Earth’s Mantle in Overdrive Under Alaska

Posted on May 20, 2010 by Rashid Faridi

A computer generated model shows Alaskan mantle rock swirling around the plunging slab of crust (in gray) like water around a paddle dipped in a stream. Click to enlarge this image. Margarete Jadamec

A new 3-D model of the mega-quake and tsunami-launching subduction zone in Alaska has uncovered a big surprise: The Earth’s mantle there is moving a whopping 20 to 30 times faster than the crust.

So instead of being dragged along for the ride as a slab of crust is pushed under another, the solid rock mantle rock is swirling around the plunging slab like water around a paddle dipped in a stream.

What the models predict are flows up to 90 centimeters per year around the descending slab of crust, said geologist Magali Billen of the University of California at Davis. Billen co-authored a report on the new model with former graduate student and lead author Margarete Jadamec in this week’s issue of the journal Nature.

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Posted in earth, Earth Magnetism | Leave a comment

Arctic team reports unusual conditions near Pole

Posted on May 19, 2010 by Rashid Faridi

A group of British explorers  back from a 60-day trip to the North Pole said  they had encountered unusual conditions, including ice sheets that drifted far faster than they had expected.The three-member team walked across the frozen Arctic Ocean to study the impact of increased carbon dioxide absorption by the sea, which could make the water more acidic and put crucial food chains under pressure.Expedition leader Ann Daniels said the ice drifted so much that they eventually covered 500 nautical miles (576 miles) rather than the 268 nautical miles initially envisaged.

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Posted in climate change | 1 Comment

Hong Kong University tops in research output

Posted on May 18, 2010 by Rashid Faridi

India: According to a survey, Science Citations Index (SCI) Journal Publications and Citations 2002-2009 by Thomson Reuters, Land Surveying and Geo-Informatics Department of the Hong Kong Polytechnic University is at the top position with 784 citations. The university has the highest number of citations and publications per staff as well, 52.3 citations per staff and 14.1 publications per staff respectively. Geomatics Engineering Department of University of Calagary marked top position in publication category with 237 publications. Apart from these two universities, Geomatics Department of University of Melbourne; Surveying and Spatial Information Systems from University of New South Wales; Geodesy and Geomatics Engineering department of University of New Brunswick and Spatial Science Department of Curtin University of Technology also participated in this survey.

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Malaria risk prediction in Afghanistan using remote sensing

Posted on May 18, 2010 by Rashid Faridi

Malaria is a significant public health concern in Afghanistan. Currently, approximately 60% of the population, or nearly 14 million people, live in a malaria-endemic area. Afghanistan’s diverse landscape and terrain contributes to the heterogeneous malaria prevalence across the country. According to researchers, provincial monthly malaria cases can be modelled and predicted using satellite-measured environmental parameters with reasonable accuracy. The Third Strategic Approach of the WHO EMRO Malaria Control and Elimination Plan is aimed to develop a cost-effective surveillance system that includes forecasting, early warning and detection.

Researchers used provincial malaria epidemiological data (2004-2007) collected by the health posts in 23 provinces and applied in conjunction with space-borne observations from NASA satellites. Specifically, the environmental variables, including precipitation, temperature and vegetation index measured by the Tropical Rainfall Measuring Mission and the Moderate Resolution Imaging Spectoradiometer, were used. Regression techniques were employed to model malaria cases as a function of environmental predictors.The resulting model was used for predicting malaria risks in Afghanistan. The entire time series except the last 6 months is used for training and the last 6-month data is used for prediction and validation.Vegetation index of the result reflected the fact that irrigation is the main factor that promotes malaria transmission in Afghanistan. Surface temperature is the second strongest predictor. Precipitation is not shown as a significant predictor, as it may not directly lead to higher larval population.

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Posted in map making, Remote Sensing 101 | Leave a comment