Researchers show how far South American cities moved in quake

March 09, 2010

COLUMBUS, Ohio - The massive magnitude 8.8 earthquake that struck the west coast of Chile last month moved the entire city of Concepcion at least 10 feet to the west, and shifted other parts of South America as far apart as the Falkland Islands and Fortaleza, Brazil.

These preliminary measurements, produced from data gathered by researchers from four universities and several agencies, including geophysicists on the ground in Chile, paint a much clearer picture of the power behind this temblor, believed to be the fifth-most-powerful since instruments have been available to measure seismic shifts.

Buenos Aires, the capital of Argentina and across the continent from the quake's epicenter, moved about 1 inch to the west. And Chile's capital, Santiago, moved about 11 inches to the west-southwest. The cities of Valparaiso and Mendoza, Argentina, northeast of Concepcion, also moved significantly.

The quake's epicenter was in a region of South America that's part of the so-called "ring of fire," an area of major seismic stresses which encircles the Pacific Ocean. All along this line, the tectonic plates on which the continents move press against each other at fault zones.

The February Chilean quake occurred where the Nazca tectonic plate was squeezed under, or "subducted," below the adjacent South American plate. Quakes routinely relieve pent-up geologic pressures in these convergence zones.

The research team deduced the cities' movement by comparing precise GPS (global positioning satellite) locations known prior to the major quake to those almost 10 days later. The US Geological Survey reported that there have been dozens of aftershocks, many exceeding magnitude 6.0 or greater, since the initial event February 27.

Mike Bevis, professor of earth sciences at Ohio State University, has led a project since 1993 that has been measuring crustal motion and deformation in the Central and Southern Andes. The effort, called the Central and Southern Andes GPS Project, or CAP, hopes to perhaps triple its current network of 25 GPS stations spread across the region.

"By reoccupying the existing GPS stations, CAP can determine the displacements, or 'jumps', that occurred during the earthquake," Bevis said. "By building new stations, the project can monitor the postseismic deformations that are expected to occur for many years, giving us new insights into the physics of the earthquake process."

Ben Brooks, an associate researcher with the School of Ocean and Earth Science and Technology at the University of Hawaii and co-principal investigator on the project, said that the event, tragic as it was, offers a unique opportunity to better understand the seismic processes that control earthquakes.

"The Maule earthquake will arguably become one of the, if not the most important great earthquake yet studied. We now have modern, precise instruments to evaluate this event, and because the site abuts a continent, we will be able to obtain dense spatial sampling of the changes it caused.

"As such the event represents an unprecedented opportunity for the earth science community if certain observations are made with quickly and comprehensively," Brooks said.

Working with Bevis and Brooks on the project are Bob Smalley, the University of Memphis, who is leading field operations in Argentina; Dana Caccamise at Ohio State, who is lead engineer, and Eric Kendrick, also from Ohio State, who is with Bevis now in Chile making measurements in the field.

Along with Ohio State University and the University of Hawaii, scientists from the University of Memphis and the California Institute of Technology are participating in the project. Additionally the Instituto Geografica Militar, the Universidad de Concepcion and the Centro de Estudios Cientificos, all in Chile, also were partners.

In Argentina. the Instituto Geografica Militar, the Universidad Nacional de Cuyo in Mendoza and the Unversidad Nacional de Buenos Aires are collaborating in the work. UNAVCO, a consortium of more than 50 institutions and agencies involved in research in the geosciences, is providing equipment for the project.

