturalist David Douglas and explorer John Thompson.  Today a great deal of commerce passes through the gap via barge and the railroads that line both sides of the gap. This is the route of the recently famous very heavy Powder River coal trains on the way to the coal port in British Columbia.

In a different era I ran and hiked the rim of the west side of the high cliffs above the Columbia River at this water gap accessing the area via back roads from Kennewick. It was one of the pleasures of living in Kennewick to have such a landscape nearby.


Sunday, December 7, 2014

Old Skagit Channels and a Tributary Alluvial Fan

Before the weather shifted back to wet, I had a venture up the Skagit Valley in an area of old river channels, old river terraces and a dissected alluvial fan. One of the old river channels on what is now a terrace above the river flood plain was ice covered.

The lower end of the channel showed that water had been flowing out of the channel prior to full freeze up. The valley in the background is a tributary stream valley to the Skagit.


There was lots of water flowing in this old Skagit River channel on the flood plain proper. This water was flowing through an abandoned meander loop that had been abandoned by the river but now was occupied by a tributary stream coming off the valley side. Note that rapid water flow is flowing through trees and with the cold weather this water flowing through tree stands was not the result of high water. This feature suggests the creek had relatively recently changed course.

Stumbling about a forested flood plain with lots of water has its pleasures; the above observations were secondary to my field excursion. To get a better handle on the flood plain, old channels, terraces, and the creek a view of a DEM of the area clarifies understanding of the landscape.

DEM of Skagit Valley
Red line roughly marks the outline of the alluvial fan of the creek and blue marks the creek route.
Skagit River is on the north side of the valley on this river reach

The wide meanders and old channels of the Skagit are readily visible. What is also apparent is that the Skagit River took a few bites out of the northern, distal part of the creek's alluvial fan. A small secondary fan has formed where the creek encounters the old river channel. A stream course change on this secondary fan has directed the creek into a slightly different route now through the trees shown in the image above.

I did not mark the Skagit flood plain the above image. Most of the meander bends and old channel traces on the south half of the valley are now well above the flood plain level and are level terrace areas bound by flood plain abandoned channels or in places the river itself. This indicates that though the river has a meander component in this reach, it has still been down cutting. This reach of the Skagit is a broad section of the valley that continues downstream to the Sauk River. Below the Sauk the river enters a much narrower reach where it is incised down through a thick section of glacial sediments including a high terrace with kettles.

DEM of Skagit - Sauk confluence
The narrow reach to the west cuts through glacial sediments
Upon my return from exploration of the flood plain my new friends on the terrace above the flood plain came over to greet me.

Saturday, December 6, 2014

Failed Canal Project Through Beacon Hill

David Williams has a bit on a failed canal project in Seattle's past south-canal-beacon-hill. David points out that the project got started and bit into the side of Beacon Hill where Columbia Way now traverses up Beacon Hill from Spokane Street and Interstate 5.

Here is what the LiDAR looks like:


Friday, December 5, 2014

Ode to Past Explorers and Future Explorers: Wander and Wonder

 Ah, I can be a romantic at times. This video was a labor of love by Erik Wernquist that built on the words of Carl Sagan describing the inherent desire to explore and wander. Let us understand our own planet and reach out to our own wondrous solar system and then beyond. We should wander and wonder. And it is a team effort beyond any one human.

Thursday, December 4, 2014

Geology of the San Juan Islands


Ned Brown has provided geologists and anyone else interested in the geology of northwest Washington State an up to date book on the geology of the San Juan Islands (and non San Juan Islands Fidalgo Island). And if your interested in deciphering accretion tectonics anywhere, this book should be in your library. Ned has put together a clear compilation of the San Juan Island bedrock geology as it is currently understood. He also provides a good overview of how geologists extract stories out of rocks from microscopic study of minerals to zapping zircons with lasers. The book is full of excellent graphics and ends with some guidance to good outcrop sites.

I do a fair bit of geology work in the San Juans. For many years I have been heavily relying on 1975 maps of the San Juan Islands produced by Joe Vance and John Whetten published in Geology and Water Resources of the San Juan Islands (Russel, editor, 1975). My copy of that work is very dog eared.

