steel_ag
8th November 2012, 06:16 PM
Source: http://en.wikipedia.org/wiki/1960_Valdivia_earthquake
The earthquake did not strike all the territory with the same strength; measured with the Mercalli scale, tectonically depressed areas suffered heavier damage. The two most affected areas were Valdivia and Puerto Octay near the northwest corner Llanquihue Lake. The overall picture of damage showed that Puerto Octay was the center of a north-south elliptical area in the Central Valley where the intensity was at its highest if not counting the Valdivia Basin.[7] East of Puerto Octay in a hotel in Todos los Santos Lake piles of plates were reported to have remained in place.[7]
Tectonic interpretation
The earthquake was a megathrust earthquake resulting from the release of mechanical stress between the subducting Nazca Plate and the South American Plate, on the Peru-Chile Trench. The focus was relatively shallow at 33 km, considering that earthquakes in northern Chile and Argentina may reach depths of 70 km. Subduction zones are known to produce the strongest earthquakes on earth as their particular structure allows more stress to build up before energy is released. Geophysicists consider it a matter of time before this earthquake will be surpassed in magnitude by another. The earthquake's rupture zone was 800 km long, stretching from Arauco (37° S) to Chiloé Archipelago (43° S). The rupture velocity has been estimated as 3.5 km per second.[8]
The earthquake did not strike all the territory with the same strength; measured with the Mercalli scale, tectonically depressed areas suffered heavier damage. The two most affected areas were Valdivia and Puerto Octay near the northwest corner Llanquihue Lake. The overall picture of damage showed that Puerto Octay was the center of a north-south elliptical area in the Central Valley where the intensity was at its highest if not counting the Valdivia Basin.[7] East of Puerto Octay in a hotel in Todos los Santos Lake piles of plates were reported to have remained in place.[7]
Tectonic interpretation
The earthquake was a megathrust earthquake resulting from the release of mechanical stress between the subducting Nazca Plate and the South American Plate, on the Peru-Chile Trench. The focus was relatively shallow at 33 km, considering that earthquakes in northern Chile and Argentina may reach depths of 70 km. Subduction zones are known to produce the strongest earthquakes on earth as their particular structure allows more stress to build up before energy is released. Geophysicists consider it a matter of time before this earthquake will be surpassed in magnitude by another. The earthquake's rupture zone was 800 km long, stretching from Arauco (37° S) to Chiloé Archipelago (43° S). The rupture velocity has been estimated as 3.5 km per second.[8]