The Tokoku Earthquake
The Tohoku 2011 Earthquake hit off the Pacific coast of Tohoku, on Friday 11 March 2011 at 2:46pm. There was a magnitude 9.0–9.1, with the epicentre about 70 kilometres east of the Oshika Peninsula of Tohoku. The earthquake is also often referred to in Japan as the 'Great East Japan Earthquake', and also known as the 2011 tragic Tōhoku earthquake. It was the most powerful earthquake ever recorded to have hit Japan, and the fourth most powerful earthquake in the world! (since modern record-keeping began in 1900). The earthquake triggered high destructing tsunami waves that reached heights of up to 40.5 metres, in Miyako in Tōhoku's Iwate Prefecture and when in the Sendai area, traveled up to 10 km inland. The earthquake moved Honshu (the main island of Japan) 2.4 m east and shifted the Earth on its axis by estimates of between 10 cm and 25 cm.
On the 10th of March 2015, a Japanese National Police Agency report settled 15,894 deaths, 6 152 injured, and 2,562 people missing across twenty government buildings. Only to mention 228,863 people living away from their home in either temporary housing or due to permanent relocation. A 10th of February 2014 agency report listed 127,290 buildings collapsed, with a further 272,788 buildings "half collapsed", and another 747,989 buildings partially damaged. The earthquake and tsunami also caused extensive and severe structural damage in north-eastern Japan. Including heavy damage to roads and railways as well as fires in many areas, and a dam collapse. Japanese Prime Minister Naoto Kan said, "In the 65 years after the end of World War 2, this is the toughest and the most horrific crisis for Japan." Around 4.4 million houses in northeastern Japan were left without electricity and 1.5 million without water
Money Management Losses
Estimates placed insured losses from the earthquake alone at $18.91 to $45.12 billion AUD. The Bank of Japan offered ¥15 trillion to the banking system on the 14th of March in an effort to equalize market conditions. The World Bank's estimated financial cost was a $306.47 billion AUD, making it the most expensive natural disaster in world history.
The tectonic plates are positioned underneath our earth's crust, and make up Earth's outer shell, called the lithosphere, this includes the crust and upper part part of the mantle. Churning currents in the molten rocks below push them along, Most geologic activity stems from the interplay where the plates meet or divide. The movement of the plates create three types of tectonic boundaries convergent, where plates move into one another divergent, where plates move apart and transform, where plates move sideways in relation to each other.
Causes And Effects
One is Tectonic Movement: This particularly happens when the continental plate collides against the oceanic plate. The oceanic plate is overridden by the continental plate. By a process called subduction jerky movements are caused along the inclined surface. Tectonic earthquakes have occurred in Assam in the 1950s. Volcanic Activity: Earthquakes may also be caused by the movement of lava beneath the surface of the earth during volcanic activity. The earthquakes due to Krakatoa volcanic eruption in 1883 is a good example of volcanic eruption. Dislocation of the Earth’s crust: Earthquakes may be caused by the dislocation of the crust beneath the surface of the Earth.Adjustment in inner Rock Beds: Earthquakes are also caused where is an adjustment between Sima, this Earthquake may be called as a Plutonic Earthquake. Pressure of gases in the interior: The expansion and contraction of gases in the interior of the Earth sometimes cause a sudden shake on the Earth’s surface.Other Causes:Landslides and avalanches,Denudation of the Landmasses and depositions of materials. Man-made Earthquakes:The impounding of large quantities of water behind dams disturb the crustal balance. This causes earthquakes such as the Koyna earthquake in Maharashtra. Destructive Effects: Earthquake cause dismantling of buildings, bridge and other structures at or near the epic-enter. Many humans and animals are killed or buried under collapsed houses. Rails are folded, underground wires broken. Fire breaks out inevitably in large towns. Earthquakes make giant sea waves called Tsunamis.
The Richter scale was invented, in the 1930s by Dr. Charles Richter, a seismologist at the California Institute of Technology. It is a measure of the largest seismic wave recorded on a particular kind of seismograph located 100 kilometres from the epic-enter of the earthquake.
Think of a seismograph as a kind of sensitive time device that records the shaking of the Earth. Dr. Richter studied records from many earthquakes in southern California, and realized that some earthquakes made very small waves when others produced large waves. To make it easier to compare the sizes of the waves he recorded, Richter used the logarithms of the wave heights on seismograms measured in microns. Remember, you have to be using a particular kind of seismograph located 100 km from the epic-enter when you make the measurement otherwise, all sorts of complicated calculations have to be made.
A wave one millimetre (1000 microns) high on a seismogram would have a magnitude of 3 because 1000 is ten raised to the third power. In contrast, a wave ten millimetres high would have a magnitude of 4, a factor of 10 change in the wave height corresponds to a factor of 32 change in the amount of energy released during the earthquake. In other words, a magnitude 7 earthquake would produce seismogram waves 10 x 10 = 100 times as high and release energy 32 x 32 = 1024 times as great as a magnitude 5 earthquake. The Richter scale is open-ended, meaning there is no limit to how small or large an earthquake might be. Due to the nature of logarithms, it is even possible to have earthquakes with negative magnitudes, although they are so small that humans would never feel them. At the other end of the spectrum, there should never be an earthquake much above magnitude 9 on the Earth because it would require a fault larger than any on the planet.
Earthquake- a sudden violent shaking of the ground, typically causing great amounts of destruction.
P-wave- a longitudinal earthquake wave that travels through the interior of the Earth also known as Primary wave.
S-wave- secondary waves move through the body of an object.
Richter Scale- developed in the 1980's. A base 10 logarithmic scale, which defines magnitude as the logarithm.
Seismograph- is an instrument that measures and records any type of earthquake. Aftershock- is a smaller earthquake following the main shock of a large earthquake.