Friday, April 30, 2010

My First Day of "Summer"...

Well, this is what a "compressed academic schedule" looks first day of summer employment hiatus. A few years back the school wanted to run three full semesters a year, so shortened our fall and spring semesters to 15 weeks, adding a few minutes to every class and laboratory section. Some people like it, but it has had an unfortunate impact in the sciences, as we went from 17 labs to only 15. You can't spread the content of the two missing labs very well among the others. Unfortunately the summer semester was decimated by the California budget crisis, so I am presently idle, as my summer classes were canceled.

Well, I don't want to vegetate, so I am off to the eastern side of the Sierra Nevada for a conference of the National Association of Geoscience Teachers. To get there, we had to drive over Carson Pass on Highway 88 through Kirkwood Ski Resort, to Genoa, Nevada, then to Lee Vining and Bishop, a little over 300 miles. It's April 30, and it was snowing in the mountains yesterday! Luckily, the roads were dry and clear today.
The snow pack is obviously still pretty thick, so the geology is a bit obscure, but along the way to Carson Pass we passed Caples Reservoir, where we could see the high peaks composed of andesite lahar deposits from around 10-20 million years ago. They have been extensively modified by the Pleistocene glaciers, and make a beautiful backdrop to the lake.

We made our way south to Conway Summit, where we had a startling view of Mono Lake and Mono Craters. Mono Lake is the very salty remnant of an ice age lake that was hundreds of feet deeper, and once spilled over into the Owens Valley. The only way the water leaves to day is by evaporation. The story of the near destruction of the lake ecosystem because of the diversion of water by Los Angeles could fill many blog posts (and probably will before too long).
The Mono Craters are actually rhyolite plug domes that have erupted between about 35,000 years to only 600 years ago (the youngest, Panum Crater, is the small one in the foreground). They may be part of an evolving caldera, but mass destruction is probably hundreds of thousands years away.

In the late afternoon, we crossed through the Long Valley Caldera, which did cause massive destruction across the entire region 760,000 years ago. An eruption explosively tossed 130 cubic miles of ash across most of the western United States, and the ground over the magma chamber collapsed to form a hole that is 10 miles by 18 miles, and once may have been two miles deep. The high peaks of the Sierra Crest that form the western and southern edge of the caldera are composed of Paleozoic and Mesozoic metasedimentary and metavolcanic rocks that have been intruded by Cretaceous granitic rocks.

Tomorrow we will be geotouring through region, and more pictures will undoubtedly follow! Mrs. Geotripper took the top and bottom photos, I took the others.

Thursday, April 29, 2010

One of the Biggest Political Ironies I think I will ever see...

1969 Oil Spill in Santa Barbara Channel, California (AP photo from Los Angeles Times)

However one might feel about drilling for oil in the continental shelf of the United States, the events of the last month have to stand as one of the greatest political ironies in the country's history. One month after a Democratic (!) president opens up vast areas for offshore drilling, a massive explosion kills eleven people on an oil rig in the Gulf of Mexico, and a huge oil slick is making landfall along the shorelines of what will ultimately include four states. You may be able to think of some better examples, but it makes me think of the signing of the Treaty of Guadalupe Hidalgo which ceded California to the United States on February 2, 1848, when unbeknownst to the signing parties, gold had been discovered in California on January 24 of the same year. We are only seeing the beginning of what will be a long and painful time for the coastal cities, not to mention the ecosystems found there. The political ramifications will last far longer; the oil spill in the Santa Barbara Channel in 1969 still resonates today. And so does the 1989 Exxon Valdez disaster.

I hope that the damage can be contained. It won't do anyone any good if the beaches all along the southern coasts are coated with muck. I do hope it will start a national conversation about our priorities. Despite the shrill cries of "Drill Baby, Drill", pulling the oil out of environmentally sensitive areas will do next to nothing to achieve energy independence. Without imported oil, we would pretty much use up our entire inventory of US petroleum reserves in maybe five or six years. Where will we be, then? We need to plan for a post-petroleum economy before it is forced on us, not after. It is the only way to avoid an economic disruption that will make the present-day recession look like the Roaring Twenties. But how can you explain that to representatives and senators who are incapable of looking beyond their next election day?

Deep Sea News provides a very good timeline of the events in the Gulf of Mexico.

I don't want to make light of a horrible situation, but I hope no prominent politician stands up to say how absolutely safe nuclear power is now...

A perfectly frivolous (and delicious) post...

I know it's not the first time that a layer cake has been used as an analogy for stratigraphy, but what about tectonic-stratigraphic relationships? I couldn't help but notice that the cake that showed up at our last historical geology class had some extra geological complications: I'm pretty sure we have an ocean-continent convergent boundary, complete with a magmatic arc on the right, a yellow forearc basin in the middle (representing our own local geological environment), and an accretionary wedge made up with a melange of candy sprinkles. The chaotic nature of the accretionary wedge became more apparent when we had to carve and serve the cake with little plastic spoons!

