Question 3: Volcanism & Tectonic AnalysisCOLLAPSEYou often hear about or read in the media about an earthquake or volcanic eruption happening somewhere. If you know the tectonic setting you should be able to make a good educated guess as to what is going on!————————————————For a volcanic eruption if you know (or look up using a map with plate boundaries) the tectonic situation there you should be able to deduce things like:* what type of volcano it is (shield ridgecrest composite cone)* what is the range of magma chemistry that built the volcano (and that could be erupting now)* the source of that magma* what the likely hazards are from that volcano (this is a strong motivation to understand all the previous points!)In the post below you’ll be given a real volcano or a volcanic region. Then you’ll be given some specific questions about it that will involve you determining the tectonics involved with creating the volcano and the details related to what you think are the most likely range of possibilities for a volcano in that region.————————————————This shouldn’t take a long time to do. Once you figure out the tectonic setting then the rest really just drops out of the pdf slides. You don’t need to do any research at all. You can if you like but you can find the location of the volcano (on the web) and then just look at the maps of plate motions/speeds in the Plate Tectonic pdf files to help you deduce the tectonic setting.The important part then is to clearly explain why you made your statements!Question: Mount St. HelensQuestion: Mount St. HelensCOLLAPSEView Original Post Parent PostFor reading week you decide to travel to the Cascades area of Washington State (USA) to check out the skiing south of the border. You spend a couple of days on Mount Baker then head south to Olympia to visit a friend.Your friend works for the USGS and offers to let you join a trip to service instruments monitoring the Mount St Helens volcano so you jump at the chance! You know that the volcano was erupting off and on since 1980 and you’ve never been close to a really active volcano… Later hanging out back in Vancouver you tell your friends about your trip. They’ve heard of Mount St Helens but don’t know much more about it. You answer their questions…1) What type of volcanoes (shield ridgecrest composite cone) are the ones in that area (including Mount St Helens)? Explain why by describing what controls the type of volcano shape/structure.2) What type of tectonics or plume (hotspot) formed Mount St Helens?3) From what you know about the volcanic and crustal setting there what would you expect to be the range of magma chemistry that has built the volcano? What type of magma chemistry do you think is most likely to be erupted next? Why? [Detailed chemistry isn’t necessary make sure you bring it back to the basics with the ultramafic – mafic – intermediate – felsic categories. Remember you are explaining to people there that likely don’t have much background all]4) Where did the magma that erupts at Mount St Helens likely form in the mantle and/or crust? Why? [perhaps more than one location is possible? If you struggle with this question make sure you understand where and why melting happens in each tectonic or plume setting]5) What are the likely hazards from the local volcanoes here? Explain why each hazard is possible there.
