Archives
Geology Picture of the Day - Pahoehoe
Posted on Wednesday, May 14, 2008 @ 8:19 am by Dave Schumaker
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.
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.
Volcanic Smog on Hawaii
Posted on Monday, May 5, 2008 @ 2:05 pm by Dave Schumaker
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.
The Red Dirt of Kauai
Posted on Sunday, May 4, 2008 @ 11:51 pm by Dave Schumaker
One of the things that the island of Kauai is famous for, is its very vibrant (and somewhat annoying - if you get it on your clothes) deep red dirt. One popular application of the dirt is its use in dyeing t-shirts, the most well known of which are Dirt Shirts.
What causes Kauai’s dirt to be so red? Since Kauai is one of the oldest Hawaiian Islands, the high iron content of the volcanic soils has had plenty of time to oxidize, especially with the wet conditions of the island (Kauai is home to one of the wettest places on the planet).
Geology Picture of the Day - Waimea Canyon
Posted on Friday, May 2, 2008 @ 1:03 pm by Dave Schumaker
I’ll admit that for the most part, my choices for the geology picture of the (almost every-) day have no rhyme or reason. However, today’s picture is actually relevant in my opinion. It’s a beautiful picture of Waimea Canyon on the island of Kauai. And why is this relevant? I will be flying to Kauai tomorrow for a vacation with the family.
I found a nice little website about the geology of Kauai, along with a cross section and a geologic map, located here. A simple description of the canyon is also available here.
Waimea Canyon is the largest canyon in the Pacific and truly a dramatic sight to behold. The canyon measures 10 miles long, 1 mile wide, and more than 3,500-feet deep. It was carved thousands of years ago by rivers and floods that flowed from Mount Waialeale’s summit. The lines in the canyon walls depict different volcanic eruptions and lava flows that have occurred over the centuries. Even though smaller than the Grand Canyon of Arizona, Waimea Canyon rivals the beauty.
Geology Picture of the Day - Ash Cloud at Kilauea
Posted on Thursday, March 27, 2008 @ 11:30 am by Dave Schumaker
I thought I’d continue the theme of volcanoes and Hawaii by featuring this photo taken yesterday at the Halema’uma’u Crater on Kilauea.
The Hawaiian Volcano Observatory has more pictures and information.