Cuánto se ha deformado la Tierra tras el terremoto de Japón?

La comunidad científica está utilizando los datos generados por el radar de apertura sintética (SAR) instalado a bordo del satélite Envisat de la ESA para medir la deformación de la superficie terrestre causada por el terremoto de magnitud 9 en la escala de Richter que azotó Japón a principios de marzo.

Comparando las imágenes tomadas los días 19 de febrero y 21 de marzo, un equipo de investigadores del laboratorio JPL de la NASA ha podido detectar un desplazamiento del terreno de 2.5 m en dirección este, y el hundimiento de la costa oriental de la isla Honshū, la mayor del archipiélago japonés. Científicos del Instituto Nacional Italiano de Geofísica y Vulcanología han utilizado las mismas observaciones de Envisat para trazar un mapa del desplazamiento del terreno en la región; las zonas coloreadas en rojo en la imagen de arriba se corresponden con un desplazamiento máximo de 2.5 m. Estos primeros resultados, que cubren una franja de 800 km sobre Sendai y Tokio, demuestran que la deformación del terreno se extiende a gran distancia del epicentro del seísmo, en el océano Pacífico.

La técnica empleada para analizar los datos de Envisat se conoce como ‘InSAR’ – interferometría con radar de apertura sintética – y se basa en la comparación de imágenes radar tomadas antes y después de la catástrofe desde el mismo ángulo, lo que permite detectar desplazamientos del terreno de hasta unos pocos milímetros. Como la órbita de Envisat sólo se repite cada treinta días, fue necesario esperar hasta el pasado día 21 de marzo para que el satélite se encontrase en la misma posición que ocupaba cuando tomó la imagen del 19 de febrero, de forma que los resultados fuesen comparables empleando esta técnica. Envisat continúa tomando imágenes de la región para ampliar el área de estudio.

Colaboración internacional
Este desastre natural constituye la primera vez que varias agencias espaciales – la ESA, el Centro Aeroespacial Alemán (DLR) y la Agencia de Exploración Aeroespacial Japonesa (JAXA) – comparten libremente los datos obtenidos por sus satélites SAR para ayudar a comprender mejor los procesos tectónicos de nuestro planeta, dentro de la iniciativa Geo-Hazard Supersites, coordinada por el Grupo de Observación de la Tierra (GEO). 

Geo-Hazard Supersites facilita el acceso de los científicos a las observaciones realizadas in-situ y desde el espacio, contando con un archivo de 20 años de observaciones radar. Este esfuerzo internacional, que recopila todos los datos disponibles hasta la fecha, es una forma eficaz de evaluar la vulnerabilidad de la región mientras se avanza en su reconstrucción, aseguran desde la ESA.

Elena Sanz31/03/2011 Etiquetas:terremotojapónsatéliteESA
 
CONTACT: 
EPA Press Office 
[email protected] 
  
FOR IMMEDIATE RELEASE: 
March 22, 2011 

Radiation Monitors Continue to Confirm That No Radiation Levels of Concern Have Reached the United States 

WASHINGTON
 – During a detailed analysis of four west coast RadNet air monitor filters, the U.S. Environmental Protection Agency (EPA) identified trace amounts of radioactive iodine, cesium, and tellurium consistent with the Japanese nuclear incident. These levels are consistent with the levels found by a Department of Energy monitor last week and are to be expected in the coming days. 

EPA’s samples were captured by three monitors in California and one in Washington State on Friday, March 18 and sent to EPA scientists for detailed laboratory analysis. The data was reviewed over the weekend and the analysis was completed Monday night.  The radiation levels detected on the filters from California and Washington monitors are millions of times below levels of concern. 

In addition, last night preliminary monitor results in Hawaii detected minuscule levels of an isotope that is also consistent with the Japanese nuclear incident. This detection varies from background and historical data in Hawaii. This isotope was detected at our fixed monitor in Hawaii, and it is far below any level of concern for human health.  The sampling filter from this monitor is being sent to our national radiation lab for further analysis.  

