To the Boston Bomber(s)

You’re a fucking coward, whoever you are.

I don’t know who you are. I don’t know if you’re a domestic or foreign coward, or a single coward or many. Doesn’t matter. I don’t need your name and your back story to know you’re a fucking coward. Only cowards plant bombs where innocent people and children will be out enjoying a race. Only cowards run away so they don’t have to deal with the aftermath of what they’ve done.* Continue reading “To the Boston Bomber(s)”

To the Boston Bomber(s)
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50 “Simple” Questions, Me Arse

I thought we were in trouble. Guy P. Harrison’s introduction to his new book 50 Simple Questions for Every Christian set alarm bells a-ringing. “This book is not an attack on Christian people,” the first line says. Fair enough. But then there were all sorts of weaselly, mealy-mouthed words that seemed to shout “Retreat!” “Humble and far less threatening,” forsooth. “Clichéd and cartoonish angry atheist attack on crazy Christians,” indeed! “No interest in scoring debate points,” even so! “Proud to say I’ve walked away on friendly terms,” for fuck’s sake. Despite assurances punches would not be pulled, I was positive I was in for 324 pages of forelock-tugging, bowing and scraping deference to Christianity. This looked like it was going to be one of those kumbaya books, and I almost packed it up and sent it back to Prometheus Books with a note saying, “No. I can’t do this.” Continue reading “50 “Simple” Questions, Me Arse”

50 “Simple” Questions, Me Arse

Halp! We Need Kittehs for Evelyn!

Our own Dr. Evelyn had quite a scare recently – some asshole broke in to her flat and stole her laptop. She wasn’t harmed, but she’s considerably shaken up and in need of an infusion of kittehs. Send her your cute kitteh photos asap! You can reach her at geokittehs at gmail dot com. We’ll take them all, the more the merrier. Someday, they may even achieve some fame as Geokittehs!

Misha imitating a boulder in a stream bed.
Misha imitating a boulder in a stream bed.
Halp! We Need Kittehs for Evelyn!

The Mystery Fault, Part 3

In Part 2, we’ve established that the Silver Creek fault is, in fact, the southwestern boundary of the Evergreen basin.  But what’s it doing there, anyhow?  Back sometime around 10 to 15 million years ago, an early Hayward fault formed (an estimated 100 km (62 miles) south of where it is now) with a right stepover in the southeastern most end of it.  Basically that’s where a fault  stops and then starts again some distance away, in this case to the right.  .Now, both the Hayward and the Silver Creek faults are right-lateral strike-slip faults.  This means if you stand facing the fault, and it slips, the ground on the other side of the fault will move right.  When you have a right step in a right-lateral fault system, it tends to pull the ground between the faults apart like so:

pullApartBasin

And thus creating a pull-apart basin.  So the basin started to be created in the Miocene.  Since then there’s been 175 km (109 miles) of slip on the Hayward Fault, of which 40 km (25 miles) of slip was on the Silver Creek fault itself.

Now, the Hayward fault is a very active fault.  Parts of it are creeping at the surface, but the whole fault system is locked at depth right now and is one of the prime candidates for the next Northern California Big One.  Scary thought, and keeps geologists and emergency managers awake at night.  But what about the Silver Creek fault?

Well, it turns out that about 2 million years ago, give or take a few thousand, the slip that was happening on the Silver Creek fault moved over to the Calaveras fault, which runs east of the Hayward fault.  (See the faults pic in Part 1.)  That doesn’t mean the fault isn’t still moving, but it’s moving at a much slower rate than the Calaveras and Hayward faults, and probably won’t generate any big earthquakes. Probably.

There’s some evidence for a couple of magnitude 6-ish quakes in 1903 down near the south end of the Silver Creek fault, but they’re not very well located, and it could very well be that they were produced by the Calaveras or another fault.  Because there is another fault, one that I haven’t talked at all about yet, and which is completely buried and only inferred.  But there’s some pretty decent inference for inferring it.  I’ll talk about it in Part 4.

Meanwhile, those of you who live in California, there are fault systems in both the northern and southern parts of the state primed to go off and produce the Next Big One.  Plan for a few days of food, water, no electricity, etc.  Expect cell phone systems to be down.  Expect land lines to be overloaded.  Expect hospitals to be backed up.  But, as Douglas Adams says, don’t panic.

