Tuesday, August 4, 2015
https://yosemite.peopleadmin.com/postings/1685. The closing date for applications is September 1, 2015.
The sand has several origins. The quartz rich sands have been eroded from distant sources in the Klamath Mountains and Idaho Batholith and carried to the shoreline environment by one of Oregon's many rivers. Other sand is locally derived, eroded directly from the sea cliffs, or carried onshore from offshore bars, sediment that may have originated during the ice ages when sea level was lower. Wave action produced the flat platforms on which the dunes accumulated.
I've only just begun to explore this incredible landscape. I'm usually based out of Florence, so that's where these photos are coming from. Wave action is intense and unending. At times the waves are huge, and onshore winds can approach hurricane velocity. The first ridge of sand, the foredune, absorbs much of the impact of the wind and waves.
The dunes here have been altered extensively in the last century. Urbanization, where it's taken place has been secondary. The big changes resulted from the construction of jetties at the mouth of the Siuslaw and other rivers, which back up the sand along the coast as efficiently as a dam. The other has been the introduction of European beachgrass to augment the stabilization of migrating dunes. The native grasses have been pushed aside in many instances as the European non-native takes over. Because of the spread of grasses, 80 % of the dune sheet is covered by vegetation. In 1939 it was only 20% (US Forest Service data).
The rivers and streams that flow into the dune fields, along with a high groundwater table, have created a network of swamps, and more than two dozen ponds and lakes. Some of the larger lakes have been developed as recreational resorts.The complex provides a rich environment for wildlife, both local and migratory.
One very bizarre species in the area is the Darlingtonia californica, the carnivorous Pitcher Plant. I've written about the small park north of Florence previously. The plants can only grow in nitrogen poor environments like bogs or in serpentine soils. They get their nitrogen from the insects they consume.
Another hazard, one not truly experienced in modern times, is the effect of large tsunamis in the event of a gigantic earthquake along the Cascadia Subduction Zone. Many of the lowland areas are expected to be inundated by tsunami surges that could reach depths of several tens of feet. Evacuation routes are prominently posted in developed areas.
extensive web presence if you want to learn more!
Sunday, August 2, 2015
Vagabonding on Dangerous Ground: "This Dismal Forest Prison" and Other Problems Exploring the Northwest
vagabonding up the Cascadia Subduction Zone last month was how rugged the landscape was. There is a topographic consequence to traveling or living onshore of a convergent boundary. In the long term, the land is pushed upwards into mountains, mountains that in many cases slope directly into the sea. Add to this the orographic effect, which dumps multitudes of rainfall in this northern latitude, and you end up with nearly impassable terrain.
On our trip, we occasionally felt a tiny bit of impatience when the road narrowed and went from four lanes to two. It slowed us on our journey through northern California and southern Oregon. It meant that the coastal route cost us a good thirty or forty minutes over what the trip would have been had we traveled on Interstate 5 farther inland. Thirty or forty minutes! A whole five hours or so to cover the 200 miles from Crescent City to Florence! But it took only a few moments of consideration to realize what an easy time of it that we have getting from one place to another in this landscape, this incredibly rugged and even dangerous landscape.
|Samuel Boardman State Park on the south Oregon Coast|
One of the books we picked up on the journey was called "Two Peoples, One Place " by Raphael and House. It is a history of Humboldt County, and it is a bit unusual in that includes a great deal of information about people other than the Europeans who settled the region in relatively recent times. I haven't read all of it yet, but I was struck by one section, an account of the overland journey that resulted in the discovery of Humboldt Bay in 1850.
It was a miserable journey, by all accounts. The party of eight men took ten days of food supplies for an expedition that lasted around two months. The Gregg Party made their way from the Trinity River to the coast around Patrick's Point, then south through the Humboldt Bay and then up the Eel River. The party split up, with some of them attempting a more coastal route to San Francisco, but ending up in the Sacramento Valley. Gregg himself, their leader, died under somewhat disputed circumstances. The others followed the Eel River, during which they had a tough encounter with eight (8!) grizzly bears. They limped their way south to Sonoma.
The surviving accounts suggest that Gregg was not well-liked by his crew. He was constantly slowing the expedition by taking scientific readings (you know how those scientists are!). Sadly his notes and records were lost (or discarded unceremoniously after his death). How is this for a description of an argument that took place among the crew?
His cup of wrath was now filled to the brim; but he remained silent until the opposite shore was gained, when he opened upon us a perfect battery of the most withering and violent abuse. Several times during the ebullition of the old man's passion he indulged in such insulting language and comparisons, that some of the party, at best not any too amiable in their disposition, came very nearly inflicting upon him summary punishment by consigning him, instruments and all, to this beautiful river.This is, by the way, how the Mad River got its name...
Though they were impressed by the size of the Redwood Trees, they referred to them as a "dismal forest prison". They described the near impossibility of moving their livestock and supplies through the forest floor, as it was covered with multitudes of fallen trees. They were lucky to make two miles a day. In the end they survived mostly by the generosity of the local Native American people who lived in the region. They gave the Eel River its name because of the lampreys they traded for to eat (sounds delicious).
|Arch Rock in Samuel Boardman State Park|
|Samuel Boardman State Park|
But in the present day, it is possible drive the entire coast from Eureka to central Oregon in a long afternoon. And in the absence of the dangers of scurvy, grizzly bears, or starvation, the traveler can sit back and appreciate the incredible beauty of the region. One feels compelled to slow down and enjoy the scenery. Oregon has established a string of state parks along the rugged southern coast of the state, and each one of them is worth a stop.
|Pistol River State Park in southern Oregon|
|Cape Blanco State Park is only about seven miles short of the being the westernmost point of the lower 48 states. Cape Alava in Washington is the far west point.|
Saturday, August 1, 2015
|This is NOT a killer asteroid entering the Earth's atmosphere. It is a sun dog over Oak Flat Campground near Superior, Arizona. Oak Flat is going to become a gigantic crater.|
But the copper wasn't all gone. With prices up, there is renewed interest, and Resolution Mining Company has outlined a huge ore body, one of the largest in the world. But there's a problem.
