A Quick Visit to Portland
Mount Saint Helens is only 25 miles as the crow flies from Portland, so we stopped by our southern neighbor for a visit. It was raining, so we opted for indoor activities.
World Forestry Center
The World Forestry Center is next to the Oregon Zoo, and it was a dry place to wait for our next stop to open. It turns out that it is a children’s museum. A new exhibit had just opened so we toured Siberia by train, China by boat, the Amazon by a tree-top crane, and…
South Africa in a 1960s International Harvester Scout. I was ready to go, but the engine wouldn’t start.
Someone left a 22 caliber rifle in this tree back in the 60s, and it became one with nature.
This fake evergreen tree extends to the ceiling in the middle of the World Forestry Center. There were lots of activities for children of all ages, so this is probably a good place to visit with the family.
Japanese-American Museum of Oregon
After discovering forestry around the world, we went to the museum.
JAMO is small, but very interesting.
The early Japanese immigrants lived much like the Chinese, whose accommodations we saw in a previous post. By the 1930s they had established themselves throughout the West Coast, especially the PNW. This is a representative display of a general store.
There were dentists and all the trades because, despite being legal residents–many of them American citizens–they were prevented from fully participating in the American dream.
They lived in nice homes, owned businesses, spoke English better than most of their fellow citizens, but…
There weren’t enough of them to overwhelm the government’s demographers (unlike the German and Italian Americans), so they were rounded up in a show of national security; they were shipped to places where, if they were lucky, they shared a room like this with their entire family.
The JAMO has a lot of documents to read, but I focused on physical objects because I forgot my “museum glasses”, which focus at six feet. You’ll need to visit the museum yourself to learn the true history of the Japanese-Americans.
One brave activist violated curfew after release from a detention center, and found himself in jail for nine months. He eventually won in the courts, but at a high personal cost.
This terrible injustice wasn’t as horrific as what was done to the Native Americans, but it was pretty bad. The U.S. government eventually apologized, in the 1990s, but that was little consolation to those Americans who lost everything during a period of national paranoia. Some of them actually received a few thousand dollars in reparations (I guess they used 1940s dollars, not adjusted for inflation).
Mount Saint Helens Revisited: Ape Cave
We made it to our destination (Fig. 2) and explored a rare lava tube at Mount Saint Helens. This lava was erupted 1900 years ago as part of the same sequence that destroyed the forest a short distance away.
A full discussion of this fascinating natural feature is available from Washington Department of Natural Resources.
Figure 1. This lava tube is a lot larger than the tree casts we described in the last post. This immense cavern, which is more than 2.5 miles long, was created when a single basaltic lava finger flowed over the landscape. The outer material cooled in the air and insulated the interior, like an oven, allowing the remaining lava to exit the end of the tube. This left a void to be filled by subsequent lava flows. According to the information displayed at the site, the entire eruption lasted about 100 days.
Figure 2. Ape Cave is presumably named after the first eruption sequence of Mount Saint Helens, dated about 40 Ka. I didn’t find an explanation for this confusion, but it might have something to do with the Bigfoot legend associated with Ape Canyon, not far away. At any rate, the lava tube is indicated by the square in (B).
This video captures the scale of one of the many chambers better than any image. My narration isn’t very technical.
Figure 3. These parallel ridges running along the bottom of the cave near its terminus are the remnant of the last flow to use this conduit to reach open air.
Figure 4. A block of basalt transported through this narrow passage became stuck where the walls of a previous flow almost meet, leaving it stranded. It looks like it partially melted into the walls, however.
Figure 5. This view of the ceiling reveals a joint pattern caused by cooling of the outer layer of lava. Several generations of fractures occur throughout the cave, created as individual flows cooled differentially.
Figure 6. This is the end of the tube as it exists today. Apparently, there is no modern opening; it probably collapsed during the last 1900 years.
Figure 7. As a retired sedimentologist, I immediately noticed the layer outlined by the dash lines. This looks like cross-bedding; the layer fills a depression below the line, and is truncated by an overlying flow. This is interesting because cross-bedding is associated with particles being transported by wind or water; how it appears in a lava flow is an intriguing problem–perhaps heavy minerals like pyroxenes and lighter plagioclase feldspar?
Figure 8. This is a good time to briefly explain how the ledges seen in Figs 1, 4, and 6, and the video, were formed.
Once the lava tube was created by cooling of the surface of the original flow, subsequent flows ran through, but didn’t fill, an insulated tube. Their surface was usually below the original ceiling. The coolest parts of this conduit would have been the sides (heat dissipates more quickly through older, cooler basalt than the superheated air above the lava river). Thus, ridges like these formed where the molten basalt hardened. Of course, these subsequent flows were of different volumes and the rules of stratigraphy cannot be applied. Geologists have worked out these relationships but that is beyond the scope of this report.
