 Let's go over a little bit of information about using the USGS Earthquake website that my online lab students are going to be using. In particular, I want to give you an introduction to the default screen and then how you can change to different views. So when you first open up the link that I have on Blackboard, it should take you to something that looks like this. It should show the entire US and it should have the one day magnitude 2.5 plus US. Now this first piece of information over here is the time span. Then it tells us the magnitude range which is either all magnitudes or magnitudes over 2.5 which is what the 2.5 plus means or some other information over here. And then it shows us what the span we're looking at and right now we're looking at just the US. The line underneath that tells us how many earthquakes total and how many are in view on the screen. So right now there's 40 earthquakes total but only 17 of them are being shown on the screen. The rest of the information here on this left column deals with individual earthquakes. If you click on a particular earthquake and I'm just picking the top one here, it will bring up a little bit more information in a pop-up box down here and it will also highlight it on the map in blue so you can see which earthquake it's dealing with. Now the first piece of information here is the magnitude which is 4.0. Down here it has M4.0 to let you know that that's a magnitude 4.0 earthquake. It then gives our location. Typically they don't happen in a town so it will always tell you how far it is from the closest town. In this case it's 35 kilometers west of Mentone, Texas. Underneath that it's got information about when the earthquake happened which is also over here. It gives the date with the year, month, and day and then it gives the time in UTC time system which is what we studied in last week's lab. It also gives us the depth of the earthquake which you can see here next to the information or here on the bottom. So that's how far down underground the earthquake was. The pop-up box will also give you the more precise latitude and longitude coordinates instead of just the distance from the closest town. And you can do that for any one of the earthquakes and you can scroll down to see the entire list of earthquakes that are listed here. Now you can also zoom in and out to see more clearly. So if I wanted to zoom in you can either use your little scroll bar or you can use these little plus and minuses. So there was two particular earthquakes here and because I've scrolled in there's only two of the 40 earthquakes being shown on the map. But if I want to actually see the whole U.S. I want to go back to zoom the whole U.S. in order to see all of them that were in the U.S. If I needed to zoom out to see the entire world now it shows me that I've got pretty much all the earthquakes on the map. Now be aware that this is a real time information system so you'll see pop-ups about earthquakes updated and you may actually have a new earthquake pop up on the top of your list because the top here is the most recent earthquake and the bottom is going to be the oldest earthquake. So if you do this over an extended period of time the information may actually change as you're working through the lab. So try and do this part of the lab in one sitting. Now you'll also notice over here that the dots are different sizes. If I have a very small dot it's a lower magnitude one. As I get into the larger dots they're going to be the larger magnitude earthquakes. So the stronger the earthquake is the larger the size of the dots shown on the map is. Now when I ask you about clusters in some areas you may end up having multiple. So for example on this particular day it'll be different on the day you do it. There happens to be a cluster here right off of Puerto Rico when there was a lot of earthquakes that happened all in the same area. So that's a cluster of earthquakes for that particular day. Now besides zooming in and out there are some other controls that we can use. If you come up here there's a settings and that's right above where the zoom is. And it looks like a little gear or some students say it looks like a flower but it's a gear. It brings up the settings and here you can actually change it so that you can look at all magnitudes not just the ones above 2.5 or you can change the date range. So in your lab you're going to actually be using several one of these and answering questions about the differences. So one all magnitudes or seven days 2.5 plus or the most significant largest earthquakes over the last month etc. If you want to close this off to get a better view you just click this again and if you click the settings it opens it and closes that so you can see what's happening here on the earthquakes. And again you can zoom out to see the entire world or zoom in just to see a particular area of the country. If you have any questions about the controls please feel free to use the blackboard forum or send messages to your instructors.