Brienna Geology Blog

One day, as I was walking home from work, I decided to take the long, scenic route home. There was not a lot to see as I walked so I let my mind wander. I absentmindedly began thinking about the article I had just read on karst topography and how, in places such as Southern China, Puerto Rico, and Cuba, the karst development is so advanced that there are tall, immense, tower karsts  just dotting the landscape, formed by the slow, but powerful  groundwater eroding the limestone in that area. "Nothing interesting like that around here," I mumbled to myself.  Famous last words. At that moment, I knew that something wasn't quite right and before I could do anything I found myself a good 20 feet lower than I had previously been. The ground I walked on had literally just broken beneath my careless feet. As I slowly moved my body around to make sure nothing was hurt or missing, I looked around me. I seemed to have landed in a cavern , an underground chamber. I wondered how...

Elk City, Idaho, February 18, 2016 http://www.idahostatesman.com/news/state/idaho/article61300727.html http://kutv.com/news/nation-world/video-massive-landslide-blocks-idaho-highway-hundreds-trapped-in-town Watch from about 1:45 on for the exciting stuff. (Warning: there is some swearing) This is a landslide that happened in Elk City, Idaho last February. From what I read, debris made its way to the road fairly frequently and transportation employees would clear it off. However, when they went to work this day, the slope was still visibly moving. As you saw in the video, it started out pretty slow, but still visible, then it got very fast. This landslide cut off the only road in and out of the small town of 250 people, leaving them stranded. Later, an emergency road was opened up for a short period of time.  I think this would be classified as a transitional slide mass movement. It appears to move down a flat surface, maybe a bedding plane. It is not viscous enoug...

I chose to trace the Mid-Atlantic Ridge because it was very obviously a ridge. Once I completed the elevation profile, I could clearly see it was almost like a big mountain beneath the ocean, which I thought was awesome, but also weird to try and picture. (I started imagining hiking underwater and coming to this gigantic mountain range.) The profile was very rugged, which would be due to the slow spreading at that boundary. This also means there is usually a rift valley, but I had a hard time finding that. I saw two depressions on either side of the ridge, but I wasn't sure if they were rift valleys. My hypothesis is that they are parts of a former rift valley and the ridge has fairly new crust that hasn't rifted yet. The other thing I labeled was the age of the seafloor. It's pretty easy to see the symmetry on either side of the plate boundary. I drew a line on this picture that is approximately where the elevation profile is and used this to place labels on my origin...

There were not any earthquakes extremely close to Rexburg, but there were a couple that were fairly close. Both earthquake hypocenters were fairly shallow, between 0-33 km deep. The first earthquake is to the northeast of Rexburg. This was east of West Yellowstone Montana, in Yellowstone National Park. This one did not surprise me at all because it is right near a hotspot where there is a lot of tectonic and seismic activity.  The second earthquake that is pictured south of Rexburg was near Soda Springs Idaho. I honestly was surprised to see this one. I cannot think of any obvious reason why an earthquake would have occurred there. It is not very close to the hotspot, or a plate boundary which are places where earthquakes are frequent. However, the textbook said that an intraplate earthquake like this one could be caused by internal stress buildup due to the interaction of neighboring plates.  Overall, I feel as safe as I did before starting this assignment....