If you want to argue about the exact placement or angles of the various elements I'm describing, I challenge you to cook up and post something better! Thanks to Melissa for the cake, and Erricka for the picture!

Tuesday, April 27, 2010

Guess What Else the Devils Hole Pupfish have had to put up with over the last 20,000 years?

I wrote about the precarious existence of the Devils Hole Pupfish a few months ago. The highly endangered fish live in a single cavern opening in the Death Valley region in water that is at a constant 92 degrees or so. They've had to put up with a lot over the years: declining lakes and rivers as the ice ages ended, predation, blazing hot temperatures, isolation and inbreeding, and human disturbances, garbage, groundwater pumping, and intrusive biologists measuring every aspect of their existence. Cameras monitor their every move. So what else?

The USGS camera monitors at Devils Hole caught the effects of the shaking of the Easter Sunday 7.2 magnitude El Mayor-Cucapah earthquake. Although Devils Hole is situated hundreds of miles away from the quake epicenter in Baja California, the water was disturbed by the waves passing through the region. And from looking at the video, 'disturbed' is a gentle term; the water was sloshing rather violently. The fish look a little confused, but were apparently not adversely affected, although sediment was redistributed about the small ledge where they derive most of their food. Not that any single fish would remember it, but the small pond has probably been shaken hundreds of times in the last 20,000 years that they have been isolated here, and they still survive.

Read the USGS analysis here. If the link to the video above doesn't work, try here. Thanks to Lee Allison of Arizona Geology, and Dave Schumaker at Geology News for the catch.

New Blog on Yosemite: Yosemite Nature Notes

Check out a new blog on the natural history of Yosemite National Park: Yosemite Nature Notes by Pete Devine. I don't know if you have figured this out, but Yosemite is one of my favorite corners of the world, and I'm always interested in new points of view and up to date information about the park (The Yosemite Blog has been doing a great job for years). Check it out, and give Pete some encouragement!

Monday, April 26, 2010

The Revival of Professor Incognito!

It's the end of a long semester, and finals week looms! I've been swimming through a massive pile of laboratory manuals and quizzes for the last four days, and for a few glorious hours I am caught up with the grading. It seems an appropriate time to revive a character who appeared on this blog last year about this time. Professor Incognito is the creation of Zeo at, a comic artist whom I admire greatly. Although I am related to the artist, she refuses to reveal the inspiration for her professor character. I certainly know it couldn't be me. I mean, I would NEVER say things like this...well...almost never.

Anyway, I must say that thus far my students have exhibited a great deal of restraint in terms of begging for a passing grade. They mostly seem to know where they stand. But with finals coming up, I figure it can't hurt to clue them in as to what might happen if they try to con a grade they don't deserve. After all, they are ALL reading this blog, because I told them at the beginning of the semester that it would be fun and interesting to read. And who ever ignores advice from a professor? Especially my fine students, and in all seriousness, I have some stellar students this year. It has been such a pleasure working with them

Oh, and for those thinking about a geology class in the fall? I welcome you! I welcome you all! Up to the limits being imposed on us all by the rationing of education by the state of California. If you make it into a class, by golly make it count! Don't be the other incognito character below...

Sunday, April 25, 2010

Frazil? What the heck is Frazil? Strange Ice at Yosemite National Park

A giant slurpee! Check out this interesting mini-documentary from the National Park Service and the Yosemite Fund (via Frazil ice accumulates around the base of Yosemite Falls in the spring and does strange things. In some of the scenes, the ice flows alike a'a lava, complete with flow levees and breakouts. The footage of ice falling off the cliffs is pretty spectacular as well. It is fun to listen to when wandering about the area.

New Accretionary Wedge is Up!

The latest edition of the Accretionary Wedge is up, here or here! Callan Bentley at Mountain Beltway did a great job of hosting. The topic was geological heroes, the people who inspired we geologists along our career and life paths.

Scarps to the Left of Me, Sag Ponds to the Right, Here I am, Stuck in the Middle with You!

The San Andreas fault is the best known (and most feared) fault line in California, and yet few people know where it actually is, and might not even know it if they were living on it (and far too many people in the state do live on the fault line, not only the San Andreas, but many others as well). The San Andreas is remarkably accessible, and there are only a few places where the fault lies more than a mile or so from a paved highway. One very accessible site to see the fault can be found at Tejon Pass on the main freeway connection between northern and southern California. Interstate 5 crosses the fault at Gorman, but a stop on the freeway would be very dangerous. If you exit at Gorman and follow the frontage road east (Gorman Post Road), you can see some wonderfully exposed fault features from a safe vantage point. Unless the BIG ONE hits. Then again, I'd rather be out in the open watching a scarp forming than being trapped in a building somewhere.

