According to the U. Geological Survey, the earthquake released energy comparable to 23, Hiroshima atomic bombs and had the largest recorded magnitude in 40 years.
Top 5 Essays on Earthquakes Geography Article shared by: An earthquake is a major demonstration of the power of the tectonic forces caused by endogenetic thermal conditions of the interior of the earth.
The number indicating magnitude or intensity M on Richter scale ranges between 0 and 9 but in fact the scale has no upper limit of number because it is a logarithmic scale.
It is estimated that the total annual energy released by all earthquakes is about ergs, most of this is from a small number of earthquakes of magnitude over 7. The Bihar earthquake measuring 8. The place of the origin of an earthquake is called focus which is always hidden inside the earth but its depth varies from place to place.
The science, that deals with the seismic waves, is called seismology. Volcanic activity is considered to be one of the major causes of earthquakes. In 2004 indian ocean earthquake and destructive, vulcanicity and seismic events are so intimately related to each other that they become cause and effect for each other.
In other words, each volcanic eruption is followed by earthquakes and many of the severe earthquakes cause volcanic eruptions. The explosive violent gases during the process of vulcanicity try to escape upward and hence they push the crustal surface from below with great force and thus is caused severe earth tremor of high magnitude.
It may be pointed out that the magnitude of such earthquakes depends upon the intensity of volcanic eruptions. The violent eruption of Krakatoa volcano between Java and Sumatra caused such a severe earthquake the impact of which was experienced as far away as Cape Horn some 12, km away.
Faulting and Elastic Rebound Theory: In fact, sudden dislocation of rock blocks caused by both tensile and compressive forces triggers immediate earth tremors due to sudden maladjustment of rock blocks.
Underground active fault zone was suggested as one of the possible causes of Koyna earthquake Maharashtra of December 11, The stretching and pulling of crustal rocks due to tensile forces is slow process.
The rocks continue to be stretched so long as the tensile forces do not exceed the elasticity of the rocks but as the tensile forces exceed the rocks elasticity, they are broken and the broken rock blocks try immediately to occupy their previous positions so that they may adjust themselves.
All these processes occur so rapidly that the equilibrium of the concerned crustal surface is suddenly disturbed and hence earth tremors are caused.
The famous earthquake of of California was caused due to creation of a massive fault in the Oven Valley.
Similarly, the Californian earthquake of April 18,was caused due to the formation of km long San Andreas Fault. The earthquake of Sagami Bay of Japan was also believed to have been triggered by big fault. Krishna Brahman and Janardhan G. They have claimed to have identified two active rift faults in Maharashtra beneath the Deccan Traps viz.
Kurduvadi rift and Koyna rift. According to them Koyna rift begins from Kaladgi in Karnataka and runs for a distance of km through Koyna and terminates 40 km west of Nasik. The km long Kurduvadi rift begins from 40 km south-west of Solapur and after running through Kurduvadi it merges with the Koyna rift to the north of Pune.
According to them Bhatsa Dam is located at the junction of Tawi and Koyna faults. They are of the opinion that gradual increase in the seismic events in Bhatsa Dam area since is because of active faulting beneath the basaltic crust.
The Assam earthquake, Bihar earthquake and Bhuj earthquake Gujarat of India were caused mainly by faulting. Hydrostatic Pressure and Anthropogenic Causes: It may be pointed out that the intensity of earthquake has been positively correlated with the levels of water in the reservoirs.
As per theory of the plate tectonics the crust or the earth is composed of solid and moving plates having either continental crust or oceanic crust or even both continental-oceanic crust.
These plates are constantly moving in relation to each Other due to thermal convective currents originating deep within the earth.
Thus, all the tectonic events take place along the boundaries of these moving plates. From the stand point of movement and tectonic events and creation and destruction of geomaterials the plate boundaries are divided into: Major tectonic events associated with these plate boundaries are ruptures and faults along the constructive plate boundaries, faulting and folding along the destructive plate boundaries and transform faults along the conservative plate boundaries.
All sorts of disequilibrium are caused due to different types of plate motions and consequently earthquakes of varying magnitudes are caused.The earthquake is a form of energy of wave motion transmitted through the surface layer of the earth in widening circles from a point of sudden energy release, the focus’.
The Great Earthquake and Tsunami of 26 December in Southeast Asia and the Indian Ocean. The epicenter of the 26 December earthquake was near the triple point junction of three tectonic plates where major earthquakes and tsunamis have occurred in the past.
The Great Tsunami of 26 December in the Indian Ocean. The Indian Ocean earthquake, and series of catastrophic tsunamis that followed in its wake, had a lesson to teach. The world community needs to put in place early detection systems, possibly sponsored by the United Nations, that would undoubtedly save urbanagricultureinitiative.comgh this earthquake happened close to large population centers that had little time to act even with warnings, nations farther.
proceedings of the fourteenth world conference on earthquake engineering beijing, china, While Japan may have the longest recorded history of tsunamis, the sheer destruction caused by the Indian Ocean earthquake and tsunami event mark it as the most devastating of its kind in modern times, killing around , people.
The Sumatran region is also accustomed to tsunamis, with earthquakes of varying magnitudes regularly occurring off the coast of the island. This eyewitness assessment of damage from the earthquake and tsunami yields lessons for engineers. On December 26, , at local time, a powerful earthquake, moment magnitude (MW) , occurred in the Indian Ocean.