San Francisco Earthquake And The 1964 Alaska Earthquake

The earthquake was located on the San Andreas fault which is a seismic zone between two of the earth’s tectonic plates. Seismic events which occur is caused as a result of the earth’s tectonic plates moving against each other and this can cause huge earthquakes and volcanoes (“Young”). The transform boundary passes through California and this is where the Pacific and North American plates move past each other without colliding. The event in which this occurred was the San Andreas fault (“Young”). When the plates move past each other and the resistance builds up, this causes an earthquake like the 1906 San Francisco earthquake. This earthquake caused a separation and displacement in the landscape which was seen over several kilometers

The earthquake was felt from southern Oregon to south of Los Angeles and inland as far as central Nevada, an area of approximately 200,000 square miles. The ground motion caused by the earthquake source is recorded by instruments called seismographs. The zigzag trace made by a seismograph, called a "seismogram," reflects the changing amplitude and frequency content of the ground shaking beneath the instrument (usgs.gov). Using seismograms, scientists can determine the time, the epicenter, the depth, and the type of faulting of an earthquake as well as estimate how much energy was released by it.

California, and thus San Francisco, lies on the San Andres fault. The earthquake was caused when this fault suddenly shifted, with the rupture spreading for a total of 476 kilometres in northward and southward direction. “This fault is a continental transform fault, which forms part of the tectonic boundary between the North American Plate and the Pacific Plate.” (1906 Earthquake: How long was the 1906 Crack? USGS Earthquake Hazards Program – Northern California, Accessed September 3, 2006). 1 The distance of the fault is of about 1300 kilometres, which runs the length of California from Cape Mendocino in the north to the Salton Sea in the south. Geologists have estimated that the fault moved as quickly as 2.74 kilometres per second. The San Andreas Fault, the source of this disaster, lies ten miles or deeper, at the meeting point of two tectonic plates, the Pacific and the North American. “The right-lateral strike-slip fault is characterized by mainly lateral motion in a dextral sense, where the western plate (Pacific plate) moves northward relative to the eastern plate (North American

Imagine yourself home doing a couple of sets of jumping jacks but then you feel weary so you stop for a water break. You notice that you kept on bouncing but it wasn’t your body moving it was the Earth that was shaking you, an earthquake occured. Earthquakes happen when the underground continental plates move. Earthquakes can affect the Earth, people, and property. To begin with, when an earthquake happens something on Earth is most likely to change.

Earthquakes are caused when two blocks of earth suddenly slip past one another. The surface where the two blocks slip is called the fault. The earthquake starts below the earth’s surface at the hypocenter, and the location above the hypocenter is called the epicenter. Earthquakes can have foreshocks which is a smaller earthquake that happens before the larger quake. Earthquake can also

Professor H.F. Reid introduced observations provided the basis for the landmark "theory of elastic rebound .This theory describes how the earth's crust gradually and elastically distorts with accumulating plate motion until it is suddenly returned to its undistorted state by rapid slip along a fault, releasing the years of accumulated strain and, in the process, generating seismic waves that produce shaking. Before 1906 and Reid's theory, this basic mechanical concept of earthquakes -- that the faulting causes the earthquake and that the earthquake does not cause the faulting -- was not well recognized as a universal principle applicable to the San Andreas

The energy coming from this rupture is called seismic waves. These waves fan out in every direction from the earthquakes epicenter and results in intense shaking. Once this shaking reaches the earth’s surface, everything from the ground up will also proceed to shake (Wald 2012). In order to measure the size of an earthquake, scientists use seismographs. Seismographs consist of a base, a spring, pen, rotating drum, and a heavy weight. The base is placed in the ground while the weight hangs above. When an earthquake occurs the spring absorbs the shaking and the weight and pen, which remain motionless, record the difference between the shaking and motionless part of the seismograph. Seismograph recordings consist of short and long wavy lines, with long lines indicating a larger earthquake (Wald 2012). These recordings are then

In 1906 the most deadliest earthquake in the world shook the grounds of San Francisco California The earthquake was caused by a slip that of the San Andreas fault, over a segment about 275 miles long, and shock waves could be felt from southern Oregon down to Los The epicenter of this earthquake has moved around in the past 100 years, as advances in seismology has been made At first it was thought to have been Marin County but, most recently, in the Pacific Ocean about two miles west of San Francisco. The San Andreas Fault is on the boundary between the Pacific plate and the North American plate. During the earthquake, the ground west tended to move northward in the most extreme instance a 21 foot shift upward was measured.

There are many earth hazards everywhere on earth which both humans and nature share a role, natural hazards such as volcanoes, floods, forest fires, and avalanches, and purely of human origin like the chemical leak, oil spills, and human made earthquake. But one of nature's most dangerous hazard that we have to live with in California must are earthquakes. A earthquake is when two tectonic plates slowly slip past each other and get stuck which creates friction. The point where the two blocks slip is called the fault or fault plane. When the earthquakes start is at the hypocenter, and the point above the hypocenter is called the epicenter. After a earthquake, there are aftershocks that are smaller earthquakes, some aftershocks can be as large

Earthquakes are common environmental catastrophes which occur as a result of overwhelming stress being released within the earth. The location of the San Francisco Bay Area is extremely vulnerable to megathrust earthquakes

According to Brillinger (2011), earthquakes were recorded after happening to get an earthquake statistics. Earthquakes may be large or small, serious or trivial; however, the higher the magnitude, the greater the damage to a particular location and the surrounding area. Earthquakes can also create other natural disasters, like tsunamis and volcanic eruptions, which bring more dangerous disasters than earthquakes. Statistics of earthquakes can be extremely important for it can give governments plans to do rebuilding after earthquakes, can help scientists better detect and anticipate earthquakes, and can provide more information to public to learn about earthquakes. It is helpful to take a look at existed statistics; from the website of US government,

Earthquakes are caused when rock at an underground fault breaks. This release of energy causes seismic waves (Endsley). There are P waves, S waves, and surface waves (Hogan). This is the main cause of earthquakes, though there has been a few, rare occurrences

The San Andreas Fault is one of the most widely studied faults in the world. Scientists use an array of methods in collecting data and providing analysis of fault characteristics both past and present. Presently there are many differing hypothesis and models used to describe crustal movements and deformation within the Pacific and North American plate boundary. Historical earthquakes along this fault have proven to be rather large and devastating. This is important since the San Andreas Fault runs along many highly populated areas throughout Northern and Southern California. Through further research and analysis of this fault system scientists hope to solve

     An Earthquake is the shaking of the earth's surface caused by rapid movement of the earth's rocky outer layer. The sudden shaking of the ground that occurs when masses of rock change position below the Earth's surface is called an earthquake. The shifting masses send out shock waves that may be powerful enough to alter the surface of the Earth, thrusting up cliffs and opening great cracks in the ground.

In the U.S. alone, the average annual cost to repair damage caused by earthquakes is $4.4 billion USD. The worldwide figure is much larger than this but unquantifiable due to poorer countries unable to accurately determine the amount of damage that occurred. Year after year the cost of damages barely fluctuates from these ridiculously high figures and money must be pumped into repairing the damage done. Although a lot is being learnt about earthquakes and the fact that humans are now normally able to be alerted in time to evacuate the area the earthquake will affect, there have been no breakthroughs into reducing the amount of damage earthquakes cause to buildings and infrastructures.