The most obvious fault feature is the linear valley. In the picture above, the fault follows the shallow valley in the foreground to the notches on the horizon to the left. I was standing atop a scarp (a fault-formed terrace) that resulted from large earthquakes every few centuries (the last major quake here occurred in 1857, with a magnitude of about 7.8). The juniper bush is growing on the slope of the scarp.
A little to the west of the first photo, the fault is marked by a linear pattern of springs and vegetation. The brush-covered hill just right of center is another fault scarp.

The motion of the San Andreas is right-lateral, meaning that objects on the side of the fault opposite the observer are shifted to the right. As mentioned in a recent post, the Neenach Volcanics which show up just east of here have been separated by 195 miles over the last 10 million years or so. The other half of the Neenach volcano is exposed at Pinnacles National Monument near Hollister in the Coast Ranges.

The lateral motion of the fault produces disruptions and offsets of streambeds, and lakes often result. The picture above is a sag pond on Gorman Post Road. If you think about it at all, natural lakes are a rarity in southern California. Many lakes result from Ice Age glacial scouring, which wasn't much of an issue this far south. Others, like Crystal Lake in the Angeles National Forest, result from landslides that block creeks. But a rather large number of lakes can be found along the trace of the San Andreas and other active faults, such as the one above. It's a great bird-watching spot too!

This is a serious geology blog, so you know that I wouldn't put together a geology blurb just so I could show pictures of the glorious wildflowers I saw last weekend...but I am in fact showing you some flower pictures. The slopes in the picture above were just west of the sag pond. They were gorgeous! Just the same, the Gorman stop is a great place to see some fault features at the cost of just a few minutes of your time while traveling on Interstate 5 any time of the year. And you know you needed a bathroom stop anyway....

Below is another gratuitous flower picture. The color explosion includes California Poppies, Lupine, and a blue flower I am not familiar with. An identification would be welcome!

Saturday, April 24, 2010

The Other California: Caught in the Vise (the Western Mojave Desert)

The western Mojave Desert is a little-known corner of California, except during the late winter and spring when parts of the desert come alive with Golden Poppies, Lupine, Goldfield, Cream Cup, and Desert Larkspur. Now, my readers know that I would NEVER stoop to thinking up some geology to talk about just so I could show some pictures of flowers from my trip through the area last week. So feel free to ignore any flowers that just happen to impose themselves between you and the very important mountains that make up the horizon of the pictures below.

The western Mojave is the relatively flat triangular region lying between the Garlock and San Andreas faults (see the NASA image above). The Garlock is a fault that few Californians hear about. It has not produced a major earthquake in perhaps a thousand years, with the largest historical quake being a 5.7 magnitude event in 1992. It is thought capable of producing much larger tremors, as high as magnitude 7.6 . The Garlock is a left lateral fault (the side opposite the observer moves to the left) that has shifted as much 40 miles.
In the picture above, the Garlock fault lies at the base of the Tehachapi and El Paso Mountains in the far distance. The Tehachapis are composed of granite and metamorphic rocks, and make up the southern "toe" of the Sierra Nevada. 4,000 foot high Tehachapi Pass (below) is a major transportation corridor between northern and southern California, including the last railroad crossing over the Sierra Nevada for some 300 miles (the next crossing north is at Donner Pass near Lake Tahoe).
The more familiar San Andreas fault is the 600 mile long transform boundary that divides the North American plate from the Pacific Plate. It was been responsible for two of California's biggest earthquakes: the 1857 Fort Tejon quake and the 1906 San Francisco tragedy. The area southwest of the fault is moving northward about 2 inches a year, breaking loose in large earthquakes every two or three centuries. In the picture below, the San Andreas lies just over the ridge in the distance.

I wrote about the Antelope Valley California Poppy Reserve in a previous post, so I won't add much here other than to say that the low hills of the preserve provide a wonderful view of the landscape produced when two major fault systems converge on each other...especially in spring.

The Other California is my continuing series about the less familiar parts of the state that don't usually show up on the postcards. I am cheating just a little because poppies show up on almost ALL the postcards. And yes, the picture below is just simply a gratuitous flower picture...

Thursday, April 22, 2010

Accretionary Wedge #24: Our Geological Heroes

Callan Bentley at Mountain Beltway is hosting this month's Accretionary Wedge, with the goal of paying tribute to the extraordinary individuals who helped make our life, our science, and our planet better than they would otherwise have been: our geological heroes.