I anticipate that my copy of Ned's book will become dog eared as well. The book already answered a question I had about an outcrop at the Lopez Island ferry landing and another outcrop at the north end of Blakely. 

Saturday, November 29, 2014

Zintel Canyon Trash Wrack

Zintel Canyon is a ravine incised down through a thick ice-age flood terrace in Kennewick. The stream has a rather large drainage area in the Horse Heaven Hills, and poses a bit of a flood risk to the neighborhoods below where the canyon opens up. The Army Corp of Engineers constructed a flood control dam zintel-canyon-dam where the canyon passes through one of the northern ridges in the Horse Heavens.
Downstream where the canyon opens up onto the low ground between the canyon mouth and the Columbia River the creek enters a large culvert to pass under streets. A trash wrack to catch debris has been built at the culvert entrance. 
Trash wrack at 7th and Vancouver

A trail has been constructed up the canyon. The year round stream with thickets of brush and Russian olive and cottonwoods is an oasis in this area with less than 8 inches of rain per year. As urbanization has taken place it has become an oasis of a bit of wildness in the urban landscape.

The flow in the stream is enhanced by recharge by irrigation water and the City of Kennewick has been working on schemes to further recharge the aquifer. At the lower end of the stream near the Columbia River Kennewick has drinking water wells. 

Wednesday, November 26, 2014

Safe Travels and a Bit More Music

The Thanksgiving tradition blog post with Lisa Hannigan. Also some Angus and Julia Stone. Perhaps a bit of a melancholy theme to this selection.

Tuesday, November 25, 2014

Slope Fractures Before the Nile Landslide of 2009

DEM of Sanford Pasture Landslide
A landslide on the Naches River west of Yakima in 2009 diverted the Naches River and closed a State Highway. That slide was a very small part of a much older ancient massive landslide, the Sanford Pasture Landslide. The part that failed was a small section on the northwest end of the larger ancient landslide complex.

Sliding Thought Blog put up a nice post about the Sanford Pasture Landslide HERE. Alas, the posts at Sliding Thought have been discontinued - sensitive higher ups in the agency depriving us landslide wonks of some excellent insights.

When pulling some images together for a talk I decided to include a note on the Sanford Pasture Landslide simply because it was so large. It surpasses the huge Church Mountain Slide in Whatcom County and is much larger than the more famous Bridge of the Gods slide in the Columbia River Gorge. When pulling historic aerials together, I noted that the set of historic images captures the development of the fracture that began to form several years before the slide. The fracture was noticed by the Department of Natural Resources prior to the slope failure.

Pre facture image from 1998 with rock quarry in lower central part of image

Fracture can be seen on the steep slope on upper right in this 2009 image

2010 post slope failure with diverted river
WDOT has a lengthily post slide technical report that compiled lots of information and provides good figures and the geologic interpretations as well as assessment of the current stability of the slide area (NileValleyLandslidegeotechnicalreport.pdf).

Sunday, November 23, 2014

Wetlands, Farmland and Drainage on the Nooksack Flood Plain

Before our November sunny break I headed north to Lynden and noted the water logged Nooksack River flood plain south of town. 
Nooksack River flood plain south of river and south of Lynden
The river was not flooding. The source of water standing over acres of land was the result of lots of local rain and poor drainage. The silty soils, high ground water and subtle topography cause water to accumulate in the fields.
The DEM of the area shows the problem of drainage on the flood plain - it is essentially uphill to the river.
DEM of Nooksack flood plain

The river is flowing from east to west and is the dark olive green sinuous line in the image. The straight tan line on the west half is Guide Meridian Road. I took the watery picture from my car looking east south of the river. Note that there are broad olive green colored low areas well back from the river both north and south of the river. The two south of the river are linked to the river via narrow streams and ditches that are barely discernible in the image. Otherwise these two low areas are separated from the river by a subtle but definite uphill slope. Each color shade corresponds to 1 meter in elevation.

Without the ability to keep the narrow ditches and stream connections to the river these fields would turn into swamp land or wet lands depending on your word selection. Water on the fields is not a problem in the winter, but if the fields remain wet deep into late spring, the farm land will be of little value.

