The Relationship between Earthquakes, Volcanoes, and the Science behind their Occurrence - Report Example

The relationship between earthquakes, volcanoes, and the science behind their occurrence Executive summary This paper has discussed the relationship between earthquakes and volcanic activities. The scientific explanation for the occurrence of these phenomena has also been discussed. First a brief introduction of earthquakes and volcanoes was outlined. This was followed by a short brief on the theory of plate tectonics which try to explain the occurrence of the earthquakes and volcanic activities. The relationship between the two phenomena was then discussed followed by scientific facts about the two. From the discussion it is apparent that earthquakes and volcanoes have been known to be prevalent in certain regions of the world. Areas most hit by earthquakes also experience some volcanic activities. Thus there exists some relationship between earthquakes and volcanic activities given that the location of these two natural disasters is mapped in similar regions of the world. The violence of eruption of a volcano is usually dependent on the mix of rocks, water and gases contained in the magma. Prediction of the occurrence of volcanoes is somehow easier to predict since they are accompanied with many prior warning signs. Earthquakes results from drifting tectonic plates colliding or moving away from one another. The prediction of the possible occurrence of earthquake is usually very difficult. However, scientists are able to make prediction of possible occurrence of earthquakes by studying fault line of different tectonic plates. The study of fault system by seismologists and geologists has been instrumental to the understanding of earthquakes. Table of Contents Introduction 4 Earthquakes 4 Volcanoes 5 Theory of plate tectonics 5 Relationship between volcanoes and earthquakes 6 Volcanic earthquakes 7 The science behind the occurrence of volcanoes 8 The science behind the occurrence of earthquakes 9 Conclusion 10 References 11 Introduction Earthquakes and volcanoes have been known to be prevalent in certain regions of the world. areas most hit by earthquakes also experience some volcanic activities. Thus there exists some relationship between earthquakes and volcanic activities given that the location of these two natural disasters is mapped in similar regions of the world. This paper will discuss the relationship between earthquakes and volcanic activities. The scientific explanation for the occurrence of these phenomena will also be discussed. First a brief introduction of earthquakes and volcanoes is outlined. This is followed by short brief on the theory of plate tectonics which try to explain the occurrence of the earthquakes and volcanic activities. The relationship between the two phenomena is then discussed followed by scientific facts about the two. Earthquakes The trembling or the shaking of the crust of the earth which results from abrupt release of energy is referred to as earthquake. These are usually seismic waves which are generated by either manmade events or natural phenomena. Earthquakes are often caused by abrupt release of pressures which have been accumulating over a period of time. The measurement of the seismic waves generated is done by the help of seismometer. This helps in indicating the size or intensity of the earthquake. The moment magnitude scale (MMS) represents the earthquake size. In most cases a magnitude of 3 or below 3 is usually undetectable. On the other hand a magnitude that is equal to or greater than seven results in maximum damage to property and even life. The focus or the hypocenter is underground point where the earthquake originates. The point on the surface of the earth which is exactly above the focus is referred to as epicenter. Volcanoes The openings in the crust of the earth which are accompanied by ejection of molten rock and hot gases on the earth surface are referred to as volcanoes. The extrusion of magma during volcanic eruptions often results in the formation of mountains or mountain like landscapes once the ejected molten material cools down. Volcanoes can take place in any part of the earth surface, that is, on land or in oceans and seas. The activeness of a particular volcano determines its classification with eruptive ones being classified as active, presently not active volcanoes being classified as dormant volcanoes while those that are not eruptive being classified as extinct types. Volcanoes are further classified into six different types which are dependent on the mode of ejection and other characteristics. These are: shield, submarine, cinder, stratovolcano, subglacial and supervolcano. Theory of plate tectonics According to this theory, there are two types of tectonic plates, continental and oceanic. These plates are usually in constant movements along their boundaries which vary in speed. Collision of the moving plates results in the creation of landforms such as coastal volcanoes, mountain chains and island arcs. Tectonic plates moving apart results in production of new ocean floor as the magma originating from the mantle rises up through volcanoes and deposits new rocks along the boundaries of the plate. In cases where plates slide over one another no destruction or creation of new landforms take place. According to this theory, the movement of the plates results in vibrations which causes earthquakes. Relationship between volcanoes and earthquakes The relationship between earthquakes and volcanoes is depicted by the maps showing the locations where these two phenomena occur on maps. A comparison of maps showing locations where the volcanoes and earthquakes occur evidently shows a match one another. The main theory behind the occurrence of these two natural calamities lies in plate tectonics. It is believed that the earth is made of irregularly shaped plates of varying sizes which move constantly at different speeds. Thus the plates are constantly drifting over the mantle layer of the earth. The movement results in the generation of magma along the boundaries of these plates. Volcanoes and earthquakes are often witnessed at the boundaries of these plates. The collision, separation or sliding of the plates on one another results in the generation and accumulation of strain (pressure) which upon release causes earthquakes. Plate collisions usually results in the manifestation of the strongest earthquakes. On the other hand, when plates are moving apart from one another, slowest earthquakes are observed. Similar to occurrence of earthquakes, volcanic activities or volcanism is observed when plates move apart (diverge) or when plates move towards one another (converge). Such plate movements results in the rise of magma that is present in the boundaries of the plates to the surface of the earth. This leads to volcanic eruptions. Volcanism resulting from plates drifting apart causes long volcanic rifts while volcanism resulting from plates drifting towards one another results in individual volcanic eruptions. Volcanoes and earthquakes can also occur within a plate. This is usually referred to as intraplate volcanoes and intraplate earthquakes respectively. About ten percent of all earthquakes are estimated to be in intraplate earthquakes. Volcanic earthquakes These are earthquakes related to volcanic activities. There are