2012 Indian Ocean earthquakes
Template: Infobox earthquake / Maintenance / Tote missing template: Infobox earthquake / Maintenance / injured missing template: Infobox earthquake / maintenance / property missing
(431 km from Banda Aceh )
The earthquake off Sumatra in 2012 was a major earthquake, the clock to 14:38 local time ( 8:38 UTC clock ) occurred off the coast of Sumatra in the Indian Ocean on 11 April 2012. The Research Centre for Geosciences Potsdam determined a moment magnitude of 8.6 and a depth of 10 km. The earthquake was the elftstärkste earthquake since 1900.
Tectonic overview
The earthquake of April 11, with a magnitude of 8.6 Mw off the west coast of the northern part of the Indonesian island of Sumatra occurred as a result of strike-slip fault within the oceanic lithosphere of the Indo -Australian plate. The center of the earthquake was about 100 km southwest of the Hauptsubduktionszone, which forms the boundary between the Indo -Australian plate and the Sundaplatte off the coast of Sumatra. In this area, the Indo- Australian Plate is moving at a speed of about 52 mm per year in relation to the Sundaplatte in north- northeasterly direction.
Large strike-slip earthquakes are not uncommon in this region of the Indo -Australian plate. Since the Sumatra - Andaman earthquake of December 2004 with a magnitude of 9.1 Mw, in which a 1300 km long segment of the Sumatra mega Thrust is open, three major strike-slip faults have occurred in the vicinity of the center of the earthquake of April 11. This happened on April 19, 2006 ( Mw = 6.2 ), on 4 October 2007 (Mw = 6.2 ) and 10 January 2012 (Mw = 7.2 ). In all three cases, the shift was similar. The focal mechanisms of the three previous earthquakes and the two large earthquakes of 11 April are consistent with each other and imply that each of the earthquake could have occurred as a result of left- slip fault along a north-northeast or as a right-side -slip fault along a west- northwest running fracture. These two different orientations are possible under the same tectonic stress field; right angles to each stationary blade displacement faults, each compatible with the same stress field, called " complementary fractures ". Maybe fractures of both orientations in the recent earthquake activity were involved.
Effects of the quake
The earthquake and the strong aftershock with a magnitude of 8.2 Mw the two respective plates have shifted about 21 m from each other - at the most famous in the public -slip fault, the San Francisco earthquake of 1906, the two sides had the San Andreas Fault moved against each other by about 4.5 m. The quake, according to the magnitude of the earthquake elftstärkste since 1900, while the strongest ever recorded earthquakes with a strike-slip fault, however, is debated among geophysicists as to whether the Assam earthquake in 1950 was equally strong.
Tsunami warning
The Pacific Tsunami Warning Center initially issued for the 28 states bordering the Indian Ocean, a Tsunami Warning, however, these canceled about three hours after the earthquake for most states and territories.
Reactions
The earthquake was felt due to its magnitude in many parts of South Asia and Southeast Asia, such as in the major Indian cities Chennai, Bangalore, Kochi, Bhubaneswar and Kolkata, on the west coast of the Malay Peninsula between Penang and Kuala Lumpur, Colombo, Sri Lanka, and on the Maldives, Singapore, Bangladesh, Burma, Vietnam and Thailand.
Aftershocks
In addition to several small quakes to an unusually severe aftershock of magnitude 8.2 occurred 250 km away at 10:43:09 UTC.