Volcanoes, Rocky Mountains, and Tsunamis - Assignment Example

1. Where are volcanoes located in relation to plate tectonic theory? Describe the global pattern of volcanoes. Why are there no active volcanoes in the eastern USA? Active volcanoes are located, mostly, on or very near to sliding plate boundaries. An example would be the “Ring of Fire” volcanoes, located along several plate boundaries. Mount St. Helens is one in this type of location. Other active volcanoes are located along linear chain configurations, in the interior of oceanic plates. The Hawaiian Islands are an example of this location type (Watson, 1997). Globally, we have the North American Plate, the Pacific Place, the Juan de Fuca Plate, the Cocos Pate, the Caribbean Plate, Nazca Plate, the South American Plate, the Antarctic Plate, the Scotia Plate, the Arabian Plate, the African Plate the Eurasian Plate, the Indian-Australian Plate, the Phil. Plate, the Pacific Plate, the Caroune Plate. The North American and Pacific plates are sliding apart and past each other, Pacific moving left and North American moving right. The Juan de Fuca Plate is sliding underneath the North American Plate, and melting (Watson, 1997). There are no active volcanoes in the Eastern US because there are presently no active plate boundaries (no shifting and sliding tension). There is, however, evidence that this was not always the case, and that conditions used to yield volcanic activity, but it was long ago (Watson, 1997). 2. Mt. Rainier is considered the most dangerous volcano in the USA. Why? What are the major hazards that Mt Rainier poses? Mt. Ranier is an active volcano, which has erupted severely, many times over many centuries. It last erupted in 19894-95 and is resting, at the moment, but this temporary situation lulls people into feeling safe when, in fact, they are not safe. Someday it will no doubt erupt again (Driedger & Scott, 2008). This will cause snow and ice to melt, which picks up mud and a lot of destructive force, or large landslides can occur and act in a similar manner. These are called lahars, and they act like a rapidly oncoming, thick wall of concrete. Enough force can carry it all the way to Puget Sound, so many people along the way can be damaged, since there are densely populated areas along the way. Infrastructure would also be destroyed (Driedger & Scott, 2008). The anytime-now probability of lahars from Mt. Ranier activating is actually a very strong and serious risk. About 80,000 people, their homes, businesses, roads, bridges, etc. would be affected. Ashes from the volcano can be dangerous for aircraft visibility and respiratory risk. Utility and transportation systems can be impacted, and it can be rather costly to clean up. One of the most dangerous aspects is that there would likely be no warning, or insufficient warning to prevent mass death and damage (Driedger & Scott, 2008). 3. Choose one of the following mountain ranges and describe its location, elevation, and dimensions. Then give a brief geologic history of the origin of these mountains. Rocky Mountains (southern ranges in CO, NM, and WY) The Southern Rocky Mountains are mostly in Colorado (66%), but also extend into New Mexico (17%) and Wyoming (17%). The entire area covered is 79,008 square miles. It is 542 miles from north to south, and 255 miles from east to west. Its center is located at latitude/longitude 38° 56 N; 106° 34 W. The highest elevation is Mount Elbert, at 14,433 feet (Peakbagger.com, 2012). One of the mountain ranges, within the Southern Rocky Mountains, is the Sangre de Cristo Range. This name is Spanish and it means, “Blood of Christ”. It is 69% in New Mexico and 31% in Colorado. Its highest point is Blanca Point, at 14,345 feet elevation (Peakbagger.com, 2012). Blanca is the Spanish word for “white”, no doubt referring to the snow and ice. The range covers 17,193 square miles, extending 242 miles north to south, 120 miles east to west. Its center is at latitude/longitude 36° 46 N; 105° 17 W (Peakbagger.com, 2012). The basement rocks were formed a billion to 1.8 billion years ago, during the middle Proterozoic. From the late Proterozoic to the middle Paleozoic, limestone, dolostone, sandstone, and shale were deposited and eroded. Beginning in the Pennsylvanian, the Ancestral Rocky Mountains were raised up, including the Sangre de Cristo range. Rapid erosion deposited a lot of sand and gravel near the front of the mountains, and by the end of the Permian, the Ancestral Rocky Mountains had become low hills and flat plains. During the Triassic and Jurassic periods, it remained like this, but with more sediment deposits (Aber, 2012). In the Cretaceous period, it became a shallow sea environment and, by the late Cretaceous period, the structure of the Rocky Mountains began to be raised and the edges were defined by major thrust faults, as in the Sangre de Cristo Mountains. Crustal compression changed to crustal extension, in the mid-Tertiary time, and rifting occurred west of the Sangre de Cristo. During the Ogliocene and Miocene periods, the rifting resulted in lots of volcanic activity, which eventually slowed down in the Quaternary period. From the Pleocene time, massive uplift and erosion occurred. In the Ice Age of the Pleistocene Epoch, glaciers in the Sangre de Cristo carved fascinating Alpine landforms (Aber, 2012). 4. Define "tsunami". What is the derivation of the term? What causes tsunamis? How fast do they move; how high can they get? Can we monitor and forecast tsunamis? Tsunami means, in Japanese, a “harbor wave” (National Weather Service, 2009). A tsunami is usually a series of waves that send huge walls of water, sometimes as much as 100 feet tall, onto the land. They are very powerful and very destructive. About 80% of tsunamis take place within the Pacific Ocean’s “Ring of Fire” (National Geographic, 2012). What usually causes a tsunami is when there is a shifting of the tectonic plates on a plate boundary and part of the ocean floor either rises or falls suddenly, displacing water and triggering the waves. Underwater landslides and volcanic eruptions can also initiate a tsunami. More rarely, a tsunami can be caused by a huge meteorite crashing into the sea (National Geographic, 2012). Tsunamis can travel at the same speed as a jet aircraft, up to 500 miles per hour and take less than a day to cross the Pacific Ocean. As they come to the shore, the top of the wave is moving much faster than the bottom of the wave, and this creates a vacuum effect that sucks the water at the coast out to the sea. Then, in minutes, the wave arrives, often followed by a series of waves, although sometimes it doesn’t arrive in waves at all, but in a rapidly moving tidal surge (National Geographic, 2012). A partnership of 26 countries has cooperated on the Pacific Tsunami Warning System, in Hawaii. Gauges to measure the water level and seismic activity are part of the warning system. Countries in all coastal parts of the world are setting up systems to monitor the sea and give warning of an impending tsunami, sounding sirens when the risk appears to be there (National Geographic, 2012). Sometimes the warning is given, but the tsunami that was expected never arrives, as happened in Indonesia this month, where the waves were only 17 centimeters high. Still, warnings should be heeded because a tsunami is the worst kind of a disaster! References Aber, J. A. (2012). Rocky Mountain Geology South-Central Colorado. Retrieved from Emporia.edu: http://academic.emporia.edu/aberjame/field/rocky_mt/rocky.htm Driedger, C. L., & Scott, W. E. (2008). Mount Ranier - Living Safely With a Volcano in Your Backyard. Retrieved from geology.com: http://geology.com/usgs/rainier/ National Geographic. (2012). Tsunamis: Killer Waves. Retrieved from National Geographic: http://environment.nationalgeographic.com/environment/natural-disasters/tsunami-profile/ National Weather Service. (2009, November 25). Pacific Tsunami Warning Center. Retrieved from NOAAs National Weather Service: http://ptwc.weather.gov/faq.php#2 Peakbagger.com. (2012). Sangre de Cristo Range. Retrieved from Peakbagger.com: http://www.peakbagger.com/range.aspx?rid=1468 Peakbagger.com. (2012). Southern Rocky Mountains. Retrieved from Peakbagger.com: http://www.peakbagger.com/range.asps?nd=146 Watson, J. (1997, January 31). Plate Tectonics Theory. Retrieved from USGS: http://pubs.usgs.gov/gip/volc/tectonics.html Read More