It took me awhile to consider who that hero would be, because I have had quite a few in my life...I've written about some of them, especially here and here. But given the coincidence of the Wedge and fortieth anniversary of Earth Day, I thought I would talk about one of the more important literary influences that led me to where I am today: a teacher, a geologist, and an unapologetic environmentalist: an advocate for the Earth, not because I love it more than the people that live on it, but because a healthy planetary ecosystem is a better place for people to live.

With that in mind, I offer up my geological hero: Edward Abbey. Anyone my age in the outdoor sciences probably traces their love of the outdoors to his rants in books like Desert Solitaire and the Monkey Wrench Gang, and it might seem odd to consider his screeds to be a celebration of humanity. In fact, one feels he would have preferred a world without humans (from the last chapter of Desert Solitaire):

"In deep stillness, in a somber solemn light, these beings stand, these fins of sandstone hollowed out by time, the juniper trees so shaggy, tough and beautiful, the dead or dying pinyon pines, the little shrubs of rabbitbrush and blackbrush, the dried-up stalks of asters and sunflowers gone to seed, the black-rooted silver-blue sage. How difficult to imagine this place without a human presence; how necessary. I am almost prepared to believe that this sweet virginal primitive land will be grateful for my departure and the absence of the tourists, will breathe metaphorically a collective sigh of relief - like a whisper of wind - when we are all and finally gone and the place and its creations can return to their ancient procedures unobserved and undisturbed by the busy, anxious, brooding consciousness of man.

Grateful for our departure? One more expression of human vanity. The finest quality of this stone, these plants and animals, this desert landscape is the indifference manifest to our presence, our absence, our coming, our staying or our going. Whether we live or die is a matter of absolutely no concern whatsoever to the desert. Let men in their madness blast every city on earth into black rubble and envelope the entire planet in a cloud of lethal gas - the canyons and hills, the springs and rocks will still be here, the sunlight will filter through, water will form and warmth shall be upon the land and after sufficient time, no matter how long, somewhere, living things well emerge and join and stand once again, this time perhaps to take a different and better course. I have seen the place called Trinity, in New Mexico, where our wise men exploded the first atomic bomb and the heat of the blast fused sand into a greenish glass - already the grass has returned, and the cactus and the mesquite. On this bedrock of animal faith I take my stand, close by the old road that leads eventually out of the valley of paradox.

Yes. Feet on earth. Knock on wood. Touch stone. Good luck to all."

A world without people? Maybe. But Abbey wrote his books to all of us, in hopes that his readers would come to understand the Earth in a different way. I grew up in the sixties, when the very idea of limiting our emissions from cars and factories was a laughing matter. Plumes of filth rising from smoke stacks was a sign of financial security. Dumping waste in our rivers was a convenient way to make bad things disappear. Paving over wildlands was a sign of success, of human domination over the land. Earth Day was first seen by many as another amusing hippie protest, all wrapped up in other protests over wars in faraway places.

In 1967, the first picture of the entire Earth was taken from space. In 1968, Edward Abbey published Desert Solitaire. In 1970, the first Earth Day took place. I don't know that Abbey's book was as influential as the other two events, but when I picked up the book for myself in the early 1970's, it provided me a new way to look at the planet, and was one of several events that led me on the path into geology, and even more importantly, into teaching.

We as a people made progress towards a cleaner and safer world in the 1970's, with the Clean Air Act, the Clean Water Act, the Endangered Species Act, and the EPA (plus the Wilderness Act of 1964). There was a backlash in the 1980's, as the military-industrial complex caught on to the PR game. We lost many critical years in our fight for a sustainable clean energy future after 2000, but we may find ourselves forced to confront the issue as oil runs short. We appear to have confronted the problem of ozone depletion successfully.

But there are still so many problems. Today, humanity faces a craven political stalling game over global warming by those who stand to lose profits in the energy industry. That global warming is happening is not in doubt. That we have caused it is also not in doubt. Finding solutions will be difficult, especially in the face of a well-funded manufactured doubt "controversy". We face an appalling problem of soil erosion and loss. The agricultural soil base of our food supply was greatest some 10,000 years ago, and we have been losing it ever since. The vast increase in production of the last century has come from an intense application of energy and chemicals that will soon be in short supply.

The Earth is an impassive mother. She doesn't exactly care if we survive or not, and 99% of all the species that ever emerged on our planet are extinct, for many different reasons. We humans are apparently the first species ever to be aware of that fact. What choices will we make with that knowledge?

Today's picture is moonset under Landscape Arch, the largest span (290 feet) in Arches National Park, and the either the largest or second largest in the world.

Tuesday, April 20, 2010

Life from an Ant's Point of View...

I was going to find some kind of geological note to add here, but I did that pretty extensively yesterday, so today, it is just a bit of whimsy...have you ever wondered what springtime on the Antelope Valley California Poppy Reserve looks like from the point of view of an ant??

