Surprise! Icebergs Spotted in Lake Superior




Though it's starting to feel like summer in the Great Lakes region, with temperatures soaring into the 80s (Fahrenheit), icebergs are still loitering in Lake Superior — a reminder of an especially harsh winter.

Last week, a marine warden with the Wisconsin Department of Natural Resources was patrolling Lake Superior when she spotted seagulls resting on a huge chunk of ice near Madeline Island, off the northern coast of Wisconsin.

"Normally the ice is mostly gone by end of April with some bays having some ice chunks floating around," said warden Amie Egstad. "We were doing commercial net checks and had been seeing the ice floating around the area. This one was the biggest we had seen so far."


The iceberg rose 12 to 14 feet (3.5 to 4 meters) above the water and stretched 40 feet (12 m) long and 20 feet (6 m) wide, though much of the block was hidden underwater, Egstad told Live Science in an email.

"The surface water temperature in this area is only 34 Fahrenheit [1.1 degrees Celsius] so it will be a bit before the ice is actually gone," Egstad said.

The giant ice cubes seen by Egstad are lingering after a frigid winter, during which ice covered nearly 100 percent of Lake Superior, the deepest, largest and northernmost of the five Great Lakes. In March, all five of the lakes combined hit 91 percent ice cover, the most ice since the record of 94.7 percent was set in 1979, according to the Great Lakes Environmental Research Laboratory.

At the end of May, Lake Superior surface-water temperatures were about 1 or 2 degrees Fahrenheit (0.5 or 1 degree Celsius) below their long-term average. However, scientists with the Great Lakes Integrated Sciences and Assessments Center (GLISA) forecast that surface temperatures over the deepest parts of the lake will still be in the 40s F (about 4 C), at least 6 degrees F below normal by August, because these deeper waters take longer to mix with the surface waters and get thoroughly warm.


Scientists say the winter's deep freeze will have lasting effects beyond persistent icebergs and colder-than-average water for swimming. The Great Lakes will likely have higher water levels and occasional blankets of fog as well.

"It's going to be the summer of fog. The water will stay really cold, but summer air tends to be warm and humid," Peter Blanken, a GLISA collaborator from the University of Colorado, explained in a statement. "And any time you get that combination, you're going to have condensation and fog — basically evaporation in reverse."

Chilly water will also delay the start of the yearly evaporation season by four to six weeks. Less evaporation could be a good thing for the Great Lakes, which last year experienced record low water levels. Lake Superior could see water-level gains of up to 10 inches (25 centimeters) by next spring, depending on rainfall, said GLISA climatologist John Lenters.


Original article on Live Science.





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Big earthquakes double in 2014




If you think there have been more earthquakes than usual this year, you're right. A new study finds there were more than twice as many big earthquakes in the first quarter of 2014 as compared with the average since 1979.

"We have recently experienced a period that has had one of the highest rates of great earthquakes ever recorded," said lead study author Tom Parsons, a research geophysicist with the U.S. Geological Survey (USGS) in Menlo Park, California.

                                                  Earthquakes larger than magnitude-7 since 2000.

But even though the global earthquake rate is on the rise,the number of quakes can still be explained by random chance, said Parsons and co-author Eric Geist, also a USGS researcher. Their findings were published online June 21 in the journal Geophysical Research Letters. [Image Gallery: This Millennium's Destructive Earthquakes]


With so many earthquakes rattling the planet in 2014, Parsons actually hoped he might find the opposite -- that the increase in big earthquakes comes from one large quake setting off another huge shaker. Earlier research has shown that seismic waves from one earthquake can travel around the world and trigger tiny temblors elsewhere.

"As our group has been interested in the ability of an earthquake to affect others at a global scale, we wondered if we were seeing it happening. I really expected we would see evidence of something we couldn't explain by randomness," Parsons told Live Science's Our Amazing Planet in an email interview.

The new study isn't the first time researchers have tried and failed to link one earthquake to another in time and across distance. Earlier studies found that the biggest earthquakes on the planet -- the magnitude-8 and magnitude-9 quakes -- typically trigger much smaller jolts, tiny magnitude-2 and magnitude-3 rumblers. Yet, no one has ever proven that large quakes unleash other large quakes. Finding a statistical connection between big earthquakes is a step toward proving such connections takes place.

But despite the recent earthquake storm, the world's great earthquakes still seem to strike at random, the new study found.

                                                                     Japan 2011

The average rate of big earthquakes -- those larger than magnitude 7 -- has been 10 per year since 1979, the study reports. That rate rose to 12.5 per year starting in 1992, and then jumped to 16.7 per year starting in 2010 -- a 65 percent increase compared to the rate since 1979. This increase accelerated in the first three months of 2014 to more than double the average since 1979, the researchers report.


The rise in earthquakes  is statistically similar to the results of flipping a coin, Parsons said: Sometimes heads or tails will repeat several times in a row, even though the process is random.

"Basically, we can't prove that what we saw during the first part of 2014, as well as since 2010, isn't simply a similar thing to getting six tails in a row," he said.

But Parsons said the statistical findings don't rule out the possibility that the largest earthquakes may trigger one another across great distances. Researchers may simply lack the data to understand such global "communication," he said.

"It's possible that global-level communications happen so infrequently that we haven't seen enough to find it among the larger, rarer events," Parsons said.

However, earthquakes smaller than magnitude-5.6 do cluster on a global scale, the researchers found. This suggests these less-powerful quakes are more likely to be influenced by others -- a finding borne out by previous research.

For example, the number of magnitude-5 earthquakes surged after the catastrophic magnitude-9 earthquakes in Japan and Sumatra, even at distances greater than 620 miles (1,000 kilometers), earlier studies found.

                                                                             Sumatra 2004








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