Lassen Peak
eklemetti | July 4, 2010So, I've had requests on the blog to help to do some defining of volcanologic terms on the blog, so I thought I'd try a new column called Eruptions Word of the Day. I'm not sure how often it will run, but let's give it a try.
Eruptions Word of the Day for July 5, 2010: Dacite
Dacite is a magma type defined by silica (SiO2) content between 63-68 (or 69) weight percent. That is the textbook definition, but some other typical characteristics of dacite lavas (or magmas) is the presence of certain minerals: plagioclase feldspar and hydrous minerals (containing water in their mineral structure)…
eklemetti | October 17, 2008
The only volcanic arc in the lower 48 states continues to be pretty darn quiet according to the USGS. The Cascade range that spans from Lassen Peak in the south to Mt. Baker in the north (and maybe Mt. Garibaldi in Canada) has been remarkably quiet in terms of eruptions for the last century. In fact, only Mt. Saint Helens and Lassen Peak have erupted since 1900 - and most of the volcano have shown very few signs of even coming close to eruption beyond minor seismic swarms, steaming or land deformation. This is in contrast to the reports from the 1800s that suggest that Hood, Shasta, St.…
eklemetti | October 13, 2008Â
Â
Â
I'm a little behind on the news after spending the weekend field tripping at Lassen Peak. I'll be catching up soon, but to tide you over, here is a picture I took of some bubbling mudpots/springs at Bumpass Hell near Lassen Peak. The dark areas are pyrite crystals floating on the stew!
eklemetti | August 30, 2008
I am back from my trek through the Oregon and California Cascades - including stops at Lassen Peak/Chaos Crags, Hood, Three Sisters and Crater Lake (an added bonus). I'll try to catch up on the volcano news I've missed and post on anything exciting that happened soon, but otherwise I'll be posting new news as it occurs.
In the meantime, here's a picture I took of Rock Mesa (foreground) and South Sister (background) taken from the Pacific Crest Trail. Rock Mesa is a ~2,700 year old rhyolite flow that appears to have erupted multiple pumices and has some impressive flow banding of the rhyolite…
eklemetti | August 19, 2008
I will be away from Eruptions for the next 2 weeks or so. I won't be on vacation, I will actually be out on volcanoes themselves doing some much-needed fieldwork. It is a three volcano tour, starting with a trip to Lassen Peak to get a guided view with Michael Clynne of the USGS (the world expert on the volcano, the last Cascade volcano to erupt other than Saint Helens).
Then follows a trip to Mt. Hood with Adam Kent from Oregon State (my doctoral alma mater) in Oregon to sample some of the youngest flows that are only a few hundred years old. Geologists from Oregon DOGAMI (Department of…