Let’s just say that many rivers of magma flowed through this channel, like stormwater through a sewer pipe–some larger than others.
Figure 9. This is an enigmatic photograph because I don’t remember which wall it was on. I didn’t notice the detail when I took the photo, and now I can’t say if this is an excellent example of cross-bedding (always tilts downstream) as in Fig. 7. or a total mystery. My only excuse is that it was TOTALLY BLACK in the cave and I was disoriented the entire time.
Figure 10. We made it out without spraining an ankle or hitting our heads. This cave-in is the only entrance/exit for the downstream part of the tube. There is another one 1.5 miles upstream, but that route is difficult (according to the park information).
Final Thoughts
The Ape Cave lava tube, and the missing forest from my previous post, are part of the Spirit Lake eruption phase of Mount Saint Helens, which began about 1900 years ago and continues to this day. The magma chamber didn’t erupt at the center of the stratovolcano, but instead found an opening along one of the many cracks in the thick pile of volcanic rock that had accumulated during at least 50 million years.
Lava tubes present a unique eruption environment. Ground water that finds its way into the magma chamber cannot escape, thus pressurizing the conduit and altering the lava’s behavior. Imagine lava as thin as water surging through this passage, sloshing around, encountering obstacles, rushing headlong downhill towards what apparently was a small opening, if Fig. 6 is any indication of the narrowing channel.
It was a great drive through a wild terrain to reach Mount Saint Helens, and the destination was worth the effort.
Mount Saint Helens Revisited: A Missing Forest
My last post reported on Miocene (23-5.3 Ma) volcanic rocks on the eastern flank of Mount Saint Helens. Those rocks predate the creation of Mt St Helens, however; we reached our destination and, before exploring a lava tube called Ape Cave, we examined some interesting geology that is part of the most recent eruptive stage of this active stratovolcano. The Spirit Lake stage began about 4500 years ago. There were three earlier stages, beginning about 40,000 years ago; each lasted less than 5000 years.
Figure 1. About 1900 years ago, a large amount of basalt lava flowed from a fissure on the south flank of the volcano (indicated by a square in the inset map of Fig. 2). The lava was hot (~1200 C or 2200 F) and set the forest on fire; when the wood had been turned to charcoal, the lava cooled to leave casts of the trees. My wife is taking a photo of a small-diameter tube we’ll examine it more closely below.
Figure 2. Mount Saint Helens is about 70 miles south of Tacoma (Home in the right map), but the route we followed, around the north and east flanks, takes 3.5 hours to drive. The yellow areas in the inset map are mostly andesite lava flows older than 5 Ma. The circle is where we looked at them in the last post.
Figure 3. These holes were everywhere, forming a hazard for people walking, so a walkway was constructed over the area where the tree holes are densest. They haven’t been cleaned out and most are 3-4 feet deep.
Figure 4. This is the cast of a fallen log. The entrance is shown in Fig. 1; visitors are encouraged to crawl through it, about 40 feet, but it was too tight for us. However, several children I met there had braved the dark, tight tunnel.
Figure 5. This photo was taken a couple-hundred yards from the missing forest. The background reveals the leading edge of a lava flow that’s about ten-feet high. The foreground shows a stream being incised into the landscape, probably created along a collapsed lava tube. Regrowth of the forest is slow in the lava surface; however, there was no mention of whether or not this area was logged in the last century–it probably was, given the documented greed of the forest industry when it came to cutting down trees. However, I didn’t see any large stumps, so maybe it wasn’t worth the effort.
Figure 6. This is a mound of lava projecting up to 8 feet above the surrounding landscape. Several features are worth mentioning: 1) it is circular in plan and about 30 feet in diameter; 2) the upper-center of the image shows concentric bands of ropy lava known as pahoehoe, from its common occurrence in Hawaii; and 3) there is a small cave beneath it where lava ran out of the hardened surface. We’ll see a lot more of that in my next post.
Final Thoughts
Our journey along the backroads took us through a vast terrane of andesitic volcanism created more than five-million years ago. Then, about forty-thousand years ago, a new phase of volcanism began and Mount Saint Helens was created from this rugged ground.
Stratovolcanoes don’t just erupt at their summit, even though that is exactly what Mt St Helens did in 1980; more often they leak lava from the myriad faults and fissures surrounding them, especially in an active subduction zone where the earth’s crust is being compressed, twisted, and warped by tectonic forces.
Life is difficult in such an environment and we are fortunate to have a moment in time frozen for us to contemplate how immense the forces are that constantly reform the surface. Eruptions like the one that destroyed this forest are unlikely to kill many people, but they are crucial in reforming the environment. A new forest grows, possibly inhabited by different species of fauna and flora, and life goes on.