The normal approach, open-pit mining, won't work. It's far too deep. Normal tunnel mining won't cut it either, because although the ore body is huge, it is low-grade, averaging around 1.5% copper, instead of the 5% or so that is required for profitable tunnel mining. So the company proposes to go after the ore using a process called panel caving (a type of block caving). They propose to start underneath the ore body, design a system of collection tunnels, and then fracture the rock above, allowing it to fall into the collection areas where the ore will be removed.
If the soldiers were U.S. military, I suspect there would be a cacophony of voices raised in righteous anger about the desecration of hallowed ground, and historical heritage and all that. But no, the warriors were Apache. The copper mining company insists that they respect the Native American heritage, and they make all kinds of public relations noise, but a great many local tribes and nations are deeply opposed to the operation.
For an excellent summary of the issues involved, please read this excellent article by Ray Sterns for Phoenix News-Times: http://www.phoenixnewtimes.com/news/a-copper-mine-near-superior-is-set-to-destroy-a-unique-sacred-recreation-area-for-fleeting-benefits-7287269
Friday, July 31, 2015
|Crescent City Harbor from the south|
It's also been described as a tsunami magnet.
Since 1933, tidal gauges in the harbor have detected at least 32 tsunami surges, five of which caused damage, and two that have caused deaths. The 1964 magnitude 9.2 Alaska earthquake caused catastrophic damage in the town, killing eleven people. And ominously, sediments in and near the town record evidence of damage from the 1700 Cascadia earthquake. It is the possible repeat of that event that has the Pacific Northwest in an uproar at the moment.
No other place in California has such a record.
|Photo by Mrs. Geotripper|
|Photo by Mrs. Geotripper|
|Battery Point Lighthouse in Crescent City|
The water withdrew as if someone had pulled the plug. It receded a distance of three-quarters of a mile from the shore. We were looking down, as though from a high mountain, into a black abyss. It was a mystical labyrinth of caves, canyons, basins, and pits, undreamed of in the wildest of fantasies.
The basin was sucked dry…In the distance, a black wall of water was rapidly building up, evidenced by a flash of white as the edge of the boiling and seething seawater reflected the moonlight.
Then the mammoth wall of water came barreling towards us. It was a terrifying mass, stretching up from the ocean floor and looking much higher than the island. Roxey shouted, “Let’s head for the tower!” - but it was too late. “Look out!” he yelled, and we both ducked as the water struck, split and swirled over both sides of the island. It struck with such force and speed that we felt we were being carried along with the ocean. It took several minutes before we realized that the island hadn’t moved.
When the tsunami assaulted the shore, it was like a violent explosion. A thunderous roar mingled with all the confusion. Everywhere we looked buildings, cars, lumber, and boats shifted around like crazy. The whole beachfront moved, changing before our very eyes. By this time, the fire had spread to the Texaco bulk tanks. They started exploding one after another, lighting up the sky. It was spectacular!
|Tsunami damage in Crescent City from the 1964 Alaska Earthquake|
Vagabonding on Dangerous Ground journey north on Highway 101. We were about to enter Oregon, and a beautiful stretch of coastline (as if it hadn't already been beautiful).
Wednesday, July 29, 2015
|A very strange-looking sandbar at Big Lagoon in Humboldt Lagoons State Park on California's north coast.|
But when that geologist walks ONTO a bar, she just gets sand on her feet.
Yeah, yeah, I know, shut up and stick with the science...
We're traveling north on a journey through the Cascadia Subduction Zone, exploring this unique region with an eye to the geology, and the beauty, of the region. We've explored the Redwood forests of the Eel River, and the Lost Coast where the Cascadia zone begins. Today we are looking at a unique state park along the coast north of Eureka, California, and south of Crescent City. It's called the Humboldt Lagoons State Park, and the three lagoons found there are bounded by stunning examples of baymouth bars.
|Big Lagoon at Humboldt Lagoons State Park (source: Google Earth)|
|Big Lagoon at Humboldt Lagoons State Park|
Intense rainfall sends sediments down the many rivers and streams, and vast amounts are added to the coastal waters. When waves encounter the coast at an angle, the swash and backwash of the water causes sediment to be transported along the coast, a process called longshore drift. There is a tremendous amount of sediment in this coastal system.
|Humboldt Lagoon also include a county park at the south end of Big Lagoon. It's a nice place to see coastal erosion!|
In most bays along the Cascadia coast, rivers are large enough to keep the bays open, but at Humboldt Lagoons only small streams are present. Water can simply seep through the sandbar rather than flowing out. The bays are breached only during the wettest, most intense storms. The baymouth bars are miles long, and incredibly straight (see the Google Earth image above). They don't look natural, and yet they are.
|Smaller Stone Lagoon is just north of Big Lagoon.|
The next stop on our vagabonding tour of the Cascadia Subduction Zone is Crescent City at the far north end of California. We'll have some things to learn about tsunamis in California.