 

References:

Wentworth, C.M., Williams, R.A., Jachens, R.C., Graymer, R.W., Stephenson, W.J., 2010, The Quaternary Silver Creek Fault Beneath the Santa Clara Valley, California, U.S. Geological Survey Open File Report 2010-1010, http://pubs.usgs.gov/of/2010/1010/, accessed 4/9/2013

 

 

The Mystery Fault, Part 3

Geologists vs. the Rest of the World

My heart sister Nicole posted this for me on Facebook. She knows me entirely too well. The moment I saw it, I fell deeply in love, and knew I had to share it with you. I think you lot will love it as much as I did:

Image courtesy ROFLrazzi via Nicole.
Image courtesy ROFLrazzi via Nicole.

That whole damned thing is so very, very true. But the neat thing is when we eventually influence the people around us to the point where they can spot some of the basics with ease. Nothing warms my heart more than to know that I’ve given someone a new way to see the world. Keeps the place interesting and the horizons broad, doesn’t it just?

And memes like this can open the door to a dialogue. A little laughter combined with awe and a hefty dash of enthusiasm make a very potent brew indeed.

Geologists vs. the Rest of the World

New at Rosetta Stones: A Reprise

I’m a bit frantically busy round here this week, so I haven’t had time to write much. I promise we’ll return to Mount St. Helens soon, but in the meantime, I’ve reprised one of my favorite posts. If you missed “Time and Space, Space and Time” the first go-round, go have a gander. I think you’ll like it.

New at Rosetta Stones: A Reprise

The Mystery Fault, Part 2

In Part 1 I gave you the setting of the Silver Creek fault.  Here I’ll talk about how scientists at the U.S. Geological Survey figured out where the buried part of the fault runs.

The earliest (I think) tool these scientists used to analyze the geology of the Santa Clara Valley was gravimetry.  Gravimeters, developed in the ’70s-’80s time frame, measure gravity to such a fine degree that they can be used to determine what’s underground.  Valleys are usually covered, and to some extent filled in, with alluvium that local streams have eroded out of the surrounding hills/mountains.  They can get very filled-in, because over time what’s loose-ish near the surface compacts under the weight of the overlying alluvium and subsides.  This makes more room for more alluvium!  But still, even the compacted alluvium is not as dense as the surrounding mountain rocks.  A gravimetry survey  can distinguish rock from alluvium — and the deeper the alluvium, the lower the microgravity.   First, here’s the Google Earth map of the modern Santa Clara Valley:

SCValleyToday

And here’s the microgravity map of the Santa Clara Valley:

gravity

 

By golly, there are TWO valleys under some of that alluvium!  The one on the northeast, with all the deep, deep blue areas, is called the Evergreen Basin.  And while we now know that it is bounded to the west by the Silver Creek fault, that wasn’t known when the gravimetry survey was done, it was just suspected.  (Sorry about all the  “after” photos, but these guys like to publish when they’re certain they know what they’re talking about.)

The next clue, which I used to have a pic of, but can’t find, is about hydrology.  The Santa Clara valley, before it was Silicon Valley,  was an ideal place to grow fruit trees.  The whole valley was filled with agricultural activity.  And since it doesn’t rain in coastal California in the summer, they pumped groundwater to water those trees.  A lot of groundwater.  When towns and small cities started to spring up, and grew, and grew, they pumped more and more groundwater.  There wasn’t that much to pump.  Land started subsiding.  In downtown San Jose, it subsided as much as 16 feet in some places.  Obviously, this couldn’t last, and the valley now gets its water from the rivers that drain the Sierra Nevada mountains and cross California’s Central Valley.  There’s still pumping going on, though, and percolation ponds to counteract it; that’s just how the water is managed. So every summer there’s a couple of centimeters, give or take, of recoverable subsidence.  Except it STOPS, to the east, at an invisible barrier.  There’s this annual subsidence in San José… but it abruptly stops at the boundary of the Evergreen Basin.  Any geologist worth her hammer would be yelling, “fault!”   Faults often form hydrologic barriers.  So that’s the next piece of evidence for the Silver Creek Fault.

