Earthquakes: How they happen and what to expect.
What is an Earthquake? Have you ever wondered how it starts and what causes it? Many people spend everyday studying this to find answers. In theory scientists do know that an earthquake is the shaking of the ground caused by sudden release of energy inside the earth's crust. This is also known to scientists as the breaking and moving of tectonic plates along a fault line, which than creates seismic waves at the epicenter. The earthquake has three different types of shocks that are usally felt. First one being a foreshock which happens in the same place as the larger earthquake, but scientists can not tell for sure if the quake felt is a foreshock until the larger quake happens. The
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Primary effects are usually a result of the ground shaking causing buildings to collaspe. This than results in the secondary effects which are usually tsunamis, fires due to gas lines rupturing, landslides and other catastophic events. Human life is impacted greatly by all of these as they leave us without homes and missing family members that might be trapped under rumble and debris. As if that wasn't bad enough earthquakes tend to casue tsunamis which destroy absolutely everything in their path. Nothing will stand a chance in the path of a tsunami as it's huge wave of destruction takes its course. Another disater would be a landslide which is often more desturctive than the earthquake itself. In Alaska, Turnagain Heights, an entire residential area was destroyed by a shock induced landslide. Many seimologists believe that earthquakes do not kill people, buildings do. They feel that during an earthquake the destruction of buildings and man made structures crashing down cause most of the deaths. Another devistating aftermath of an earthquake is the fires due to broken gas lines and electrical lines. During an earthquake gas is set free and the smallest spark will cause the biggest inferno. An example of this would be the great earthquake of 1906 in San Fransisco which caused 90% fire
Earthquakes, by Webster’s dictionary definition, are, “a shaking or trembling of the earth that is volcanic or tectonic in origin.” World Book Encyclopedia reports scientists believe that more than 8,000 earthquakes occur each day without causing damage. A little more than 1,000 each year are strong enough to be felt. Earthquakes occur in the general sense, anywhere on land. Other earthquakes go by different names, such as volcanic eruptions and tsunamis, large tidal wave storms that occur underwater, primarily in the Pacific Ocean.
Earthquakes play a major role into understanding the composition and materials that exist within the Earth (Merali and Skinner, 2009, p.252). Earthquakes are the main source of insight into the inner workings of the earth, due to the nature of the seismic waves they produce. P and S waves are reflected and refracted at different boundaries within the earth, and this enables seismologists to make inferences about the internal composition and structural of planet Earth. (Merali and Skinner, 2009, p.252).
Earthquakes are frequent but most of the time aren’t very big on the Richter Scale. Statistics and research show that there are earthquakes happening constantly, but most of the time are impossible to feel unless they are above a 3 on the Richter Scale (see source7).
The 1906 San Francisco earthquake was one of the largest earthquakes in the United States. Even though it only lasted less than a minute, the damages and aftermath of the earthquake were disastrous. These damages were not just from the earthquake, but also from other hazards that occurred because of it. It also had a huge effect on the people living in San Francisco. Many people, the government, and other countries helped the city of San Francisco with relief goods like food and clothing. The city used up their resources in order to rebuild the city and spent a lot of money. This earthquake also started a scientific revolution about earthquakes and its effects.
Earthquakes are best described as a shaking or vibration of the ground caused by breaking of rock. Sometimes they are very strong and other times you would hardly notice them. This shaking occurs when stress that builds up in the crust is suddenly released as the crust breaks free and/or slides against the other pieces of crust. Earthquakes may also be thought of as the breaking of a popsicle stick by applying pressure to both ends at the same time. Should you try this experiment , you will feel the pressure build up as you apply more force until the stick snaps. When the stick snaps you will feel an instant of pain at your fingers as the stress reduces and energy waves move throughout the stick. When the earth's crust is placed under similar types of stress, binding as the stress builds, it will also snap and release the energy into the surrounding rocks, 'ooch'. Thinking about earthquakes will become more clear if you try another experiment.
The San Francisco earthquake that took place in 1906 is fairly well-known because of its damage and intensity that would affect many lives. The online exhibit of The 1906 San Francisco Earthquake and Fire shows how much was lost during this natural disaster, and how the city was before. Many would wonder what is the purpose of documenting how it was before, and after the earthquake, but the fact that no one was expecting one so big impacted countless lives. Also, at the time San Francisco was becoming the most popular city, therefore it would appear in the headlines how a well-known place that most people loved would become damaged (The Bancroft Library, 2006). Overall, this virtual field trip shows the cause and effect of the earthquake that would change San Francisco in numerous ways.