The Growth Management Act requires counties to protect wetlands; however, there is a recognition that agricultural land should be protected as well. Under the local GMA required regulations Whatcom County critical areas regulations for wetlands allow the maintenance of drainage channels on farm lands. But the work on these drainage channels still requires State permits from the Washington State Department of Wildlife and the work requires a farm conservation plan.

Saturday, November 22, 2014

Fault Y in the Kittitas Valley

Waitt (1979)  identified three faults cutting across the Kittatas Valley. While the faults do off set Pleistocene sediments of the Thorpe Gravel, no definitive off sets have been identified within younger (last 11,000 years) sediments. The off set of the Thorp Gravel alluvial plain north of Ellensburg can readily be seen in the DEM: 
Fault off set is an east-west fault cutting across the center of the DEM with up to the south 

This DEM has the fault marked in black

There are two other faults. One is closer to Ellensburg and the other towards the north.

The aerial view of the the fault shown above via Google earth:

Friday, November 21, 2014

Random bits of Whidbey Island History

I was digging a bit into the history of the water front area of Oak Harbor related to a project I was working on and came across a couple of unrelated but interesting bits on the history of Whidbey Island by David Wilma at http://www.historylink.org.

"The settlers learned to dose deer carcasses with strychnine and the wolves eventually became extinct on Whidbey Island."

A good reminder as to how wide spread wolves were and that returning to some natural condition ecosystem may not be so easy without a top predator keeping the deer population in check.

"Sea Captain Edward Barrington and Charlie Phillips opened a trading post at Oak Harbor in the early 1850s because he did not want to paddle a canoe two days to Olympia for supplies. Barrington became an important intermediary between whites and Indians when disputes arose. Local legend holds that Barrington, a large man with red hair and beard, confronted a group of raiding Northern Indians. Barrington showed the invaders his fear of no one by destroying a nearby Skagit burial canoe and placing a skull on a stick. He then began to dance and then rushed the raiders. They fled in panic and Barrington saved himself and local Skagits from death and enslavement. Northern Indians never again bothered Oak Harbor."

This legend does conjure an entertaining visual impression. What is definitely true is that northern Indians did routinely raid this area and had been for some time including in the 1850s. One of these raids near present day Port Gamble likely played a major role in the outcome of the Yakama War. The U.S. Navy fired on the invading Indians. North Puget Sound and Washington tribes were not receptive to the idea of joining the Yakama War in part due to appreciation of defense from the invading northern Indians. Barrington may have played some role in repelling an attack, but cannon fire from the U.S. Navy likely put an end to the northern Indian raids.   

Thursday, November 20, 2014

Notes on Tree Rings, and Old Forests and an Old Terrane on Orcas Island

I came across a couple of blow down trees that had been cut in order to reopen the road that they blocked. Both trees were Douglas fir and the site was on the dryer, western part of Orcas Island. Both trees were growing in very thin to almost non existent soil over Turtleback Complex bedrock. Knowing how old trees are can be helpful in evaluating slopes. In this case the trees were not really important for that purpose, but for other reasons I was curious about the age of the trees so I did tree ring counting.  

As can be seen the rings were very tightly spaced particularly that outer band shown above, but a mid section band was also very closely spaced. I ended up with a count of 220. The tree was much older than I had initially expected at first glance. The modest size by old age reflects the rather harsh growing conditions. The tree was growing out of bedrock with very little soil. Something to consider when trying to estimate the age of trees by girth alone. A few weeks ago I was in a forest of much larger Douglas fir and that stand of trees was less than 60 years old.

No much soil under those roots.

The forest where this tree was located is nearly all Douglas fir, but the trunk sizes varied suggesting a very mixed age. I did observe a few madrones which would suggest the forest canopy may have been more open in the past, but this forest was fairly open even now. Underbrush was very thin and it was easy to move through this forest with a moss dominated floor and very thin brush. All over very thin soils and fractured hard bedrock and solid bedrock - not much in the way of glacial related sediment at this location.

