tectonics
eklemetti | November 5, 2009 Lava flows from the 2005 Mando Hararo eruption in Ethiopia.
Alright, I had been attempting to ignore this story because it was, well, a little uninteresting at first, but it apparently has legs so I will tackle it.
Slashdot has a post proclaiming:
'Volcanic activity may split the African continent in two, creating a new ocean, say experts. This is due to a recent geological crack which has appeared in northeastern Ethiopia.'
OK. Where do I start?
This is based on a recent study published in Geophysical Research Lettersthat found that the recent volcanism in Ethiopia is related to the active…
khannula | September 2, 2009I've spent 15 hours in the classroom teaching in the past three days, and several more meeting with students to sort out schedules and brainstorm ideas for senior thesis projects. My brain is fried, but I'm going to try to share some interesting stuff I've run into:
- Early this afternoon, I posted a frantic plea for good Google Earth locations to use to demonstrate tilted rock layers in my first Structural Geology lab. I should have just checked SERC first. They now have a collection of images and latitude/longitude coordinates that are both beautiful and beautifully deformed. I started my…
khannula | July 28, 2009Last month, another structural geologist came to town to check out possible sites for a future field class. While we were out looking at one of my favorite teaching sites, he commented that geologists seem unusually willing to share their secrets with one another. (We had met at one of the Cutting Edge workshops, where great teaching ideas are free for the taking, technically unpublished but shared online and in person.)
A few weeks ago, I learned about another example: Outcropedia, a project of the International Union of Geosciences' TekTask group. From the organizers' e-mail:
The…
khannula | June 8, 2009Much of the celebration of World Oceans Day focuses on the ocean's importance as an ecosystem, especially in relation to climate change. But the bottom of the ocean is still relatively unknown - I've been told by marine geologists that we know the topography of Venus better than that of our own planet, because we know so little of the ocean floor. The little that we learned before the late 1960's transformed the understanding of geology on land, as well - if it weren't for exploration of the oceans, we wouldn't know about plate tectonics.
So in honor of World Oceans Day, I give you links to…
khannula | June 7, 2009I bet I'm not the only geologist who always wants to list "time machine" in the budget request for every grant proposal I write. Yes, we've got a lot of tools to sort out what's happened in the past, but wouldn't it be a lot easier if we could just go back and see for ourselves? So I love this month's theme for the reactivated Accretionary Wedge carnival.
I want to go back about 1.7 billion years, to see what on Earth was happening when my favorite local rock was being deposited.
This is the Vallecito Conglomerate. It's been metamorphosed, but its sedimentary features are still preserved. It'…
khannula | May 30, 2009I made a promise to myself that every month, I would at least look through the abstracts on my RSS feeds and note interesting articles that I wanted to find time to read. So now it's May 30, and I'd better do it before the June issues come out.
So... articles in the May issue of Geology that look interesting:
Extensional tectonics: Extension rates, crustal melting, and core complex dynamics. Metamorphic core complexes are made up of metamorphic and igneous rocks that have been brought nearer to the surface by continental extension. They're characterized by mylonites that separate the hotter,…
khannula | April 6, 2009The estimated death toll from last night's M 6.3 earthquake in Italy is currently 150, with 10's of thousands of people left homeless. My thoughts are with the people there, especially those still searching for their loved ones.
As you can see from the USGS map and moment tensor (and from Highly Allochthonous, who posted a great explanation while I was on kid duty), the earthquake occurred on a normal fault associated with the collision of Africa and Europe...
At this point, if you've taken an intro geology class, you're probably shaking your head, wondering if I've made a mistake reading…
esiegel | April 21, 2008What makes earthquakes? Although there are many causes, including volcanoes, the most common thing that causes them are tectonic motions, which also cause tsunamis. But as valuable as it is to understand other planets in our solar system and in other star systems, sometimes it's important to understand what's going on inside our own planet.
The crust of the Earth actually is made up of a number of plates, which rub against one another and move over time. Who's to blame? I fault the liquid hot magma.
So what happens is that these plates slip against each other in one of three ways, as shown…