Volcanoes

A type of lava formed from very fluid basaltic flows is called pahoehoe. In today’s geology picture of the day, we see a beautiful example of ropey pahoehoe from Hawaii Volcanoes National Park.

Image Credit: bgustus2000 on flickr.

For more information on the types of lava, visit Instant Hawaii.

One of the more interesting types of pahoehoe lava is called ropey pahoehoe and looks like a series of twisted ropes spaced evenly along the ground. The twisted ropes may be fairly straight, or may loop and wind in and out much like a fingerprint. Many visitors express interest in what could create such an unusual shape, but once you see ropey pohoehoe lava being created it is instantly clear how the shapes occur. As the pahoehoe flows, it usually encounters some minor barrier that slows up the front of the flow. As the front of the flow is slowing down, the faster flow behind it pushes the front and forces it to create a small ridge, which it pushes up and over the barrier. That ridge begins to cool and creates the next barrier, which in turn creates the next. The result is a series of ridges interspaced with valleys - which looks like 4 inch thick ropes of lava laying side by side or looping side by side. To walk over ropey pahoehoe it is best to walk on the top of the ridges, perpendicular to the ridges.

Today’s geology picture of the day is from the ongoing Chaiten eruption (which started unexpectedly at the beginning of this month in Chile). Ralph Harrington at The Volcanism Blog has been providing wonderful updates on the eruption.

This photo was captured on May 6 and shows electrostatic discharges as a result of the ash cloud above the volcano.

Image Credit: Carlos Gutierrez

The third episode of the GoodSchist PodClast has been published today. This episode features Chris Town, Ron Schott, Brian Romans and Ralph Harrington.

Show notes for Episode 3 are available on Chris’ webpage and relevant links have been posted on the newly created PodClast del.icio.us account.

I really think the PodClast is starting to come into its own and has done a great job featuring various personalities in the Geoblogosphere and discussing a wide range of topics. Bravo to Chris and the gang. You can subscribe to the PodClast via iTunes here.

[Via GoodSchist]

The recently created vent on the Big Island of Hawaii has seen a lot of activity and has forced the closure of the Hawaii Volcanoes National Park multiple times over the past few months. The Volcanism Blog has had some excellent posts about Hawaii and the new activity as well.

An article out today, written by the Associated Press, talks about the issues facing farmers and residents of the Big Island and their struggles dealing with the volcanic smog (called vog) created by the new vent. The increased levels of sulphur dioxide and a change in wind direction have forced evacuations and killed various crops.

Big Island crops are shriveling as sulfur dioxide from Kilauea wafts over them and envelops them in “vog,” or volcanic smog. People are wheezing, and schoolchildren are being kept indoors during recess. High gas levels led Hawaii Volcanoes National Park to close several days this month, forcing the evacuation of thousands of visitors.

Residents of this volcanic island are used to toxic gas. But this haze is so bad that farmers are thinking about growing different crops, and many people are worrying about their health.

Kirk Brewer, 33, an electrician who moved to the Big Island in 2006 from Southern California, blames his headaches and wife Tracy’s itchy skin, sore throat and runny nose on the vog.

“It’s a bummer when you go to the other islands and see how clear and blue it is, but we’ll just deal with it,” Brewer said.

Image Credit: brandilnm on flickr.