Friday, 21 December 2012

Six Real Threats Facing the US, Mayan is over



Misguided interpretations of the ancient Mayan calendar have led to rumors of the world ending on Dec. 21. Some doomsayers believe a rogue planet will crash into Earth, or that a solar storm will spell total destruction. Others think the planets and the sun will align to cause cataclysmic tidal effects, or that the North and South Poles will suddenly and catastrophically trade places.
  

These scenarios have been exhaustively debunked by scientists. NASA has already issued a press release dated Dec. 22 and titled "Why the World Didn't End Yesterday." The US Geological Survey (USGS) has its own message: Flimsy apocalyptic forecasts aside, the Earth still has a fearsome capacity to generate natural disasters on any day of any year.


While any one of these events did not wipe out all of humanity, here are six real and sometimes unpredictable threats that the USGS says Americans should be prepared for:-

Earthquakes

After a magnitude-6.3 earthquake killed more than 300 people in the Italian city of L'Aquila in 2009, six scientists and one government official were accused of being too reassuring about the risk of an earthquake prior to the deadly temblor. They were put on trial for manslaughter and found guilty in a verdict widely condemned by scientists.


Not only is it virtually impossible, for now at least, to make short-term predictions about the time and place of an earthquake, but long-term predictions only touch on the probability of future temblors. For example, the USGS points out that based on past events in California, there's roughly a two-in-three chance that a magnitude-6.7 or larger temblor will strike in the next 30 years in the San Francisco Bay Area. But the agency says scientists are refining their probability models to take into account recent earthquake activity to help predict a larger earthquake after an initial smaller one.

Volcanoes

There are dozens of active volcanoes in the United States, and, according to the USGS, many of them could blow their lid at any time. The Mount St. Helens eruption on May 18, 1980, stands out as the most dramatic in recent memory. It killed 57 people and devastated the surrounding landscape, with the hot gas and debris wiping out countless animals and destroying large swaths of forest.


The blast was preceded by a swarm of small earthquakes. Thought it can be tricky to use such tremors to predict whether an explosive volcanic eruption might actually take place, scientists with the USGS keep a close eye on these signs of unrest, which also might include changes in gas emissions.

Hurricanes

In the wake of Superstorm Sandy, Americans don't need to be reminded that hurricanes can unleash devastating force on coastal areas. The storm left more than 100 dead, thousands homeless and millions without power from the Caribbean to New England. It caused billions of dollars in damage, hitting New York and New Jersey especially hard. But maybe one of the more remarkable aspects of Sandy was that it lived up to the predictions that weather forecasters laid out days in advance.


Today scientists have better computer models to predict the behavior of the weather patterns in the atmosphere that spawn hurricanes. And researchers with USGS on the ground can help forecast the likelihood of beach erosion, overwash and inundation.

Landslides

Landslides might be underrated natural disasters. A recently gathered database put the death toll from landslides worldwide as much as 10 times higher than previously estimated. 32,300 people died in 2,620 landslides between 2004 and 2010. Previous estimates ranged from 3,000 to 7,000 fatalities.


Landslides occur in all 50 states, but affect some regions more than others. For example, the US West Coast is vulnerable during its rainy season from November to March. Landslides can result from earthquakes, volcanoes, man-made construction activities or changes in groundwater; people living on or below steep hill slopes are at high risk for landslide damage. The USGS is working with the National Weather Service on a prototype Debris Flow Warning System to map susceptible areas.

Wildfires

Record dry and hot weather in Colorado this summer sent wildfires ripping through the state, scorching some 300 square miles (800 square kilometers) and forcing thousands to evacuate. Considering global warming, some scientists warn that such blazes will become more commonplace.


Though the fires often move quickly and unpredictably, scientists are refining their forecasts by learning more about patterns, ignition sources and fire size from past data. The USGS is also involved in response efforts, providing firefighters with real-time maps and satellite images of wildfires to look at it from above.

Solar storms


The sun sometimes bombards our atmosphere with electromagnetic particles in a burst of material called a coronal mass ejection (CME). The worst such solar storm in history occurred in September 1859. It set off fires in telegraph offices and colorful aurora, normally visible only in polar regions, were observed as far south as Cuba and Hawaii. A storm that powerful today would wreak havoc on our communications systems, potentially resulting in blackouts that last for months, leaving planes and ships without working GPS units for navigation and putting banking networks offline.


Damaging solar storms occur about four times a decade, according to the USGS, and can be detected days in advance by monitoring the sun. The sun shifts through periods of quiet and high-action, peaking roughly every 11 years. We're currently entering a solar maximum, though it's not expected to be an especially active period.






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