From studying the science behind the San Francisco earthquake, scientists have made a number of important discoveries involving how earthquakes function. At 5:12 on a fateful April morning in 1906, the mammoth Pacific and North American plates sheared each other at an incredible twenty-one feet along the San Andreas fault, surpassing the annual average of two inches (“San Francisco Earthquake of 1906”) (“The Great 1906 Earthquake and Fires”). A few seconds later, the destructive earthquake occurred. The ground shifted at almost five feet per second, and the shaking could be felt all the way from southern Oregon to southern Los Angeles to central Nevada (“Quick”) (“The Great 1906 San Francisco Earthquake”). In fact, the earthquake could be registered in a seismograph on Capetown, South Africa, an astounding 10,236 miles away...
Tsunamis caused by the Earthquake leads to flooding along the coastal environment. This damages any homes. Flooding caused new lakes or sag ponds on the land. Increasing groundwater flow from springs and displacing stream channel. ("Flood Consequences")
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
The effects caused by earthquakes are devastating. They cause loss of human life and have effects on infrastructure and economy. Earthquakes can happen at any time anywhere. In January 12, 2010 an earthquake of a magnitude of 7.0 hit the nation of Haiti. An estimation of 316,000 people were killed, and more than 1.3 million Haitians were left homeless (Earthquake Information for 2010). Haiti was in a terrified chaos. After the earthquake, families were separated because many of the members were killed. Homes, schools, and hospitals were demolished. People lost their most valuable belongings. It will take time for the country to recover from this terrible disaster. The long damages are economic issues, health-state, and environmental issues that effect in the beautiful island of Haiti.
The effects of the Alaskan earthquake, unfortunately are what secured its place as one of the deadliest earthquakes ever recorded. From property damages, to the massive death toll, this earthquake devastated the lives of the people of anchorage, and multiple other towns within its destructive range. Unfortunately, the effects of an earthquake do not strictly come as one configuration. The disaster comes in the form of violent shaking of the earth, tsunamis, landslides and other incidents.
As the tectonic plates slide over each other, they cause earthquakes. Earthquakes produce various damaging effects, this includes damage to structures of buildings, bridges and other standing formations which then result in injuries and people getting killed, wildlife getting disrupted as well as humans. An earthquake can affect the earth as it’s easier to let the lava come out of the earth. Tsunamis- Can cause financial problems such as home loss, job loss which will then result in being homeless, loss of crops and food supplies which causes a lot of harm to us ‘humans’. A tsunami is a series of waves that send surges of water that can travel thousands of miles.
Earthquakes are vibrations felt at the surface of the earth which are caused by disturbances of the energy in the earth's interior. These vibrations are known as seismic waves. (Skinner Robinson McVerry 1) There are different type sof seisimc waves such as Primary (P) waves, whcih travel the fastest, Secondary (S) waves which cause the earth to vibrate vertically, Surface (L) waves. P and S waves are "affected by changes in the density and the rigidity of the materials through which they pass." (Columbia Encyclopedia) Earthquakes vary in their intensity and duration. Often times they are strong enough to cause massive destriction. Tall buildings often suffer as a result of these natural disasters. In recent years this has become a larger and larger threat with both the number of large buildings, and their number of occupants increasing. In an effort to try to minimize the damage caused by earthquakes many some engineers focus primarily on designing and constructing earthquake resistant buildings. Earthquake engineers have gathered much of their information from analyzing past earthquakes, and learning which buildings can and can't withstand the tremors. The goals of these engineers is to design buildings that can withstand moderate earthquakes and obtain minimal damage, and that the buildings will not collapse lowering the probability of human deaths.
Earthquakes belong to the class of most disastrous natural hazards. They result in unexpected and tremendous earth movements. These movements results from dissemination of an enormous amount of intense energy in form of seismic waves which are detected by use of seismograms. The impact of earthquakes leaves behind several landmarks including: destruction of property, extensive disruption of services like sewer and water lines, loss of life, and causes instability in both economic and social components of the affected nation (Webcache 2).