Friends of volcano monitoring on Facebook

I forgot my Facebook password the day after I signed up, so I can't join this. But the rest of you technologically hip people can!

Facebook friends of Volcano Monitoring

I think Maria is responsible for the creation of this group.

Edit: Maria says she wasn't responsible for setting it up - they just referred to her post to explain the group.

Artistic* response to Redoubt and Asama alerts

* Kindergarten art, that is.

My five-year-old was looking on while I read the geology blog feed this morning, and was impressed by the images of Redoubt and Asama on Eruptions and The Volcanism Blog. So he responded with his own volcano art:



Those are two giant rivers of lava on each side of the volcano, and an extremely shallow sill feeding the eruption. And I think the magma chamber is sitting on top of a loosely packed gravel deposit. This is the first of four pictures, which illustrate show lightning strikes that penetrate into the mantle, a gigantic landslide (which somehow ends up on the opposite side of the volcano from its scarp), and a hurricane that eventually cools the lava.

This may be evidence that my child will grow up to work on a combined re-make of Dante's Peak, Volcano, and In the Path of a Killer Volcano.

(By the way... why does WGBH have a picture of Pu'u O'o on the cover of a movie about Pinatubo now? The original image was the right volcano, if I remember correctly. BTW, if anyone is looking for a good volcano movie to show in class, I recommend In the Path of a Killer Volcano, even with the wrong volcano on the cover. Real life is more dramatic than fiction in some cases.)

Horizontal columnar jointing, Wolf Creek Pass

Callan's post about columnar jointing and rust blisters reminded me that I've got a photo that I've been meaning to show since the 2007 GSA meeting.

Driving from Durango to Denver means crossing at least three passes. My favorite one is Wolf Creek Pass, over the Continental Divide in the San Juan Mountains. After several years of roadwork, there are some fresh roadcuts on the western side that show mostly a lot of young sediments, but some volcanic rocks, as well. This one caught my eye as I was driving up to the pass:


It's a dike cutting through pretty loose sediments - not surprising for the rocks in the eastern San Juans. But what caught my eye was the fracture pattern:


Those are horizontal columnar joints. As Callan showed in his photos, most columnar joints are nearly vertical. But that doesn't have anything to do with gravity - it's the result of cooling of a near-horizontal layer, like a lava flow. The joints form perpendicular to the cool surface. And in the case of this dike, the cool surface is vertical.

This is a neat roadcut for other reasons, too. There's baked sediment at the contact with the dike. And the sedimentary structures are nice, too. Even a squashed-rock person like me can make out some old channels, and the clasts in the conglomerate are volcanic rocks. I don't know if either the clasts or the dike have been dated, but I bet there's a pretty short time between deposition of the sediment and intrusion of the dike.

Happy New Year, everyone!

Earthquakes, volcanoes, and landslides in Japan

The rural setting of Saturday's M 6.8 earthquake in northeastern Honshu, Japan* has fortunately meant that many fewer deaths occurred than during the 1995 Kobe earthquake. (From news reports and photos, it looks like landslides were responsible for a lot of the destruction. Dave's landslide blog has photos.)

So the surface is where the destruction is, but I'm also interested in what's going on deeper down. If you use the Google Earth plug-ins for the USGS real-time earthquakes and the Smithsonian Institution's volcanoes, you can see where the fault is compared to the volcanic arc:



It's in the arc. Right in the middle of the arc. One volcano, Kurikoma, lies above the aftershock zone. And it's acting up. (News report here.)

So here are my somewhat random thoughts:

- The earthquake was along a thrust fault. I know of arcs that are extensionally collapsing, which involves normal faults. (The Marianas arc is a good example.) I know of arcs with strike-slip faults running through the line of volcanoes. (The Sumatra fault, for instance, is like this - there's a strike-slip fault that runs along the arc, so the plate movement is partitioned into two zones - subduction at the trench that caused the 2004 tsunami, and strike-slip movement within the arc.) And I know of studies (including one of mine) arguing that thrust faults moved during the growth of ancient plutons. But modern thrust faults in the middle of arcs - not thrust faulting partitioned into the wedge above the subduction zone, or in the back-arc (like in parts of the Andes) - I'm not sure if I've seen a thrust earthquake in an arc before. I know there are thrust earthquakes in the Sea of Japan, and that there is compression between Japan and Asia, so the fault mechanism isn't surprising. But the location is. Is this a case where the magmatism created a weaker zone in the crust and allowed thrust faulting to take place?

- Did the earthquake (either due to stress changes, or due to the passage of seismic waves) cause Kurikoma to start acting up?

- What's going to happen next?

* The Japan Meteorological Agency measured the earthquake as magnitude 7.2, but I don't know which magnitude scale they're using for it. I would rather use moment magnitude consistently to think about earthquake size, and I know that's what the USGS is reporting, so I'll stick with that.

Links: drought in Turkey & SE US, Tambora, visualizing climate change

Some links to things I've been reading (and thinking about for classes):

RealClimate has a guest post from Figen Mekik about climate change and drought in the Mediterranean. It's a great combination of a personal perspective (Mekik is originally from Turkey) and explanation of the processes involved. In particular, Mekik explains the North Atlantic Oscillation, which I've always found confusing... but which is kind of an Atlantic version of El Nino, and which can have an important impact on weather in Europe, North Africa, and North America.

John Fleck has been watching the drought in Georgia and blogging about what the historical record shows. Is the problem with climate, or with population growth, in this case? (The definition of drought, after all, depends on how much water a given area needs.)

For anyone who, like me, needs a good source of images for climate change lectures: the global warming art site. I recognize the graphs from the peer-reviewed literature (and the wiki pages associated with them have all the references). And it's really nice to have access to the graphics in color, and in an easy format for importing. (Thanks to Michael Tobis and John Fleck for the links.)

And, finally, remembering "the year without a summer" and the eruption of Tambora. I heard the story on NPR this morning while I was driving in. In 1816, people starved in Europe, and New England had snow in the middle of the summer... all because of the eruption of a volcano on the other side of the world. Tambora's eruption was bigger than Krakatoa's (which also had a cooling effect later in the century). (Thermochronic had a great post about Tambora, as well, and connected it to the writing of Frankenstein and with landscape paintings.)

spectacular volcanic eruption photo

An amazing photo of the volcano Tungurahua (in Ecuador) was posted as today's Astronomy Picture of the Day. (I'm going to link rather than posting the picture; the picture is copyrighted.) You can see lava flows pouring down in all directions, and a blast of dark tephra blowing off to the side. You can see the prevailing wind direction on the photo, too: the wispy clouds (almost lenticular?) are typical of clouds on the windward side of a peak, and there is a little snow on the windward side, as well.

The photo was taken by Patrick Taschler, who has other really beautiful photos of the eruption animated on the front page of his site.