two types of volcanic earthquakes, volcano tectonic earthquakes and long period earthquakes. Volcano tectonic earthquakes results from stress changes in solid rock as a product of injection or withdrawal of magma. Such earthquakes can result in subsiding and production of large ground cracks. These earthquakes may occur when the rock moves to fill spaces where magma is no longer present. Occurrence of volcano tectonic earthquake is not an indication that the volcano will be erupting but it is an indication that it can occur any time. Long period earthquakes occur when there is injection of magma into the surrounding rock. These quakes occur when there are pressures changes occur during the transportation of magma. When these injections of magma are sustained many earthquakes occur. Such activity is an indication that a volcano is about to erupt. Seismographs are used by scientists to record the signal (volcanic tremor) from these earthquakes. Thus exhibition of volcanic tremor by earthquakes is a warning of impending eruption hence people ought to be evacuated from such areas. For instance, volcanic tremor signal was successfully used to predict the 1980 eruptions in mount St. Helens and the 1991 eruption of Pinatubo. The science behind the occurrence of volcanoes The explosion of volcanoes differs in terms of violence. Some volcanoes are usually gently and the lava is usually seen to ooze out of the vents. The violence of eruption of a volcano is usually dependent on the mix of rocks, water and gases contained in the magma. Prediction of the occurrence of volcanoes is somehow easier to predict since they are accompanied with many prior warning signs. It is a common believe among scientists that over 3,000 volcanoes have erupted in the last 50 years. It is estimated that there are between 50 and 70 active volcanoes in the world today which exists in various states of activities. Some of these volcanic activities spew lava slowly while others are violent ones. In some cases, initial explosion consisting of gases, steam and magma are followed by volcanic spew called pyroclastic flows. Larger volcanoes also experience pyroclastic surges which consist of hot ash, rock fragments and gas. The temperatures of these pyroclastic surges can reach a high of 1500 degrees and can move at astonishing speed of 150 miles per hour. Surges are more energetic than flows and are mainly composed of rock fragments and superheated gas. The surges move faster than flows but devastating effects of both are similar. More often flows are followed by lahars. This consist of water, rock, sand and mad which flow down valleys leading away from volcanoes. The movement of lahars is similar to movement of rivers and sometimes consists of enough force that can uproot trees, rip bridges away from their support and tear houses from their foundation. Ash cloud is the final fallout from an eruption. Ash can be projected over 12 miles above the opening by a volcano in as little as ten minutes. Scientific equipments can help in predicting the occurrence of a volcano. This is done by checking the heaving of the land. This indicates the pressure that is being build in the magma chamber. In addition, prediction of the occurrence of volcano can be done by recording the frequency and intensity of earthquakes around the volcano. Increased frequency and the centering of earthquakes on the volcano presents ripe conditions for the occurrence of volcanic eruption. This explains the intrinsic linkage between earthquakes and volcanic eruptions. Even though powerful earthquakes do not result from occurrence of a volcano, all volcanic eruptions results in occurrence of a series of smaller earthquakes. The science behind the occurrence of earthquakes As mentioned earlier, earthquakes results from drifting tectonic plates colliding or moving away from one another. The prediction of the possible occurrence of earthquake is usually very difficult. However, scientists are able to make prediction of possible occurrence of earthquakes by studying fault line of different tectonic plates. The study of fault system by seismologists and geologists has been instrumental to the understanding of earthquakes. By studying the geologic history of such fault lines and determining the normal rate of slippage between tectonic plates, scientists are able to establish the behavior pattern across hundred of years. Using such information, scientists can determine when the quake is due in a given area by lack of recent slippage of the tectonic plates. In addition, by studying this fault system, scientists are capable of identifying seismic gaps which are areas of the fault line that sustain the greatest strain. Scientists pay a close attention to precursors of earthquakes such as seismic silence which is an indication of absence of slippage. The also examine any recent lack of occurrence of a major quake within a past span where major earthquakes had previously followed a regular pattern. Such key precursors enable scientists to predict with reasonable accuracy the probability of the occurrence of an earthquake in a specified region. In spite this; scientists cannot predict a specific date when the earthquake will likely take place. They can only make a prediction of the probability of the quake to take place within a broad time frame of a decade. Scientists also estimate the likelihood of occurrence of an earthquake by studying how fast pressure accumulates. When the strain in the rocks caused by plate movements builds to a critical level, rocks will suddenly break up and slip to a new position. Scientist measure the accumulation of strain along fault segment on yearly basis. This is compared to how much time has elapsed since the last earthquake along the segment and how much pressure was released in the last quake. This data is then used by scientists to calculate the required time for the strain to build to the level those results in occurrence of earthquake. Research in the known and unknown precursors of earthquakes has not yielded consistent results. Conclusion The trembling or the shaking of the crust of the earth which results from abrupt release of energy is referred to as earthquake. The openings in the crust of the earth which are accompanied by ejection of molten rock and hot gases on the earth surface are referred to as volcanoes. Earthquakes and volcanoes have been known to be prevalent in certain regions of the world. Areas most hit by earthquakes also experience some volcanic activities. Thus there exists some relationship between earthquakes and volcanic activities given that the location of these two natural disasters is mapped in similar regions of the world. The violence of eruption of a volcano is usually dependent on the mix of rocks, water and gases contained in the magma. Prediction of the occurrence of volcanoes is somehow easier to predict since they are accompanied with many prior warning signs. Earthquakes results from drifting tectonic plates colliding or moving away from one another. The prediction of the possible occurrence of earthquake is usually very difficult. However, scientists are able to make prediction of possible occurrence of earthquakes by studying fault line of different tectonic plates. The study of fault system by seismologists and geologists has been instrumental to the understanding of earthquakes. References Read More