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Chile Earthquake May Have Shortened Days on Earth 6 Months, 1 Week ago
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Karma: 37
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SPACE.com Space.com Staff
space.com – Tue Mar 2, 10:00 am ET
The massive 8.8 earthquake that struck Chile may have changed the entire Earth's rotation and shortened the length of days on our planet, a NASA scientist said Monday.
The quake, the seventh strongest earthquake in recorded history, hit Chile Saturday and should have shortened the length of an Earth day by 1.26 milliseconds, according to research scientist Richard Gross at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
"Perhaps more impressive is how much the quake shifted Earth's axis," NASA officials said in a Monday update.
The computer model used by Gross and his colleagues to determine the effects of the Chile earthquake effect also found that it should have moved Earth's figure axis by about 3 inches (8 cm or 27 milliarcseconds).
The Earth's figure axis is not the same as its north-south axis, which it spins around once every day at a speed of about 1,000 mph (1,604 kph).
The figure axis is the axis around which the Earth's mass is balanced. It is offset from the Earth's north-south axis by about 33 feet (10 meters).
Strong earthquakes have altered Earth's days and its axis in the past. The 9.1 Sumatran earthquake in 2004, which set off a deadly tsunami, should have shortened Earth's days by 6.8 microseconds and shifted its axis by about 2.76 inches (7 cm, or 2.32 milliarcseconds).
One Earth day is about 24 hours long. Over the course of a year, the length of a day normally changes gradually by one millisecond. It increases in the winter, when the Earth rotates more slowly, and decreases in the summer, Gross has said in the past.
The Chile earthquake was much smaller than the Sumatran temblor, but its effects on the Earth are larger because of its location. Its epicenter was located in the Earth's mid-latitudes rather than near the equator like the Sumatran event.
The fault responsible for the 2010 Chile quake also slices through Earth at a steeper angle than the Sumatran quake's fault, NASA scientists said.
"This makes the Chile fault more effective in moving Earth's mass vertically and hence more effective in shifting Earth's figure axis," NASA officials said.
Gross said his findings are based on early data available on the Chile earthquake. As more information about its characteristics are revealed, his prediction of its effects will likely change.
The Chile earthquake has killed more than 700 people and caused widespread devastation in the South American country.
Several major telescopes in Chile's Atacama Desert have escaped damage, according to the European Southern Observatory managing them.
A salt-measuring NASA satellite instrument destined to be installed on an Argentinean satellite was also undamaged in the earthquake, JPL officials said.
The Aquarius instrument was in the city of Bariloche, Argentina, where it is being installed in the Satelite de Aplicaciones Cientificas (SAC-D) satellite. The satellite integration facility is about 365 miles (588 km) from the Chile quake's epicenter.
The Aquarius instrument is designed to provide monthly global maps of the ocean's salt concentration in order to track current circulation and its role in climate change.
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More photos at Portrait Photographer Thailand website. - Jose Tan Photography
He who knows when he can fight and when he cannot, will be victorious. Sun Tzu
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Deadly Quakes 6 Months, 1 Week ago
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Karma: 45
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People look for family members among rubble on March 2, 2010 in the fishing village of Constitucion, central Chile. Thousands more troops deployed across Chile as armed vigilantes patrolled neighborhoods to ward off looters and soldiers began distributing emergency aid to desperate survivors.
Damaged buildings resulting from the 7.0 magnitude earthquake in the Caribbean nation of Haiti. The disaster struck on January 12, 2010. President Rene Preval estimated that thousands had been killed.
Tidal waves wash through houses at Maddampegama, about 60 kilometers (38 miles) south of Colombo, Sri Lanka, Sunday, Dec. 26, 2004. Massive waves triggered by earthquakes crashed into villages along a wide stretch of the Sri Lankan coast. There were a total of 283,106 deaths from the earthquake and tsunami.
Great Hanshin-Awaji (Kobe) Earthquake, January 16, 1995. The picture shows an office building with a partially destroyed first floor. The majority of partial or complete collapses were in the older, reinforced concrete buildings built before 1975. However, significant non-structural damage was also observed for buildings of relatively recent steel or composite construction.
Northridge, California Earthquake, January 17, 1994. A view of the parking structure on the campus of California State University. The bowed columns are of reinforced concrete. The structure has precast moment- resisting-concrete frames on the exterior and a precast concrete interior designed for vertical loads. The inside of the structure failed, and with each aftershock the outside collapsed slowly toward the inside until finally the west side failed totally. The reinforced concrete columns were extremely bent.
Northern Iraq Earthquake, June 21, 1990. Typical major damage to buildings with many unreinforced shear walls. Note "X-cracking." Unreinforced hollow or solid brick masonry infill, extensively used in Iranian buildings, performed poorly during this earthquake. In Rasht, sixty kilometers from the epicenter, the buildings incurred widespread damage due to such unreinforced masonry sheer walls. However, two thick solid unreinforced masonry walls were placed at the opposite ends of some mid-rise buildings in Rasht. These walls acted as shear resisting elements and appeared to have improved the overall performance of the buildings.
Loma Prieta, California, Earthquake October 17, 1989. San Francisco. An automobile lies crushed under the third story of this apartment building in the Marina District. The ground levels are no longer visible because of structural failure and sinking due to liquefaction.
The Armenia Earthquake, December 7, 1988. Collapse of old stone masonry Armenian church near Leninakan. Churches are vulnerable to earthquake damage because of their high unsupported roofs. Many such historical buildings either collapsed totally or sustained severe damage although some almost miraculously survived.
Mexico City Earthquake, September 19, 1985. The top floors of this eight-story building collapsed because of pounding against the next building.
Peru Earthquake May 31, 1970. Slumping and fissuring of the paved road near the bay shore in western Chimbote due to liquefaction and lateral spreading of water-saturated beach sediments. This earthquake, measuring 7.9 magnitude, was one of the deadliest earthquakes in history, responsible for 66,000 deaths and costing nearly $530,000,000 in damage.
The California earthquake of April 18, 1906 ranks as one of the most significant earthquakes of all time. It measured a magnitude of 7.8. Shaking damage was equally severe in many other places along the fault rupture. The frequently quoted value of 700 deaths caused by the earthquake and fire is now believed to underestimate the total loss of life by a factor of 3 or 4. Most of the fatalities occurred in San Francisco, and 189 were reported elsewhere. |
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 ...... Keep the Faith! ......  |
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Quake Moved Chilean City 10 Feet 5 Months, 4 Weeks ago
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Karma: 51
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The massive 8.8 magnitude earthquake that struck Chile more than a week ago moved the city of Concepción at least 10 feet (3 meters) to the west, seismological measurements indicate.
The violent temblor - the fifth most powerful quake ever measured - shifted other parts of South America as well, from the Falkland Islands (located just east of the southern tip of South America) to Fortaleza, Brazil, situated on that country's northern coast.
The quake occurred off the coast of the Maule region of Chile in one of Earth's seismic hotspots where the Nazca tectonic plate is squeezed under, or subducted below, the neighboring South American plate. Tension builds up as the plates move against each other, and earthquakes such as the one that struck Chile on Feb. 27 relieve these pent-up stresses.
The movements of the Earth during earthquakes can be measured by comparing the precise GPS locations of instruments prior to the quake and then after.
news.yahoo.com/s/livescience/20100309/sc...vedchileancity10feet |
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"With courage you will dare to take risks, have the strength to be compassionate, and the wisdom to be humble. Courage is the foundation of integrity."--- Keshavan Nair
"When you are content to be simply yourself and don't compare or compete, everybody will respect you." --- Lao Tzu
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