Thursday, December 14, 2017

Taking a Break at Sinclair Inlet

I make it down to Sinclair Inlet for work a few times every year. The inlet is across Puget Sound from Seattle. Bremerton is on the north shore and Port Orchard is on the south shore. I took a break and walked out on the public dock in Port Orchard. The dock is a relatively new dock for public use.

View back towards the slopes of Port Orchard with the waterfront Cheers Bar and Grill

An interesting aspect of Port Orchard is it provides great views of the Naval Ship Yard. It is a busy place with ships lined up for maintenance and repairs. I always enjoy hearing the periodic revelry carrying across the water.

Saturday, December 9, 2017

Where the Cascades Touch the Sea

A northwest Washington point of pride in Whatcom County and Skagit County is noting that area on the border of the two counties is where the Cascade Mountains touch the sea.

Where the mountains touch the sea
Chuckanut and Blanchard Mountains on the right horizon
Lummi Peak just right of center
Mount Constitution just left of center

A range of low mountains extends west of the North Cascades in the area and reaches the Salish Sea. The range extends out into the San Juan Islands. The ridges and summits are relatively modest with summits near the water just under 3,000 feet with higher ridges inland and lower summits in the islands. Never the less the range forms a belt of rugged landscape that cuts across the otherwise continuous north-south Willamette-Puget lowlands that extend the entire length of the west side of the state.

Interstate 5 weaves through the range through a narrow low gap between Skagit County and Whatcom County. Another road, State Highway 11, or Chuckanut Drive, follows the coast at the base of Chuckanut Mountain along the shore of Samish Bay and Bellingham Bay. It ranks as one of the most scenic drives in the State and is a route I have never tired of. It also has lots of unstable slopes and rockfall hazards.

There is no formal name for the range and it really is a combination of uplifts and tectonics that overlap in a manner that does not brink out a distinct name. Locally the westernmost range that descends to the water at Chuckanut Drive and is passed across by I-5 is often called The Chuckanuts.

On a broader scale that incorporates the wider western extension of summits utilizes the term Northwest Cascades. I utilize that term more frequently as it gets at the distinct geology although extremely complex geology and can very reasonably be extended to cover the rugged peaks in the San Juan Islands. This more geologic term is extended to the east to the Straight Creek Fault, a major strike-slip fault with markedly different geologic units on the other side to the east where the core of the North Cascade Range begins.         

Wednesday, December 6, 2017

Vaccinium ovatum (Evergreen Huckleberry)

Coming across a berry snack while in the field in December is always a bit of pleasant diversion.

I do a fair bit of work on the east and north side of the Olympic Mountains. Vaccinium ovatum is not only common as an understory plant, it can be the predominant plant in some areas.

My sense is that the plant does like moist ground, but a good dry spell and warm summer air gives the plant an edge compared to others. The waxy leathery leaves suggest drought tolerance. The evergreen habit allows the plant to take in solar energy during the winter, another edge compared to plants that die back in the winter.  

Wednesday, November 29, 2017

Pedestals and Petrified Wood

Last week I was asked by an associate if I could send some geology pictures to a student. A rather broad request given the thousands of geology pictures I have in my picture files. What came to mind was perhaps a bit random, but deviated from my Washington State geology and geology hazards pictures.

During my time at Petrified Forest National Park I was fascinated by erosional pedestals formed by hard blocks of rock (in some cases the rocks were petrified wood) protecting much weaker underlying rock or sediment.

Petrified wood forming erosion pedestals 
Petrified Forest National Park, Arizona

Monday, November 27, 2017

The Skagit River Nibbles at Highway 20

The warm spell last week combined with rain and mountain snow melt brought numerous rivers up to near or just above flood stage in western Washington. The Skagit River took a bite out of a section of  Highway 20. Several pictures of the damage plus the high water associated with the damage were being circulated by agency and other up river folks. The email strings did not provide specific references to the photographers so I can't attribute as I would otherwise like.  

The location of the channel migration erosion is just upstream of the Cascadia Farm seasonal fruit stand for those familiar with the highway. The river has been hard up against the highway at this location and is within a river reach with wide channel migration bends and curves with a flood plain valley over a mile wide with multiple old channels upstream of the confluence with the Sauk River.

Thursday, November 23, 2017

Lisa Hannigan - Safe Travels (Don't Die) (Live in Milan)

This blog's Thanksgiving tradition almost got forgot.

It is a bit of wet travel in Washington State. Rather bizarre to see 67 F at 7:00 pm last evening in Bellingham.

Wednesday, November 22, 2017

The Big One: The Hypocenter Makes a Big Difference

Wirth and others (2017) presented various Cascadia earthquake scenario modeling results at the October GSA meeting in Seattle. I scribbled some notes during the presentation. Just where and how deep or shallow the rupture on the fault takes place makes a big difference on the level of shaking that will take place at various locations. By using the model combined with observations of deformation along the coast, this work is refining what various locations might expect from the Big One. Two scenarios presented were for a hypocenter off the central Oregon coast and another with the hypocenter off the northwest Washington coast. The shaking in Seattle would be stronger for the Oregon hypocenter due to how the seismic waves will propagate.

A press release associated with GSA talk provides video of the shake simulations: