Geology

There are numerous phenomenons that occur in this world, few of them are destructive and powerful while others occur to create life. Our planet earth is thus full of surprises that till this present day it keeps having destructive outburst that may people are suffering from it taking away lives but yet creating new ones by making land or even taking them. I am a geologist whom specializes in both volcanoes and earthquakes and this time I was given a mission to go back in time to study these phenomenon even more so that I may someday save and protect this planet, Earth. I have made myself a part of this journey because I have seen numerous people lose life because the inventions and our knowledge to predict are far more less-intelligent that I thought. I am going to start my journey at the beginning of time where Andrew Wegnar stated that Earth Continent was one a whole one piece instead of the seven continents we have now, and see how the Puzzle theory which he stated maybe have worked and what the consequence of that event was. Since Andrew Wegnar discovered the Continental drift this idea led to the sea floor spreading, found by Harry Hess which we were actually able to see that the land mass was moving a part in the sea. After seeing the wonder of plate tectonics, which is defined as continental drift + sea floor spreading which means that earth surface is covered with plates that move around, I am planning to go see the great eruption of mount saint Helen and see for myself how destructive that event was, and how I can see with my own eyes how powerful the lateral blast was which shocked countless geologists. Finally I will end my journey at the San Francisco Earthquake of 1906 and see how powerful and unexpected that even was. Thus my duty for this travel is to research all this destructive events that occurred during the past and see what we can do in order to lessen these events in order to have less sufferings. I started off my journey at Pangaea where Alfred Wegner proposed the idea of Continental Drift. I learned in lecture that Wegner was the man who thought that Pangaea existed when Earth first was born. Thus, thinking that the combination of centrifugal and gravitational force was the cause of this continental drift. Pangaea was the name Alfred Wegner has named his discovery and had 3 evidence to create this Pangaea. “The word 'Pangaea' means 'all lands' in Greek, accurately defining the way the continents were 200 million years ago before it split up.”(1) These split-up pieces drifted slowly apart and became the way they are today separating that supercontinent that used to be one. There are 3 main theories which I have said before that was constituted by sight and evidence which cannot be ignored, since even after 200millions years this natural evidence has not changed. The first theory was the jigsaw puzzle fit of Africa and South America. By looking at the picture below we are able to see that all 7 continents were once a whole instead of 7 different parts. The second theory are the fossil evidence, this is another significant evidence of this Pangaea theory. By the fossil evidence we were able to see that Pangaea had several similar yet unique fossils in one end of Africa and the other in South America. This means that in order for the same fossil in different parts of the world especially having the huge ocean between the two continents the dinosaur of the extinct creature must had swam over the Atlantic ocean to live; but that is a very unthinkable fact. Thus, by numerous years of research the geologist were able to find fossils which are similar or even identical in parts of the world where it is impossible for them to have met unless they once lived in the same land. “Some examples are the , fossils of the have been found in South Africa, India, Antarctica and Australia which we can see fits perfectly like a puzzle. As we can see that Cynognathus lived in ancient South America and Africa and some of the plants like Glossopteris maybe found in all of these continents since they used to habitat in all South America, Africa, India, Antarctica, and Australia! This fossil being found in all of these continents currently can only mean that once in the ancient times, all of these huge super continents were once a part of each other. (9) The final evidence is a proof that would never move; paleoclimatology. This is the study of ancient climates that may have occurred in the world. There were bits and parts of edge of the continents which were so similar to the point that this evidence were not able to be ignored. “Some Identical fossil ferns have also been found in all southern continents, and also embedded in the same layer sequence as I learned in my lecture suggesting the proximity the southern continents were in millions of years ago that allowed the growing of these ferns in the same climate and soil.”(3) During this discovery the scientist were also able to find that the geological structures of the rocks in South West Africa and South East Brazil were distinctively identical, and the age of the rocks at these two areas was the same. This distinctive rock strata shared by the two land masses suggests that these two areas were once joined together. This is a perfect proof that once when earth was created 4.5 billion years ago that the plates on the surface was one together creating one huge super continent Pangaea. These theories of Wegner were proposed because he discovered the phenomenon of Continental Drift, and this was the first hint to help us volcanologists and seismologist to help lessen the damage of the citizen living in present day Earth because from this discovery we were able to know the plate tectonics and how it causes these pass destruction of the world. My second journey was to the stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. The location of this volcano is 96 miles south of Seattle and 50 miles northeast of Portland, Oregon. “Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century.”(4) But what Mount St. Helen is most famous for is the incident on May 18, 1980, at 8:32 am PDT which was said the most deadly and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles of railways, and 185 miles of highway were destroyed. The massive earthquake measuring 5.0 on the Richter scale caused an eruption, which triggered a massive debris avalanche triggered reducing the elevation of the mountain's summit from 9,677 ft to 8,365 ft and replacing it with a 1 mile wide horseshoe-shaped crater. The earthquake was caused by a sudden surge of magma from the Earth's mantle. The debris avalanche was up to 0.7 cubic miles in volume. After seeing these numbers and the destructive force the Earth can create I was fascinated of how this eruption occurred and how deadly it was. Being back in time I was able to see this happen right before my eyes. It was 8:32 AM when this volcano was waken up with a magnitude 5.1 earthquake for 15-20 seconds creating a huge landslide, it was actually recorded the largest landslide in Earth history. But this was the main problem; the landslide was depressurizing to the volcano’s magma system which triggered that destructive powerful explosion that ripped through the sliding debris. Thus, watching this happen I was able to see the rocks, ash, and the volcanic gas being blasted up and out toward the north. This is what was called a lateral blast since the magma eruption was being rushed out from the side rather than the neck of the volcano which numerous people were horrified by this event. The volcanic landslide is defined as a large scale collapse of volcanic edifices, which are actually common in volcanic process, since volcanoes as well are growing and when they grow they tend to repeated episodes of growth and collapse creating the effect of the deadly lateral blast. “A lateral blast of hot material accelerated to at least 300 miles per hour, then slowed as the rocks and ash fell to the ground and spread away from the volcano; several people escaping from the blast on its western edge were able to keep ahead of the advancing cloud by driving 65 to 100 miles an hour. The lateral blast cloud traveled 17 miles out northward from the volcano and the landslide, lahars, traveled about 14 miles west down the North Fork Toutle River.” (6) “The lateral blast of Mount Saint Helens produced a column of ash and gas that rose more than 15 miles into the sky in only 15 minutes, but there was a scarier surprise awaiting which was that a second eruption column formed as magma erupted explosively from the new crater. Then, beginning just after noon, swift avalanches of hot ash, pumice, and gas poured out of the crater at 50 to 80 miles per hour and spread as far as 5 miles to the north. Based on the eruption rate of these pyroclastic flows, scientists estimate that the eruption reached its peak between 3:00 and 5:00 p.m. Over the course of the day, prevailing winds blew 520 million tons of ash eastward across the United States and caused complete darkness in Spokane, Washington, 250 miles from the volcano.” (6) While watching this all happen I saw the after effect of the explosion. After the eruption I was able to see the parts of the volcanic cloud creating a new volcano rim of the west, south, and east side of the volcano. It seemed like the volcano was rebuilding itself for more destruction, and after a few seconds of the rebuilding I was able to see the next form of force that was being created. One of the geologists explained the incident as the hot rocks and gas quickly melted some of the snow and ice capping the volcano, creating surges of water that eroded and mixed with loose rock debris to form Lahars. Several lahars poured down the volcano into river valleys, ripping trees from their roots and destroying roads and bridges.”(6) Lahars are known to be the greatest destructive force after the volcano and is actually known to be the most greatest reason of the death rate during the volcano. It is just a mudflow in the volcanic terrain but, since it was created by the icecap and the occasional lake being created on top of the vent of the volcano, the water overflow carrying away the loose debris of the side of the volcano creating a avalanche of mud. “The largest and most destructive lahars were formed by water seeping from inside the huge landslide deposit through most of the day. This sustained flow of water eroded material from both the landslide deposit and channel of the North Fork Toutle River. The lahars increased in size as it traveled downstream, destroying bridges and homes and eventually flowing into the Cowlitz River. It reached its maximum size at about midnight in the Cowlitz River about 50 miles downstream from the volcano.” (7) Watching this event I was able to see how destructive these volcanoes can be especially with the strato volcanoes. They are the most active thus most deadly. Mount saint Helen was known to be the most deadly economic shaking explosion and having an earth quake occur at the same time was said to be the equivalent of more than 10,000 tons of exploding TNT rumble through the ground. Some people at the time were saying that they were not able to believe that such beautiful mountain can become so deadly. These words hurt me and made me want to save more people’s lives. My journey ended with the San Francisco earthquake of the 1906. The terrifying rumble of an earthquake shattered the early morning silence of April 18 at 5:15 AM. The quake lasted only a minute but caused the worst natural disaster in the nation's history. Modern analysis estimates it registered 8.25 on the Richter scale. The Richter scale is a magnitude scale that was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. This first started by measuring the seismic waves, which are vibration from the earthquakes that travel through earth, and thus this is measure by an instrument called the seismograph. “The time, locations, and magnitude of an earthquake can be determined from the data recorded by seismograph stations.” (8) Thus to understand the significance of the 8.25 on the Richter scale we need to understand how powerful each number is from 1-10. “On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value.” (8) As we can see 8.25 is 248 times stronger than a 1 and 64 times strength of energy than a 6.3 which is already called a strong earthquake. Three eye witnesses described their experiences: "Of a sudden we had found ourselves staggering and reeling. It was as if the earth was slipping gently from under our feet. Then came the sickening swaying of the earth that threw us flat upon our faces. We struggled in the street. We could not get on our feet. Then it seemed as though my head were split with the roar that crashed into my ears. Big buildings were crumbling as one might crush a biscuit in one's hand. Ahead of me a great cornice crushed a man as if he were a maggot - a laborer in overalls on his way to the Union Iron Works with a dinner pail on his arm." (P. Barrett). But with this earthquake I was able to see that it was not the earthquake that had the most damage but it was the fire ignited from it. One of the people said that “The greatest destruction came from the fires the quake ignited. These ravaged the city for three days before burning themselves out. The maelstrom destroyed 490 city blocks, a total of 25,000 buildings, made over 250,000 homeless and killed between 450 and 700. Damage estimates topped $350,000,000.” (8) But some merits are found from this earthquake. Since the geologist were able to find the rupture point which was northernmost 296 miles (477 kilometers) of the San Andreas fault from northwest of San Juan Bautista to the triple junction at Cape Mendocino and the earthquake being so large actually confounded contemporary geologists with its large, horizontal displacements and great rupture length. We were able to find the fault and actually recognize the significance of it can how it is often set off leading to Led Reid who formulated the elastic-rebound theory of the earthquake source which we use as a principal mode of earthquake cycles today. My journey concludes here. I have researched all I needed seeing and feeling how the earthquake was, and was actually able to experience a volcano. The Pangaea was according to all the research a possible theory starting from the jigsaw, the fossils and the paleoclimatology. It all made sense each and every one of them. Jigsaw meaning puzzle piece actually did fit in with the great example of South America and Africa. The fossils of all the ferns and animals that existed before Pangaea was drifted apart by the continental drift and plate tectonics made sense since all of the animals that lived together then separated live in distinct areas where only if the lands were together could have existed. Some pieces of bones were completely identical to ones in Africa and South America meet. The Rocks formed in the area of the same region were the same as well since Pangaea might have existed. Learning this we learned the significance of the Plate tectonic and how it cause volcanoes and earthquakes. The Saint Helen eruption was the most destructive stratovolcanoe and we were able to see why the lateral blast was so incredibly horrid, and the after effect that can take place. And finally the great 8.25 earthquake and its powerful impact on San Francisco. It was on the Richter scale of 8.25 and this means that it was 248 times stronger than a 1.0 magnitude. The world is full of surprises at every corner. We must research more in order to keep the world safe and happy. Bibliography 1. http://library.thinkquest.org/17701/high/pangaea/ 2. Benton, M.J. Vertebrate Palaeontology. Third edition (Oxford 2005), 25. 3. http://library.thinkquest.org/17701/high/pangaea/ 4. U.S. Geological Survey Geographic Names Information System: Mount Saint Helens 5. http://pubs.usgs.gov/fs/2000/fs036-00/ 6. The mount St. Helens Disaster by Thomas G. Aylesworth & Virginia L. Aylesworth 7. http://earthquake.usgs.gov/learn/topics/richter.php 8. http://www.eyewitnesstohistory.com/sfeq.htm 9. http://www.moorlandschool.co.uk/earth/pangea.htm