Take a close look at the tree lying on the floor of the forest. This is an old blow down, but it is still very much alive. Two of its limbs have become leaders growing as straight trees out of the trunk. This is a Douglas fir feature I have observed at several other locations on Orcas Island including some spectacular examples on Turtleback Mountain (selection-of-trees-on-orcas-island).

Elsewhere on Orcas I have observed very massive Douglas firs much bigger the 220 year old tree. Hence, I am now very curious about the age of those giants some of which are located on sites with very harsh growing conditions.

This blow down tree has a bit of a story to tell. One thing it shows is that at least at this site the area was not clear cut logged. Historically the San Juan Islands were known for not having particularly good timber relative to much of the rest of western Washington. This particular blow down tree seemed to be straight and not very limby. Perhaps its inland location and challenging site to move logs preempted this forest from being clear cut. The tree also had survived pre European/American land management - it had not been burned by fire. I did not observe any indication of past burn scars anywhere in this particular forest stand.

From a forest species perspective, the dominance of Douglas fir at this location dating back over 200 years is a bit different than nearby forest stands where lodge pole pine (locally called shore pine) are well represented as well as stands of junipers and oaks.

As for the bedrock of this forest. The rocks are part of the Turtleback Complex named for Turtleback Mountain on the west side of Orcas Island. Not supper exciting rocks to look at, but these rocks are very old and have a story to tell for those willing to extract the story out of them via microscopic mineral work and careful measurement of element isotopes.

A bit of Turtleback with the edge of a rock hammer on the right

Turtleback with faint mineral gneiss-like mineral alignment and green minerals (epidote?) with Douglas fir needle for scale.

The Turtleback Complex is one of several tectonic terranes in the Northwest Cascades System-San Juan mélange. Units within the mélange consist of a wide variety of low-grade to high-grade metamorphic rocks of various ages juxtaposed along now extinct tectonic fault lines. The terrains are slices of ocean floor, island arcs and possibly in some cases slices of terrane broken off of other continents and then accreted to the North American western margin via plate tectonic movements.

The Turtleback Complex is the oldest terrain in the San Juan mélange and has been correlated with similar very old rocks in the Northwest Cascades, the Yellow Aster Complex. Vance (1975) suggested the Turtleback was continental. The Turtleback contains a range of igneous rock types with intrusive cross cutting relationships, and I have found a fair bit of variety across the various locations I have encountered the Turtleback. Age of the intrusive rocks have been reported ages ranging from 554 Ma to 460 Ma (Whetten and others, 1978 and Brandon and others, 1988). This a very old terrane and plate tectonics does have some mind bending puzzles and correlating long traveled old terranes with their homeland will take considerable work. 

Sunday, November 16, 2014

BNSF Railroad and Unstable Bluffs near Bellingham

In late 2012 and early 2013 there were close to 100 shallow landslides that closed the rail line between Seattle and Everett, Washington due to wet weather and slopes above the railroad tracks becoming repeatedly saturated (railroad-landslide-closures). There was even a landslide that hit a moving train during that period.

The rail line just northwest of Bellingham has not been closed by landslides, but faces a significant risk of landslides in the future as the railroad track runs along the top of a steep eroding shoreline bluff.  

Its worth enlarging this picture to see the failure scarps at several places on the slope as well as a drain pipe installed to reduce water on the slope. 

Railroad without much space 

I routinely assess steep shoreline bluff slopes and recommend setbacks for homes from the top edge of steep shoreline bluffs - this section of railroad would not conform with recommended setbacks. But like homes close to the edge of a potentially unstable slope, the view is great. And I have enjoyed the view from the train while heading up to Vancouver, BC.
 The beach is very narrow at least along parts of the bluff and high water routinely reaches the toe of the slope causing erosion.
Shallow surface failure on bluff

The bluff is underlain by unconsolidated late ice age deposits of silt and clay and sand and gravel. The small slide shown above is the result of the toe of the slope being eroded by waves and then the slide area slowly working its way up the slope.

This reach of shore is exposed to south and west winds and has a large enough fetch and orientation such that large waves can be generated and combined with large storm surges.

A future challenge for the railroad.