My next post will examine this same eruption event, but at a scale that dwarfs what we saw today.
Mount St. Helens Revisited: Miocene Volcanic Rocks
I couldn’t stay away from this fascinating active volcano. I reported on the recovery of the north flank, after the 1980 eruption, in a previous post. Today I visited the eastern and southern flanks, which were spared the devastation of an enormous explosion.
Figure 1. Mount Saint Helens National Volcanic Monument is about three-hours from Tacoma (Home in the left plate). We took back roads and circumnavigated the volcano today, following NF 25 (seen in the right plate), which took us through a volcanic terrain constructed during the last 23 million years. The circled area is the focus of this post. The rock types vary widely, but they are predominantly andesitic flows, ash layers, and breccias. The usual mixed bag of volcaniclastic rocks we expect in a subduction zone plate margin.
Figure 2. This photo reveals a series of thin beds that suddenly dip towards the road. They are highly fractured to the right of the image. Obviously, these were not recently erupted; they have been deformed in the last twenty-million years.
Figure 3. This image shows layers of volcanic ash that are weathering to reveal how thin the laminae are.
Figure 4. This photo dramatically reveals how much can happen in 10-20 my (million years). It was taken a few hundred yards from the previous photo. To the left are layers of ash that dip away from the camera–juxtaposed with steeply dipping layers that curve to the right and become almost horizontal (in the plane of the image) in the upper-right image quadrant.
Figure 5. This image, taken less than a mile from Fig. 4, reveals thick layers of ash and flows. I didn’t examine them closely, but the middle-right of the photo shows a substantial change in bedding.
Final Thoughts
Mount Saint Helens is part of the Cascades range, an elongate series of volcanoes that have been active for the last 60 my because oceanic crust is being subducted beneath the North American tectonic plate. The rocks we saw today are from an earlier phase of volcanism; they were buried to depths of several miles, deep enough to become cemented, but not deep enough to become ductile. Thus, they failed in brittle fracture as they were compressed by the huge pile of volcaniclastic rocks created along the ocean margin.
What comes up must go down. This simple phrase means that the earth’s upper mantle (including the subducting ocean plate) melted and produced a lot of magma, which rose because of its lower density and high pressure, filling every fracture, expanding them into magma chambers. The mantle collapsed because of these voids and the weight of the recently extruded magma. A balloon being repeatedly inflated and deflated.
Meantime, the compression was inexorable. The recently buried volcanic rocks broke along faults, creating the juxtaposition of volcaniclastic material we see in Fig. 4.
These aren’t geologically old rocks. This is a continuous process that we are able to witness in real time throughout the world.
We’ll see this continuous process in closer detail with my next post.
Review of “Raft” by Stephen Baxter
This is a review that I’m glad to write because, despite my often scathing criticism of what I consider half-finished books, Stephen Baxter finished the job. I don’t particularly like science fiction that borders on fantasy, but he keeps his wildly speculative physics consistent to the end; of course, he has a lot of leeway. The cover photo gives the reader a hint of what’s coming–flying trees?
The story that unwinds checks all the boxes: simple plot with plenty of action; good character arcs that aren’t too extreme; exposition written into dialogue in a very believable way; no extraneous characters or side plots confusing the story; a romantic subplot; a surprising ending, despite the reader knowing what’s coming; and, best of all, he does it in 245 pages.
The writing style is solid and the story is easy to follow. Furthermore, the author doesn’t seem to grow tired of the story after the half-way point, probably because he kept the length reasonable. Science fiction doesn’t have to require 400 pages to be understandable and believable. This reminds me of books written in the 60s and 70s; tell the story with enough background to make it comprehensible, but don’t share all of the notes that went into the final draft.
I recommend this novel to anyone who is willing to see what others can imagine.
Stormwater Project: Planting some grass
We stopped by the PNW garden at Pt. Defiance to see some local plants in the wild, but the gate was locked; so we went to Portland Ave. Nursery to view a wide selection of good base plants for the rain garden. We resisted temptation and only selected a few large grasses for now; I dug some holes and we got them in the ground with a quality planting soil.
I better record the names of the plants as I go or I’ll forget them for sure. The one closest to the camera is Sundowner New Zealand Flax (Phormium ‘Sundowner’); it is an evergreen plant that grows 5 ft. tall, 4-6 ft. wide, and blooms in summer. The two in the middle of the photo are Pampas Grass (Cortaderia ‘Silver Feather’); they grow 5-8 ft. high, 2-3 ft. wide, and bloom in summer to winter. The plant in the background is Cabaret Japanese Silver Grass (Miscanthus sinensis ‘Cabaret’); it will grow 7 ft. high and 4 ft. wide; coppery plumes appear in early fall.