Monday, April 19, 2010

The Other California: Mammoths and Sabertooths rise from the Prairies again!

Painting for the San Joaquin Valley Paleontology Foundation by David Douglas

Sometime back, I talked about the rich paleontological discoveries being made at the Madera County Landfill at Fairmead near the center of California's Great Valley. I mentioned the efforts to build a visitor facility, the Fossil Discovery Center, but also mentioned that I had not had the opportunity to visit the site yet. That changed today, and I am happy to report that the facility is rapidly becoming a reality. It is expected to be open for business in June.
The Fossil Discovery Center is on the corner of Road 21 1/2 and Road 19 a short distance from Highway 99, near the town of Fairmead. As can be seen, the exterior of the building is essentially complete, and when I stopped by, workers were busy putting in the high-tech connections, and working on the interior labs and classroom. I was pleased to have the opportunity to talk to Grady Billington, the President of the Board of the Directors of the San Joaquin Valley Paleontology Foundation. He kindly provided me a tour of the facility and discussed their plans for introducing valley residents to the fascinating prehistory of the region.
A full-sized mammoth skull has been hung in the central atrium. More than three dozen species of animals have been discovered at the landfill, including mammoths, mastodons, sloths, camels, horses, dire wolves, smilodon sabertooths, and short-faced bears. Skeletons of most of these animals will be part of the display when it is complete.

The original environment where the animals lived and died was a prairie with ponds and rivers flowing out of the adjacent Sierra Nevada. An outdoor pond has been constructed to recreate some of the conditions present when the Pleistocene animals were roaming the area. The hill in the background of the photo is the landfill site where the fossils were uncovered.

For more information, check out the website for the San Joaquin Valley Paleontology Foundation, or look for almost daily updates on the Fossil Discovery Center of Madera County site on Facebook.

For those who are new to Geotripper, the "Other California" is my long-running web series on the fascinating geological places in my fine state that don't usually show up on the postcards. Thanks for reading!

Sunday, April 18, 2010

The Other California: A Wandering Volcano and a Floral Outburst

I can still be astounded....

There are lots of things I haven't seen and done in my life, but I can imagine what it is going to be like to see a rhyolitic volcano erupting at close quarters, or to feel a magnitude 8 quake (6.9 is my biggest so far). But sometimes things happen that just leave me breathless, if only from the unexpectedness of it all. That's what happened to me today.

I had always heard about the Antelope Valley California Poppy State Reserve, but had never seen it, especially in the late winter or early spring when the blooms are at their peak. We were taking an alternate route home, generally following the San Andreas fault from Cajon Pass to Grapevine Summit on Interstate 5. The desert was mostly dry and barren for much of the route, but as we passed Palmdale and Lancaster, I looked west and saw something I had never seen before: orange hills. Fluorescent orange hills. As we drew closer, it was clear that the California Poppies were at their golden best.

After expending several hours using vast amounts of digital space on my camera, I started to ponder why the flowers were here, and not elsewhere across the Mojave Desert, at least not in such dominating numbers. I first considered the slightly higher elevation, the local rocks and sediment, soil conditions and drainage, but I started to realize there was another dynamic going on...the flowers are a natural phenomena, but a natural phenomena with a very human influence. About seven miles west of the Poppy preserve there is another state park: Arthur B. Ripley Desert Woodland State Park. The park preserves 580 acres of what turns out to be the native land cover of the Mojave Desert west of Lancaster and Palmdale: juniper woodland and Joshua Trees.

A century ago, this high end of the desert was cleared of Joshua Trees and Juniper, usually by chaining (dragging a huge chain between tractors that knocked down whole forests) or fires in order to put in thousands of acres of alfalfa fields and other crops. Large areas were reserved for sheep and cattle grazing as well. The natural plant cover was long gone. Much later, some of the abandoned fields started to recover, and the showy wildflowers represent some of the pioneer species (I've noticed for years that the best wildflower shows in any forested areas occur after fires: Yellowstone, Yosemite, and many other areas). Without any nearby natural vegetation, there is no way for the native Joshua Trees and other large trees and shrubs to recolonize the valley floor; they don't have any method to spread their seeds widely (Joshua Trees were once spread in giant ground sloth poop...). Despite their incredible beauty, the wildflower displays are a monument to our extensive alteration of the environment that once existed here.

Just the same, the flowers were one of the most intense displays of color I've ever seen. Lest you think that I had discovered some isolated and unknown Eden, well, a look at the photo below should dissuade you from thinking that these poppies are a well-kept secret. It was actually impossible to get to the park visitor center due to the traffic. Just the same, there was plenty of parking both east and west of the park, and the poppies and other flowers were every bit as abundant. We had no trouble finding some wonderfully quiet corners to contemplate the beauty.

