A friend of mine who is an engineer tells me that engineers should construct buildings that will resist the impending earthquakes because these will most likely take place during their own lifetimes. So engineers themselves do the best job they can when they develop these constructions. Read more: Tectonic plates reverse their movement before major earthquakes.
Awareness, education and good engineering are crucial in preparing for the next big earthquake, says Sergio Barrientos. More than people died in the 8. What lessons did Chile learn from this disaster? We learn something every time there is a large earthquake and something fails.
For instance, in the last earthquake in , some buildings were severely damaged; some of them collapsed. So a new study on how soils should be classified with regard to their response has been one major difference in the updated building code.
Additionally, we now have a very good observational system so that the information we get from instruments distributed throughout the country can be incorporated in the seismic codes.
It is very important as well to understand regional earthquake hazards. Because we know that we will be facing damaging earthquakes in the future, we realize that it is best to be prepared, to mitigate earthquake risk through preventive measures and education. Of course, the advancement of knowledge about earthquakes is important as well. That is another very important domain. Read more: Magnitude 7. We are part of a system. The system is up and working and has been tested in the last few earthquakes.
It is getting better and better, particularly for tsunami warnings. For example, we did not perform that well on tsunami warnings during the earthquake in Chile. But since , things have changed a lot in Chile both in organization and coordination.
After recommendations made by several committees that visited Chile in the aftermath of the earthquake and evaluated the response systems, the different agencies were strengthened and developed protocols for a common response. We are currently advising people how to react in the case of a possible tsunami. The whole system is now working in tandem. We have all these joint efforts to provide more security to the communities. Apart from the strengthening of monitoring systems, education plays a major role.
This is done partly through simulations and drills in different communities. We carry out simulations with the people so they know how to react when the next earthquake comes. That is one aspect. The other one, of course, is at schools. We provide all the information to teachers and people in charge of children to teach them how to react during earthquakes.
Ross Stein , a research geophysicist at the Geological Survey, and his colleagues followed the seismic records of the aftershocks closely because their unusually large magnitudes caused anxiety. Chile has seen some of the most powerful quakes in history because of its location directly along what seismic experts call a "subduction zone. The collision between those two plates deep within the Earth's crust builds up powerful strain, and when that strain is released it creates thrust fault earthquakes and their aftershocks.
On the surface one side of the fault moves over the other - in this case on a fault that first ruptured more than 20 miles below the surface. The quakes that strike in California along the San Andreas Fault Zone are also caused by the grinding motion of two slabs of the earth's crust. But here the immense crustal slab called the Pacific Plate is constantly sliding northward against the North American Plate, and that motion generates what are called strike-slip quakes, where the two sides of a fault like the San Andreas move abruptly against each other when the fault ruptures underground.
The magnitude scale measurement for earthquakes is logarithmic, such that a 5. This visualization shows the landscape around the epicenter of the earthquake. This region of Chile has steep coastal cliffs, a high coastal plain, and further inland, the ridgelines of the Andes Mountains.
The Nazca plate under the ocean is heavier than the South American plate, which houses the continent. The Nazca plate slides eastward beneath the South America plate, forcing the lighter plate upwards. This subduction process is slow and steady in some locations, but gets stuck in others.
Stress builds up where the two plates are locked together until the rock reaches a breaking point. The fracture causes a sudden shift that sends shockwaves through the surrounding rock: an earthquake. In Chile, large earthquakes through recent history occur roughly every 25 to years apart.
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