This view shows our new plants, with some potted flowers we found earlier in the summer. They fit in well and should make the back yard look good in the near future.
Wing Luke Museum: A Guided Tour of an Immigrant Hotel
Wing Luke was a pioneering Chinese American lawyer, civil rights advocate, and the first Asian American elected to public office in Washington State. When he died in a small aircraft accident in 1965, the community formed the Wing Luke Museum in his honor. It celebrates Asian-American history and culture, and owns a hotel it purchased to display the lives of early immigrants.
The Yick Fung Corporation was formed by a group of Chinese immigrants because they were legally forbidden from owning property in Washington. This store served as a supplier to restaurants throughout Washington.
South Weller Street led directly to the tidal flats where the church steeple stands today. As part of a downtown reshaping, several hills were flattened and the soil used to fill in the nearshore area.
In addition to supplying regional restaurants, you could buy a third-class ticket to Hong Kong (or maybe Shanghai) for $1500 in today’s money. The store remained open until 2008.
To circumvent some of the financial restrictions, the Chinese immigrants formed associations of people from the same villages back in China. This is the meeting room of one such group. They assisted newcomers and planned civic activities. It was kind of like the YMCA.
This is the game room, where people played mahjong and other games.
The hotel contained about 180 apartments, but some of them had up to three rooms. This was the home of a family with eight children. The hotel remained a center of immigrants until it was closed in 1974 because of updated fire codes (after the deaths of twenty or so inhabitants in about 1972). The Wing Luke Museum purchased it and is renovating it as part of the display.
Every room was required to have a door and window. Most of the rooms were small. That is the light shaft out the window; it didn’t lead anywhere and only extended to the second floor, just for light and air.
Living out of your suitcase?
Here’s the light shaft. During reconstruction the building was modified and reinforced.
The museum also had exhibits displaying artwork and pictorial histories of many Asian immigrants, including Hawaiians. Overall, it was very interesting and worth the price of admission. I think it was $22 for a senior like me.
Fort Steilacoom Park and Lake Waughop
After spending the last five days walking around the back yard, digging the rain garden, I drove my FJ40 to Lakewood to take a look at Fort Steilacoom Park.
This play area was the only fort I saw.
But there were several old barns in various levels of disrepair. Apparently, Fort Steilacoom was the first U.S. military post in Washington, built in 1849 during the dispute with Britain over sovereignty. These barns are remnants of agriculture and the Western State Hospital, a psychiatric facility. The hospital superintendent from 1880 to 1897 was Dr. John Waughop, who turned the site into a botanical garden for non-native plants as part of his rehabilitation program.
The Coast Redwood isn’t native to the Tacoma area, along with many other ornamental species planted by John Waughop.
Lake Waughop was named after the hospital’s most popular superintendent. It is a kettle lake, created from the melting of a huge block of ice after the last ice age while sediment collected around it.
This invasive species is common to Washington. It is bull thistle (Cirsium vulgare). I also saw several thriving thickets of Himalayan Blackberry along the trail. These plants were not part of John Waughop’s ornamental plant garden.
Another ecosystem within the park is the oak savannah. It is the remnant of a native woodland that has been altered for thousands of years by the indigenous people of the PNW. The trees are Garry oak (Quercus garryana), the only native oak species in Washington. This area would have become a conifer forest if not for controlled burning by the local people.
After a three-mile circumnavigation of Fort Steilacoom Park, I finally made it back to my vehicle; unfortunately, there wouldn’t be AC for the ride home on this warm afternoon.
Ready to Plant
I amended the soil with 15 cubic feet (~1/2 cubic yard) of Tacgro compost at about 1:1. That’s the darker soil in the bottom of the pond. The original mulch was spread out 4-6 inches deep, sufficient to cover the grass and weeds; it’s ready for planting.
That’s not my department, unless a hole has to be dug in the stony, original soil.
The total time for this project was about 20 hours. The only cost was 14 bags of compost, less than $100.
Sisyphus and the Stone
I finished the surface today, and dug down about 10 inches to mix in compost for the central planting area. Along the way I encountered this boulder, which weighed a couple hundred pounds. I was able to roll it up the slope, but now what do I do with it? I’ll be using a compost created from yard waste collected by the city of Tacoma to amend the silty soil. The hole ended up deeper than I like, so I’ll need a lot more than four bags…
These are all the stones I could easily remove from the soil I removed and that to be amended by compost. Hauling them in a steel bucket may seem inefficient (it is), but carrying fifty pounds at a time is a lot easier than rolling the wagon up the hill, which is about six-feet higher than the job site. I estimate that I lost 10-15% of the soil volume, which will be replaced by compost.
Timothy R. Keen 
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