As to the wandering volcano of the title? Just west of the preserve, some unusual rock outcrops can be seen near the junction of Lancaster road and Highway 138 at Neenach. These rocks, the Neenach Volcanics, are about 23.5 million years old, and lie adjacent to the San Andreas fault. The volcano is only half here; the remainder sits on the other side of the fault, 195 miles to the northwest, at Pinnacles National Monument, which I have discussed earlier, here and here. For several reasons, the Neenach Volcanics have not been exposed in the spectacular manner of the rocks at Pinnacles, but the story they tell is just as compelling.

So there, I found a geologic connection that allowed me to show you some flower pictures. You'll probably see a few more gratuitous flower pictures in coming posts. I took around a hundred, and I have to show them to somebody...

For those who are new to Geotripper, the "Other California" is my long-running web series on the fascinating geological places in my fine state that don't usually show up on the postcards (although I've been known to break my own rules every so often; California's poppies are on postcards all the time).

Thursday, April 15, 2010

10 Great Places to See Geology in Action!

Larry Bleiberg from USA Today asked my help in designing a list of 10 great places to see geology in action and I was quite thrilled to participate. The article appears in the travel section of this weekend's edition. I had to think pretty fast, and we came up with the list that appears below.
Grand Canyon (above)
Death Valley (below)

Hawaii Volcanoes National Park

Yellowstone National Park

Dry Tortugas National Park, Florida, and Mammoth Cave, Kentucky

(for the coral reefs, past and present; but I don't have pictures)

Mount St. Helens National Volcanic Monument

San Andreas Fault, California (Carrizo Plains and Point Reyes)

Jasper National Park, Alberta, Canada

Great Smoky Mountains National Park (no picture for this one either...)

I'm wondering what places you would have mentioned...

8.4 Quake in California? Not so fast there, Twitterers...

If you have not read XKCD comics, you have been missing out on a great treat, especially if you are the scientific nerdy type of personality. On the heels of the Sierra El Mayor earthquake in Baja California, the comic above made the rounds, revealing a great truth: we are a wired, interconnected society (surprise!). Of course, there are the disadvantages as well.

So, to explain Tuesday's brief post: the XKCD comic above came true in a fashion...except there was no earthquake. I was checking my e-mails during a short break in my night class, and I had several people asking if the tweets they had received from friends were true, was the state of California declaring that an 8.4 magnitude quake would be hitting within the next 48 hours? Then I saw a few phones open up in class, and someone asked me directly about the Tweet on their phone. Clearly a rumor was spreading with the speed of electromagnetic energy and texting fingers. A hoax? An idiot crying 'fire' in a theatre? Undoubtedly. I posted my brief message explaining why the Tweet wasn't true, and had more than 2,000 hits in the space of 90 minutes. By the midnight, the 20th ranking query on Google was '8.4 magnitude earthquake in California'.

A lot of damage is done when rumors like this spread. No one can predict earthquakes, and a false prediction like this (or from 'psychics') can unnecessarily frighten people, and lead to a situation that will be perceived as crying 'Wolf'. People will stop paying attention to real warnings by qualified seismologists and vulcanologists.

We cannot predict earthquakes in such a way as to know the day, the week, or the month. We can use the history and prehistoric behaviour of fault zones to determine the possibility of a large quake within a time frame of decades. If you want a scientifically grounded prediction about earthquakes in California, check out the diagram below, from the Uniform California Earthquake Rupture Forecast (UCERF). The message to take away? Ignore the tweets, and pay attention to your personal emergency preparations. Quakes will happen.

Tuesday, April 13, 2010

8.4 Quake in California? Don't believe everything that Tweets...


I should stop there, but I will say that no one can predict quakes in any useful way.

California's biggest quakes will be in the range of 7.8-8.0, quite a few times smaller than an 8.4. The stresses are there for a large quake to happen, but a magnitude 8 quake is given only a 4% chance of occurring sometime in the next 30 years.

Please don't believe everything that tweets....

But do prepare for quakes in California. They CAN happen any time, but NO ONE can predict them.

Monday, April 12, 2010

A Change of Subject, and a Request for Help

I have a big change of subject, and I am hoping you will help out. I've got wonderful news that my cousin has found a donor match that may put an end to her battle with leukemia! But the thing is...the donor is NOT a relative, it is a stranger, out there somewhere, a person who volunteered something of themselves. I was slow about joining the National Marrow Donor Program, but I am in now, and I am asking you to become a potential donor too. It's free, it's not hard, and if you are a match, the procedures are not as invasive as you might think. You can save someone's life, someone who is struggling right now, someone with a husband, a wife, children, grandchildren, someone who could have a chance of life because of you. Please consider it!

