I’ll be posting more starting in December (post-finals week). I’ve got a little too much on my plate at the moment. I’m blogging for PSU! Check it out.
Not having experienced an earthquake above a 3 on the Mercalli scale, I was surprised to learn that there are several types of earthquake waves. It felt to me that the shaking was only occurring from side to side, but this is not the case.
The two main types of earthquake waves are body and surface. Body waves pass through the earth, while surface waves travel along the surface. The way in which waves travel depends on several factors including the local rock composition and the depth of the earthquake.
The two types of body waves are P and S waves. P waves are usually the first to be detected. They are compressional waves and move in the same way that sound waves move. Like sound waves, they can travel through solid, liquid and gaseous materials. This also means that they can travel quite far.
The second type of body wave is the S wave. These waves are usually slower and can only propagate through solid or semi-solid materials; anything that has the ability to “spring back” to it’s original position.Love waves are surface waves. The motion of these waves is similar to that of S waves and they cause the ground to move in the side to side motion that I mentioned earlier. Looking at the diagram, it’s easy to see how these waves would be detrimental to the structural integrity of foundations.
In my opinion, the most interesting type of seismic wave is the Rayleigh wave. These are exactly like the waves propagated on the surface of the ocean; they cause solid material to move in the same way as a liquid. The ground literally rolls in waves.
This is an awesome book and easily one of my favorites. The book is fantastic because you don’t need to have a deep or vast prior knowledge of science to enjoy it, but if you do, you’ll still love it. Bill Bryson is an American, but has a dry and very British sense of humor, which he must have picked up while living in the UK. If you’re looking for some summer reading, A Short History of Nearly Everything should definitely be on your list.
Click for the National Geographic article.
The eclipse will last up to two hours, which is quite long for this type of cosmic event. The next eclipse of this magnitude won’t occur until 2018. Sadly, we won’t be able to see it here in North America. December 10th will be the next lunar eclipse we’ll be able to observe.
has been the topic in lecture for the past couple of weeks. My husband was wondering why the road up to some of our favorite hiking spots has been closed….here is why.
In looking at this, I believe it to be an earthflow, although it could also be a slump. The road being in the way makes it difficult for my novice eye to differentiate.
“Ever since woolly mammoths have been found frozen in permafrost the possibility of cloning this extinct species has given rise to questions:
* Is it moral and ethical to do so?
* Is it feasible using such ancient DNA?
* Do we have the knowledge to succeed?
* Are cloned extinct species the same as reintroduced species?”
These are interesting questions. Personally, I don’t think that cloning a mammoth would be unethical unless the animal was mistreated. However, the vast grasslands that mammoths need to survive are no more on the North American continent and the climate is much warmer than what they are adapted to. Humans most likely did have a hand in driving mammoths to extinction, but the climate change alone may have been enough to kill them off. Still, who wouldn’t love to see a real, live mammoth?