To really determine whether the barrier is a fault, the U.S.G.S. decided to run a seismic reflection profile.  To do this, they run a line of sensors designed to detect seismic reflections.  Then, using a truck with a BIG weight in the back, they smack the ground really hard. This makes a seismic disturbance that is reflected back from the different layers of alluvium and rock, to give an idea of where layers are beneath the surface.  What makes these layers?  They’re simply layers of slightly different composition of alluvium — sand vs. clay, for instance — or in rock, changes in rock type or rock density.  In valleys like the Santa Clara where all the alluvium has been deposited by streams, layers naturally vary in density and composition, as streams move around, have floods, create graded banks, and carry on like this for thousands of years.

Now, this wasn’t the first, nor the last, seismic reflection profile that has been done in the Santa Clara Valley, but what makes it unique is that it was done through downtown San José, against the backdrop of lots of other seismic disturbances: big trucks, construction, trains, etc.  But the smart geophysicists were able to filter out most of that, and produce this profile:

reflectionProfile

 

All the squiggly, mostly horizontal lines are reflections from various layers.  Just to make sure you can’t miss it, they’ve marked the Silver Creek fault in red;but if you look closely, you can see it in the profile.  To the left of the line is the “noise” that comes back from solid, uniform-composition rock; to the right is the multitude of little lines that represent alluvial layers.  “Franciscan Basement” refers to rocks of a group named “Franciscan”.  You can see there’s no nice, gradual, left edge to the Evergreen Basement; the transition is very abrupt, and clearly indicates a fault.  Bingo!  The Silver Creek Fault forms the western boundary of the Evergreen Basin.

Great.  So there’s proof that the Santa Clara Valley — Silicon Valley — has its very own fault, a less than reassuring thought to the people who live and work here.  So what kind of fault is it?  Has it moved a lot in the past, and will it do something nasty any day now?  Stay tuned for part 3.

References:

Wentworth, C.M., Williams, R.A., Jachens, R.C., Graymer, R.W., Stephenson, W.J., 2010, The Quaternary Silver Creek Fault Beneath the Santa Clara Valley, California, U.S. Geological Survey Open File Report 2010-1010, http://pubs.usgs.gov/of/2010/1010/, accessed 4/9/2013

 

 

 

The Mystery Fault, Part 2

Hey, Richard Dawkins! Women Aren’t Invisible

So stop treating us like we are.

Really, you only seem to notice women when you can use them to conveniently bludgeon religions. You’re super-concerned about how women are treated in the Muslim world because Islam. You call the Judeo-Christian god a “misogynistic…bully,” because hey, great point of attack, amirite? So women might get the idea you’re on their side, but when it counts, when we’re fighting against sexism and misogyny in the atheist community, you “Dear Muslima” us. When it comes to abortion rights, you’re more for pigs and parasites than you are women. You don’t see us, actual human beings with fundamental rights to bodily autonomy and respect. You see a rhetorical device. And you don’t even seem to be aware you’re doing it. I hope you’re not. I hope you’re not the kind of man who would deliberately erase a woman from the picture. But unintententional or no, that’s precisely what you’re doing.

How the religious right (and, later in pregnancy, Richard Dawkins) view pregnant women. All they can see is a fetus.
How the religious right (and, later in pregnancy, people like Richard Dawkins) view pregnant women. All they can see is a fetus.

Continue reading “Hey, Richard Dawkins! Women Aren’t Invisible”

Hey, Richard Dawkins! Women Aren’t Invisible

Lovely Birdies of Bothell, Plus Undignified Kitteh Pics

It’s a fantastic time of year, my darlings! The birds are out and about, singing lustily as they endeavor to find someone to perform one of the three Fs with, and the new leaves aren’t big enough for the feathery bastards to hide behind. For someone trying to photograph something other than waterbirds, this is outstanding.

I went up to that bit of North Creek a couple miles from my house that has a possible blueschist wall, and one of the first things I spotted was this magnificent towhee. At least I think it’s a towhee. Tell me if I’m right. Continue reading “Lovely Birdies of Bothell, Plus Undignified Kitteh Pics”

Lovely Birdies of Bothell, Plus Undignified Kitteh Pics