The Sumatra-Andaman portion of the collision zone forms a subduction zone megathrust plate boundary, the Sunda-Java trench, which accommodates convergence between the Indo-Australia and Sunda plates. This convergence is responsible for the intense seismicity and volcanism in Sumatra. The Sumatra Fault, a major transform structure that bisects Sumatra, accommodates the northwest-increasing lateral component of relative plate motion.
In Februaryscientists revised the estimate of the magnitude to 9. A study estimated a magnitude of Mw 9. This quickly elevated the height and increased the speed of waves, destroying the nearby Indonesian town of Lhoknga. The Sumatra earthquake is believed to have been a foreshockpreceding the main event by over two years.
Their seismic moments can account for a significant fraction of the global seismic moment across century-scale time periods. Of all the moment released by earthquakes in the years from throughroughly one-eighth was due to the Indian Ocean earthquake.
This quake, The sumatran tsunami of december 26 with the Good Friday earthquake Alaskaand the Great Chilean earthquakeaccount for almost half of the total moment. Sincethe only earthquakes recorded with a greater magnitude were the Great Chilean earthquake Magnitude 9.
The only other recorded earthquakes of magnitude 9. Each of these megathrust earthquakes also spawned tsunamis in the Pacific Ocean.
However, in comparison to the Indian Ocean earthquake, the death toll from these earthquakes was significantly lower, primarily because of the lower population density along the coasts near affected areas, the much greater distances to more populated coasts, and the superior infrastructure and warning systems in MEDCs More Economically Developed Countries such as Japan.
All of them are believed to be greater than magnitude 9, but no accurate measurements were available at the time. Plate tectonics Epicenter and associated aftershocks The Indian Ocean earthquake was unusually large in geographical and geological extent.
The slip did not happen instantaneously but took place in two phases over several minutes: The rupture proceeded at about 2. However, the northern rupture occurred more slowly than in the south, at about 2. The Indian Plate is part of the great Indo-Australian Platewhich underlies the Indian Ocean and Bay of Bengaland is moving north-east at an average of 6 centimetres per year 2.
The India Plate sinks deeper and deeper beneath the Burma Plate until the increasing temperature and pressure drive volatiles out of the subducting plate.
These volatiles rise into the overlying plate, causing partial melting and the formation of magma. The rising magma intrudes into the crust above and exits the Earth's crust through volcanoes in the form of a volcanic arc.
As well as the sideways movement between the plates, the Indian Ocean earthquake resulted in a rise of the sea floor by several metres, displacing an estimated 30 cubic kilometres 7.
This greatly increased the geographical area over which the waves were observed, reaching as far as Mexico, Chile, and the Arctic. The raising of the sea floor significantly reduced the capacity of the Indian Ocean, producing a permanent rise in the global sea level by an estimated 0.
List of earthquakes in Indonesia and List of earthquakes in Initial earthquake and aftershocks measuring greater than 4. Other aftershocks of up to magnitude 6. A week after the earthquake, its reverberations could still be measured, providing valuable scientific data about the Earth's interior.
The Indian Ocean earthquake came just three days after a magnitude 8. This is unusual, since earthquakes of magnitude 8 or more occur only about once per year on average. Geological Survey sees no evidence of a causal relationship between these events.
This energy is equivalent to over 1, times that of the Hiroshima atomic bombbut less than that of Tsar Bombathe largest nuclear weapon ever detonated; however, the total physical work done MW and thus energy by the quake was 4.
The only recorded earthquakes with a larger MW were the Chilean and Alaskan quakes, with 2. The seismic waves of the earthquake were felt across the planet; as far away as the U. The seismograms are arranged vertically by distance from the epicenter in degrees.
A major aftershock magnitude 7. The aftershock would be considered a major earthquake under ordinary circumstances but is dwarfed by the mainshock. The shift of mass and the massive release of energy slightly altered the Earth's rotation.
The exact amount is not yet known, but theoretical models suggest the earthquake shortened the length of a day by 2. The Andaman and Nicobar Islands appear to have shifted south-west by around 1.
The survey, conducted using a high-resolution, multi-beam sonar system, revealed that the earthquake had made a huge impact on the topography of the seabed. An oceanic trench several kilometres wide was exposed in the earthquake zone. Measurements from these satellites may prove invaluable for the understanding of the earthquake and tsunami.
A tsunami that causes damage far away from its source is sometimes called a teletsunami and is much more likely to be produced by vertical motion of the seabed than by horizontal motion. Bangladeshwhich lies at the northern end of the Bay of Bengalhad few casualties despite being a low-lying country relatively near the epicenter.
It also benefited from the fact that the earthquake proceeded more slowly in the northern rupture zone, greatly reducing the energy of the water displacements in that region.The great Sumatran earthquake of December 26, is the largest earthquake to have occurred in the past 40 years and is the first magnitude 9 earthquake to have occurred during the satellite era of geophysical measurements, thereby providing an unprecedented.
The Indian Ocean earthquake occurred at UTC on 26 December, ( mi) off the western coast of northern Sumatra, in the Indian Ocean just north of Simeulue island at a depth of 30 km (19 mi) below The Indian Ocean Tsunami warning system was formed in early to provide an early warning of tsunamis for inhabitants .
Sumatra Earthquake and Tsunami of December 26, , provided the world with images provoking both incredible sadness at the tragic loss of life, and awe at the destructive release of energy from one brief convulsion of Earthâ€™s crust. Mon, 17 Sep GMT Sumatra. On 26 December , a magnitude earthquake ( N, E, depth 30 km) occurred off the coast of northern Sumatra, Indonesia.
The tsunami generated by the earthquake was recorded nearly world-wide and killed more people than any other tsunami in recorded history, almost , missing and presumed dead.
The Sumatran earthquake and tsunami, which are feared to have caused more than , deaths, struck on December 26, The moment estimate (M0 = 5 dyne-cm), based on the measurement of split modes of free oscillations of Earth, is about three times larger than the 4 5 dyne-cm measured from traditional long-period surface waves.
The December 26, Sumatran Tsunami On th e morning of December 26, a magnitude earthquake struck off the Northwest coast of the Indonesian island of Sumatra. The earthquake resulted from complex slip on the fault where the oceanic portion of the Indian Plate slides under Sumatra, part of the Eurasian Plate.