NASA: It is happening now - Está sucediendo ahora - 09-03-11 - Shaking Intensity Christchurch Earthquake - Earthquake Shakes Ice from New Zealand Glacier

Open your mind, your heart to other cultures
Abra su mente, su corazón a otras culturas
You will be a better person
Usted será una mejor persona
RM

This photos have a big map, click to enlarge it

Estas fotos tienen un gran mapa, clic para alargarlas

It is a modern human tendency to focus on the number of an earthquake—specifically, the magnitude, or what people used to call the “Richter scale.” But the destruction from a quake usually has more to do with location and timing. Such was the case with the earthquake in Christchurch, New Zealand, on February 22, 2011.

A September 2010 earthquake centered 40 kilometers (25 miles) west of Christchurch, in the plains near Darfield, struck at 4:35 a.m., had a magnitude of 7.1, and caused some structural damage and one death (by heart attack). The earthquake in February 2011 occurred at 12:51 p.m. and just 10 kilometers (6 miles) from the center of Christchurch. It had a magnitude of 6.3, though was officially classified—scientifically speaking—as an aftershock of the 2010 quake. At least 166 people died, and the city of Christchurch was devastated structurally and emotionally. Many people are still missing.

The natural-color image above was captured on March 4, 2011, by the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite. Overlain on the map are seismological measurements of the ground shaking in the Christchurch area on February 22, as noted by the U.S. Geological Survey's Earthquake Hazard Program.

The deeper the red color of the circle, the more intense the “peak ground acceleration,” or shaking of the earth. Note how intensity is highest right around the most densely developed areas of Christchurch. City officials and news accounts also described liquefaction—the softening and loosening of the soil due to shaking and groundwater penetration—that was 300 to 500 percent worse than during the September 2010 earthquake.

There are two forms of energy that cause the shaking in an earthquake. “P” or primary waves provide the initial, often vertical, jolt that lifts people and structures off the ground. “S” or secondary waves lead to horizontal shaking. Most structures collapse during the longer-duration S waves because buildings are not designed to handle this side-to-side motion. In Christchurch, the quake occurred so close by that the lag between P and S waves was a mere second.

1. References

2. GeoNet (2011, March 4) Christchurch badly damaged by magnitude 6.3 earthquake. Accessed March 8, 2011.
3. GNS Science (2011, February 25) February 22nd earthquake in Christchurch. Accessed March 8, 2011.
4. New Zealand Herald (2011, February ) Christchurch earthquake: Levels of liquefaction 300-500 pc worse. Accessed March 8, 2011.
5. U.S. Geological Survey (n.d.) Shake Map: South Island of New Zealand. Accessed March 8, 2011.

NASA Earth Observatory image by Robert Simmon, using ALI data from the EO-1 Team and USGS Earthquake Hazard Program. Caption by Mike Carlowicz.

Instrument: 

EO-1 - ALI

The magnitude 6.3 earthquake that ravaged Christchurch, New Zealand, on February 22, 2011, also broke a 30 million-ton piece of ice off the Tasman Glacier. The ice broke into many smaller icebergs after falling into Tasman Lake. By the time the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite acquired this image on March 2, the icebergs had congregated at the far end of the lake.

In the false-color image, plant-covered land is red. The dirt-coated glacier is dark brown, matching the exposed rock in the surrounding Southern Alps. White snow tops the mountains to the west, and the river and lake—clouded with finely ground rock—are silver.

Situated about 200 kilometers (120 miles) west of Christchurch, Tasman Glacier is New Zealand’s largest and longest. It has been retreating in recent years, and shedding ice from its foot, or terminus, is one mechanism of retreat. The February 2011 earthquake provided the final pulse of energy to calve off ice that had been about to break off anyway.

By the end of 2007, the New Zealand National Institute of Water and Atmospheric Research (NIWA) reported that the Tasman Glacier had retreated five kilometers (about 3 miles) since 1976. Mounds of rocks—moraines—mark the former extent of the glacier and hem in the lake that has formed at its terminus.

Glaciers through New Zealand’s Southern Alps lost 11 percent of their volume between 1976 and 2007. Since then, the glaciers have either lost ice or held steady, depending on the amount of precipitation that fell during the year. According to NIWA, 90 percent of the ice lost from the 12 largest glaciers (including Tasman) can be traced to iceberg calving from the terminus or downwasting—melting on the surface that thins the glacier.

1. References

2. National Institute of Water and Atmosphere Research. (2009, November 18). Glaciers continue to shrink. Accessed March 3, 2011.
3. National Institute of Water and Atmosphere Research. (2010, November 5). Glacier snowline in steady state by end of summer. Accessed March 3, 2011.
4. National Institute of Water and Atmosphere Research. (2007, November 18). New Zealand glaciers shrinking. Accessed March 3, 2011.
5. New Zealand Department of Conservation. (2010). Aoraki/Mount Cook National Park. Accessed March 3, 2011.
6. New Zealand Press Association. (2011, February 23). Ice chunk breaks off Tasman Glacier. Stuff.co.nz. Accessed March 3, 2011.

NASA Earth Observatory image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Holli Riebeek.

Instrument: 

Terra - ASTER

NASA: It is happening now - Está sucediendo ahora - 09-03-11 - Shaking Intensity Christchurch Earthquake - Earthquake Shakes Ice from New Zealand Glacier

You have an alphabetical guide in the foot of the page in the blog: solitary dog sculptor
In the blog: Solitary Dog Sculptor I, the alphabetical guide is on the right side of the page
Thanks

Usted tiene una guía alfabética al pie de la página en el blog: solitary dog sculptor
En el blog: Solitary Dog Sculptor I, la guia alfabética está en el costado derecho de la página
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My blogs are an open house to all cultures, religions and countries. Be a follower if you like it, with this action you are building a new culture of tolerance, open mind and heart for peace, love and human respect.

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Mis blogs son una casa abierta a todas las culturas, religiones y países. Se un seguidor si quieres, con esta acción usted está construyendo una nueva cultura de la tolerancia, la mente y el corazón abiertos para la paz, el amor y el respeto humano.

Gracias :)