The researchers have constructed a map showing the relative movement of locations after the Maule, Chile earthquake. Images showing that map are available at http://researchnews.osu.edu/archive/chilequakemap.htm

The Ohio State University

---

---

	2:46: Aftershocks: Stories from the Japan Earthquake by The quakebook community (Author), Our Man in Abiko (Editor) In just over a week, a group of unpaid professional and citizen journalists who met on Twitter created a book to raise money for Japanese Red Cross earthquake and tsunami relief efforts. In addition to essays, artwork and photographs submitted by people around the world, including people who endured the disaster and journalists who covered it, 2:46: Aftershocks: Stories from the Japan Earthquake contains a piece by Yoko Ono, and work created specifically for the book by authors William Gibson, Barry Eisler and Jake Adelstein. “The primary goal,” says the book's editor, a British resident of Japan, “is to record the moment, and in doing so raise money for the Japanese Red Cross Society to help the thousands of homeless, hungry and cold survivors of the earthquake and tsunami. The...
	Earthquakes (reillustrated) (Let's-Read-and-Find-Out Science 2) by Franklyn M. Branley (Author), Megan Lloyd (Illustrator) Read and find out about one of nature's most mysterious forces—the earthquake. Some earthquakes are so small that you don't even feel them, while others can make even big buildings shake! Learn why earthquakes happen, where they are most likely to occur, and what to do if one happens near you.
	The San Francisco calamity by earthquake and fire by Charles Morris (Author) The San Francisco calamity by earthquake and fire is presented here in a high quality paperback edition. This popular classic work by Charles Morris is in the English language, and may not include graphics or images from the original edition. If you enjoy the works of Charles Morris then we highly recommend this publication for your book collection.
	A Study Of Recent Earthquakes by Charles Davison (Author) This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ...
	How to Survive An Earthquake: The Simple 5 Step Plan For Disaster & Emergency Preparedness, Response and Recovery - Buy It Now! If your family is involved in and survives a major earthquake, and you can dial 911, how long do you think it will take to get help? Most people think hours. In fact it could be days, if ever. Will you survive?  Will your family? Everyone wants to believe they and their families are safe. Unfortunately most people respond to the growing awareness of potential disasters by ignoring the issue and doing nothing. Think about this question. Have you ever had the chance to save someone's life? If you could spend a couple hours of your time to save your own life and your whole families, would you take the time to learn something important? In just a few short hours it is possible to create a simple but effective earthquake plan, engage...
	Haiti After the Earthquake by Paul Farmer (Author) On January 12, 2010 a massive earthquake laid waste to Port-au-Prince, Haiti, killing hundreds of thousands of people. Within three days, Dr. Paul Farmer arrived in the Haitian capital, along with a team of volunteers, to lend his services to the injured.In this vivid narrative, Farmer describes the incredible suffering--and resilience--that he encountered in Haiti. Having worked in the country for nearly thirty years, he skillfully explores the social issues that made Haiti so vulnerable to the earthquake--the very issues that make it an "unnatural disaster." Complementing his account are stories from other doctors, volunteers, and earthquake survivors.Haiti After the Earthquake will both inform and inspire readers to stand with the Haitian people against the profound economic and social...
	Time For Kids: Earthquakes! by Editors of TIME For Kids (Author) Earthquakes A small earthquake may just rattle some teacups. But a rare huge quake can bring down cities. Those rumblings are a reminder to pay attention to our earth. Scientists keep careful records of quakes around the world. They try to predict when the next one will happen.
	DK Readers: Earthquakes and Other Natural Disasters by Harriet Griffey (Author) DK is reissuing some of its most beloved Readers with a fresh new look, perfect for 21st century kids! From the eruption of Mount Vesuvius to the San Francisco earthquake of 1906, Earthquakes and Other Natural Disasters brings readers face to face with some of the deadliest natural disasters of all time and teaches the scientific forces that cause these incredible events.
	Jump into Science: Earthquakes by Ellen J. Prager (Author), Susan Greenstein (Illustrator) What causes earthquakes? Where do they happen most? What should you do if you feel the earth shake? Just follow the friendly crow-in-the-know for all the answers!
	Earthquake!: A Story of the San Francisco Earthquake (Once Upon America) by Kathleen V. Kudlinski (Author) In 1906, after a devastating earthquake hits San Francisco, twelve-year-old Philip struggles to save the horses in his family's livery stable. Reprint. SLJ.