In a typical day, Americans receive doses of radiation from natural sources like rocks, bricks and the sun that are about 100,000 times higher than what we have detected coming from Japan. For example, the levels we’re seeing coming from Japan are 100,000 times lower than what you get from taking a roundtrip international flight. 

EPA is in the process of conducting detailed filter analyses for fixed monitors located in Oregon. 

EPA’s RadNet filter results for San Francisco, Seattle, Riverside and Anaheim, California detected minuscule quantities of iodine isotopes and other radioactive particles that pose no health concern at the detected levels. Below are the results of the detailed filter analysis. All of the radiation levels detected during the detailed filter analysis are millions of times below levels of concern. 

All units are in Picocuries per meter cubed. 

- Filter results for Anaheim, Calif. found: 
            Cesium-137: 0.0017 
            Tellurium-132: 0.012 
            Iodine-132: 0.0095 
            Iodine-131: 0.046 

- Filter results for Riverside, Calif. found: 
            Cesium-137: 0.00024 
            Tellurium-132: 0.0014 
            Iodine-132: 0.0015 
            Iodine-131: 0.011 
- Filter results for Seattle, Wash. found: 
            Cesium-137: 0.00045 
            Tellurium-132: 0.0034 
            Iodine-132: 0.0029 
            Iodine-131: 0.013 

- Filter results for San Francisco, Calif. found: 
            Cesium-137: 0.0013 
            Tellurium-132: 0.0075 
            Iodine-132: 0.0066 
            Iodine-131: 0.068 

EPA’s RadNet system is designed to protect the public by notifying scientists, in near real time, of elevated levels of radiation so they can determine whether protective action is required. In addition, an analysis of the filters in the monitors can identify even the smallest trace amounts of specific radioactive isotopes.

As part of the federal government’s continuing effort to make our activities and science transparent and available to the public, EPA will continue to keep RadNet data available at:http://www.epa.gov/japan2011/

 
CORPORATE RESPONSIBILITY | MARCH 16, 2011 | BY SUSTAINABLEBUSINESSPepsiCo Unveils 100 Percent Bio-Based Plastic Bottle

PepsiCo (NYSE: PEP) has developed what it says is the world's first PET plastic bottle made entirely from plant-based, fully renewable resources.

PepsiCo said its "green" bottle is 100 percent recyclable and will allow it to significantly reduce its carbon footprint.

In what seems like a clear show of one-upmanship, PepsiCo stated that the bottle "far surpasses existing industry technologies." Beverage rival Coca-Cola (NYSE: KO) in 2009 unveiled its Plant Bottle, which contains up to 30 percent bio-based material.

The PepsiCo bottle is made from bio-based raw materials, including switch grass, pine bark and corn husks.

Combining biological and chemical processes, PepsiCo said it has identified methods to create a molecular structure that is identical to petroleum-based PET (polyethylene terephthalate), which results in a bottle that looks and feels the same as existing PET beverage containers.

In the future, the company said it expects to broaden the renewable sources to include orange peels, potato peels, oat hulls and other agricultural byproducts from its foods business.

"PepsiCo is in a unique position, as one of the world's largest food and beverage businesses, to ultimately source agricultural byproducts from our foods business to manufacture a more environmentally-preferable bottle for our beverages business--a sustainable business model that we believe brings to life the essence of Performance with Purpose," said PepsiCo Chairman and CEO, Indra Nooyi.    

PepsiCo will pilot production of the new bottle in 2012.  Upon successful completion of the pilot, the company intends to move directly to full-scale commercialization.  

"By reducing reliance on petroleum-based materials and using its own agricultural scraps as feedstock for new bottles, this advancement should deliver a double win for the environment and PepsiCo," said Conrad Mackerron, Senior Program Director ofAs You Sow, a San Francisco-based foundation, which promotes corporate social responsibility through shareholder engagement.



Photo by Michel Filion/flickr/Creative Commons

 
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