Sunday, April 11, 2010

The Other California: Taking Stock of the Castle Crags

Driving on Interstate 5 north of Redding is a sometimes terrifying affair. The highway follows the Sacramento River in a winding canyon with plenty of twists and turns. The terror isn't necessarily the road itself as much as it is the giant trucks and recreational vehicles which are being driven as if they were still on a straight freeway in the Central Valley. They don't exactly stick to their lanes. The other hazard comes from following geologists on their way north to see Mt. Shasta: at a particular loop on the highway near Dunsmuir, they are very likely to slam on the brakes as the Castle Crags come into view...

This is part of my continuing series on the "Other California", an exploration of those wonderful parts of our state that don't always show up on the postcards. Today we are wrapping up a journey through the Klamath Mountains. It has not been an exhaustive survey as it is one of the corners of the state that I have yet to fully explore. I want to reiterate my invitation: be a geotripper geoblogger! Have you been to Shasta Caverns? Backpacking in the Trinity Alps? Explored any gold mines near Weaverville or Shasta City? Write a short narrative, or if you don't trust your writing skills, just send some nice pictures, and I will find something to say.

The Castle Crags are certainly a shock when first seen from Interstate 5. The light-colored cliffs rise 3,000-4,000 feet above the river canyon, and stand in stark contrast to the lower heavily forested ridges that make up most of the surrounding area. The peaks and domes remind some people of the Sierra Nevada, and the comparison is apt; the Crags are composed of granitic rock, and as noted previously, the Klamaths are a northern extension of the Sierra Nevada. Their geologic history is similar, with one big difference: the Sierra range is composed mainly of granite intrusions (plutons), but in the Klamath Mountains, the intrusions are smaller and isolated from each other.

A batholith is a single intrusion exposed over an area of 100 square kilometers (40 square miles), although the term can also refer to a vast agglomeration of many dozens of adjacent plutons, as is the case in the Sierra Nevada. There are several of these composite batholiths in the western United States, including the Sierra Nevada, the Idaho, and the Southern California batholiths. The Castle Crags and other small isolated plutons are referred to as stocks. The limited areal extent of the Castle Crags pluton is apparent in the photo below. The surrounding rocks are the more easily eroded metamorphic rocks of the Eastern Klamath Terrane (the Trinity Complex).

The rocks of the Castle Crags formed about 163 million years ago when the Pacific Plate sank beneath the edge of the North American continent in an extensive subduction zone (the same kind of subduction that produces the Cascades volcanoes in the present day). Water released from the descending plate acted like a catalyst leading to the melting of rock deep in earth's interior, and the resulting magma bodies rose until they lay just a few miles beneath the surface. The rock cooled slowly, over tens of thousands of years, forming granodiorite (a coarse-grained granitic rock with significant amounts of plagioclase feldspar). At times, magma reached the surface producing volcanic eruptions, but the volcanoes at Castle Crags have long been worn away. In other words, standing on the granitic rock of the peaks here, one is actually perched under a long-gone volcano.

The sharp spires and rounded domes of the Crags are the result of having a great weight removed. Having formed at depths of three miles or more, the rocks expanded as erosion removed the heavy overlying rocks. But rocks can't expand like marshmallows; they fracture, much like the crust of baking loaves of bread. Vertical cracks are joints. Closely spaced joints promote the formation of the spires and towers of granitic rock. Fractures parallel to the surface are called exfoliation sheets. Exfoliation tends to remove to remove corners and edges, resulting in the formation of domes (Half Dome in Yosemite is a half-good example).

The Castle Crags were also glaciated, but with top elevations of less than 7,000 feet, the glaciers were small, and had less to do with the overall shape of the mountains than jointing and exfoliation. A few small lakes and moraines are found on the north side of the peaks.

Castle Crags State Park honors the Castle Crags, but does not actually encompass them. The park boundaries include the heavily forested southern and eastern flanks of the crags, and part of the Sacramento River, but the granitic cliffs and domes are protected as the Castle Crags Wilderness Area, administered by Shasta-Trinity National Forest. The state park offers a nice campground, with several trailheads that provide access to parts of the wilderness, as well as 8 miles of the Pacific Crest Trail. A park road leads to a spectacular viewpoint that takes in the Crags and nearby Mt. Shasta.

Vennum, Walter, 1980, Petrology of the Castle Crags pluton, Klamath Mountains, California: Summary, GSA Bulletin; v. 91; no. 5; p. 255-258.

Vennum, Walter, 1994, Castle Crags, California Geology, March/April, pages 31-38.

Friday, April 9, 2010

The Other California: Back on the Prairielands

I started my Other California series last year with a post on the little-known and under-appreciated prairielands of the state, a vast landscape surrounding the Central Valley (and which once was the Central Valley in the days before agricultural development). When I conceived of the idea for the prairielands posts, I was in the Sierra Nevada foothills in late fall when all was dry and barren. I revisited the original site today to witness a different world, one that was green and full of life.

