Earthquakes & flooding

I have decided to start this post off by talking about some things that happen in Santiago, Chile, but that I have never experienced in North Dakota. Living in a different country has made me think about some of the things we do in our part of the world, and here are a few things I have noticed:

◊ Earthquakes – About a week ago I was awoken in the very early hours of the morning by feeling a little unstable lying in my bed because there was a 5.5 magnitude earthquake near Santiago. My first earthquake in Chile! It was definitely a weird sensation that I didn’t connect to being an earthquake right away.

◊ Day off school due to rain – Last weekend it rained for 3 days straight. Very unusual in
Santiago, I’ve been told. The city gets all of its water from the River Mapocho, and because the rain flows down the Andes into the river, it flooded. Due to this, the city cut off the water supply to about half the city for 24 hours over the weekend. Luckily I still had water, but the university was closed that Monday.

◊ Kissing everyone hello & goodbye – In the US in general if your friend or classmate walks in the door you say “Hey” or “Hi”, etc. Here, when you get to school/work you literally walk around to everyone to greet them with a kiss on the cheek. It took me a couple days to get used to being so close to everyone, even people who I don’t know at all. The men shake hands with each other, but women always get a kiss.

◊ Fruit-flavored everything – There are so many exotic fruits in South America on top of the standard raspberry, strawberry, apples, & oranges. Restaurants always have some fresh fruit juices, the kind that you won’t find in the Midwest anywhere. My favorites are maracuya and guayaba. The ice cream is also really fresh and natural, and even the vanilla flavor tastes amazing. You can’t find crazy flavors like moose tracks, but they make up for it with fruit flavors I have never even heard of.

Research stuff

sem1.jpg
SEM computer – four cameras at once! The white mineral in the upper left is a pyrite grain.

This past week I been reading about how to model fluid flow through a system, and read a paper about how these two Icelandic geologists used PHREEQC to create a model for fluid interaction and mineral precipitation for a geothermal system in Iceland. PHREEQC is a computer program used to model different chemical reactions, speciation, transport, and much more. You use it by entering your water, steam, or rock elemental composition, adding the temperature, pH, redox parameters, pressure, and any other parameters that are known. Then you run simulations to predict the speciation and conditions after mixing the solution with another solution, for example. I have some experience working with PHREEQC from my time in geochemistry at NDSU. I have been re-learning the syntax and keywords of the program and reading through examples in the PHREEQC manual and am starting to formulate a plan for my own simulations.

This morning I was trained in on the SEM at UChile! The SEM is a Scanning Electron Microscope that shoots a very focused beam of electrons at your sample in order to take really detailed pictures of it at very high magnification. The electrons that interact with your sample cause many different types of signals to be produced, so depending on what kind of image you’re looking for is the type of signal you’ll choose. The SEM can also perform chemical analysis on particular spots of your sample, as part of the information from one of the types of electron interactions. This is used to determine the chemical composition and subsequently the mineral formula at that spot. I am taking pictures of thin sections from a Tolhuaca geothermal core to put in a paper that is currently being written. The grad student I’m taking the photos for already has the spots on each sample picked out, so my job will just be to find the tiny pyrite grains and take pictures of them on the SEM. I will also be annotating the pictures with names of minerals associated with the pyrite in photoshop.