The soils in our part of the Sierra foothills are underlain by andesitic mudflow (lahar) deposits that poured off the higher mountains around 9-10 million years ago. The hills in the distance (and around the lake below) are metamorphic rocks of the Foothills Terrane, dating from around 200 million years ago.
We had a reasonably decent rain season, with close to 100% of average precipitation. We really needed about 120% to overcome the three years of drought, since many of the soils around the state are exceedingly dry and need to be replenished, but on this day there was plenty of water in evidence in the normally dry creekbeds and stockponds. One of our favorite stops is a little lake on Willms Road in the vicinity of Knights Ferry on the Stanislaus River. Vast numbers of birds are usually in evidence.

Since getting my first digital camera 9 years ago, I have concentrated on geological subjects, but I have been adding more plants and animals to my repertoire. There is an old adage about geological field work, that you will spend an entire field season collecting every unusual and unique rock in sight, and later come to the realization that you never collected a single specimen of the most common rock in your study area. My bird pictures are kind of like that. I have few pictures of the most common birds in our area.

The fuzzy picture above is my first photograph of a Western Meadowlark. They were very much in evidence, as their calls could be heard every place we stopped, but they were shy about being approached, so this one was taken with a 30x zoom (lest you think I have sophisticated equipment, that is optical and digital zoom together).

The second bird shot is the exceedingly common and obviously-named Redwing Blackbird. These were a couple of guys hanging out, hoping to pick up some ladies. The females are decidedly not well-named, being more drab brown without the red wing spots.

Thursday, April 8, 2010

Our Mascot Arrives!

Christmas comes early...or late! What in the world could be delivered in a box like this? It weighs a lot, and it really doesn't fit in our storage room, but hey, a big gift is a big gift, no matter that it is April. A few dozen screws later, and some heavy lifting of plywood slabs, and our treasure is revealed!

It's a full-scale model of a Smilodon californicus from the La Brea Tar Pits in Southern California. We selected this creature to be one of the focal points of our Community Science Center that will "soon" be constructed on our campus (yes, there are the inevitable delays). The building will house the physics, chemistry, biology and earth sciences programs, a planetarium, an observatory, and best of all, the Great Valley Museum (currently 'housed' in a refurbished old house). We picked it for several reasons: it is the state fossil of California, it lived in our immediate vicinity, and it will have a lot of the "Wow!" factor that will make the center a great place for kids to visit. Our building is being built with bond issue funds, but the Smilodon was purchased with donations and fundraisers: we sold barbecued burgers to the modern day carnivores on our campus to purchase this extinct carnivore...

Several months ago I blogged about the Smilodon as part of my "Other California" series. A portion is repeated below:

"Prior to 12,000 years BP, our state would have been an intimidating place. Packs of Dire Wolves and American Lions roamed our prairies, seeking their prey from among the herds of horses, camels, antelope, bison, elk, mastodons, and mammoths. Short-faced bears, larger than grizzlies and polar bears, would have at least considered having you for lunch. In more forested and brushy areas, the large plant-eaters faced a threat from one of the most intimidating predators of all, the saber tooth cat (Smilodon californicus).

The largest cougars today weigh in at 200 lbs or so. The saber-tooths were more like 700 lbs or more! They were heavily built, especially in the front, giving them in advantage in stealthy ambushes. Their dagger-like serrated fangs could be 11 inches long. They didn't waste time chasing their prey, they jumped, bit, and waited for the victim to bleed to death. Evidence suggested they worked in social units, somewhat like wolves (many specimens show evidence of recovery from broken bones that would have led to the death of solitary predators).

The La Brea Tarpits in Los Angeles provide one of the richest records of the Ice Age predators to be found anywhere in the world. Trapped plant-eaters attracted large numbers of predators to the pools of sticky tar, and the hunters were trapped as well (something like 90% of the specimens recovered are predators). Portions of 1,200 saber tooth individuals have been found so far, allowing for all manner of population variability and growth studies to take place.

From about 1.6 million years until just 10,000 years ago, the sabertooths and other large animals dominated the ecosystem of California. Their disappearance is linked to severe climate changes in the aftermath of the most recent ice age, or to overhunting by newly-arrived humans. The issue of the North American megafauna extinction is one of the more intriguing mysteries of the present day.

The Smilodon californicus was selected as the state fossil of California in 1973, beating out the trilobite species Fremontia fremonti for the honor. I understand the desire of many of the paleontologists to have a trilobite named the state fossil, but I must say I get a lot more oohs and ahs from elementary students when they see my Smilodon skull during their visits at the department. They are absolutely fascinated to find that the animal once lived, quite literally, in their backyards. So do I!"

So it's here now! All we need is a building to put it in...