Wednesday, October 31, 2012

How big and serious is Sandy and why?

More at: http://thewatchers.adorraeli.com/2012/10/30/how-big-hurricane-sandy/


Sandy is now post-tropical cyclone. Regardless its hurricane status, Sandy, dubbed Frankenstorm, is a massive system that will affect a huge swath of the eastern U.S. It is now evident that it may become the biggest storm of century. The circulation of Sandy could cover each of the 26 states east of the Mississippi River by Tuesday! Winds and clouds from Hurricane Sandy could stretch across the eastern third of the United States, according to weather predictions from the National Hurricane Center (NHC).

Sandy’s main features

Sandy is morphing from a tropical cyclone to an extra-tropical cyclone which tend to be significantly larger than tropical ones. Extra-tropical cyclones are driven by a difference in temperatures over a wide area— cold air to the northwest, warm air to the southeast, which then swirls together. Hurricane Sandy formed as a tropical cyclone, fueled by warm waters and warm  moisty air. Ample warm, moist air in the western Caribbean allowed Sandy to grow into a tropical cyclone and hurricane shortly after.
Dawn to Dusk: Hurricane Sandy, October 28, 2012, Super Rapid Scan
This time-lapse animation above shows Hurricane Sandy from the vantage point of geostationary orbit—35,800 km (22,300 miles) above the Earth on October 28, 2012. Light from the changing angles of the sun highlight the structure of the clouds. The images were collected by NOAA’s GOES-14 satellite. The “super rapid scan” images—one every minute, reveal details of the storm’s motion.
The video above shows Hurricane Sandy’s development on October 29, recorded from 11:15:00 UTC till 21:21:00 UTC.
Sandy is progressing into an extra-tropical cyclone as it gets farther north, and tapping into the power of the jet stream, which ferries air from west to east over North America. The jet stream, like the storm itself, is powered by this temperature difference between air masses, according to  Chris Davis, a scientist with the University Corporation for Atmospheric Research in Boulder, Colorado. Sandy is also deriving power from the movement of warm air to the north and cold air to the south, similar in some respects to the Perfect Storm of 1991. What we are seeing now from Sandy is a rare mix of a hurricane and a cold front jet stream. The upper level wind  is merging with the tropical system creating a “monstrous hybrid vortex” – a combination of a hurricane and a nor’easter according to Weather Channel hurricane specialist Bryan Norcross.
Weather experts agree that there has never been a storm like Hurricane Sandy in the history of modern meteorology.

How big is Sandy?

Sandy’s winds cover an area of more than 1,000 miles (1610 km) in diameter. Sandy now has the largest tropical storm-force wind field of any Atlantic tropical cyclone since 1988, topping Olga when it was a subtropical storm in 2001 according to Dr. Jeff Masters of Weather Underground. Olga’s winds extended out 600 miles (965 kilometers).
Let’s see some peak diameters of large hurricanes and their tropical wind extensions. Probably the largest was Isabel in 2003 which grew up to 575 miles (925 km) in diameter. Isabel’s hurricane-force wind field reached a diameter of 230 miles (370 km) before making landfall in September 2003. Hurricane Ike reached 485 miles (780 km) in diameter in 2008 and devastating Katrina peaked with 435 miles (700 km) in diameter in 2005. Last year, Irene’s wind field extended up to 460 miles (740 km) in diameter. Hurricane Sandy is wider and stronger than Hurricane Irene, which caused more than $15 billion in damage in 2011, and could rival the worst East Coast storm on record. Total damage from Hurricane Sandy may well exceed Katrina’s $96 billion. This could be the first $100+ billion storm in U.S. history.

Comparison of hurricanes Irene and Sandy captured by MODIS satellite

NASA's Terra satellite captured this image of Hurricane Sandy at 12 PM Eastern on Oct. 28, 2012.

Low pressure record

Sandy reached minimum central pressure of 938 mB. If Sandy reaches 934, she will be one of only 19 Atlantic hurricanes to achieve pressure that low, none of which had that pressure north of the Outer Banks. Northwest Atlantic pressure record is set by Hurricane Gladys in 1975, reaching 939 mB. According to AccuWeather Virginia, Maryland, Delaware and New Jersey would break their all-time pressure records. New York City, Block Island, RI and Nantucket, MA would break their all-time low pressure readings.
“Perfect Storm” of 1991 reached minimum central pressure of  972 mB. Great Blizzard of 1993 reached 960 mB and New England Hurricane, also known as Long Island Express of 1938,  reached 947 mB.

Suomi NPP Day/Night Band and 11.45 µm micron imagery of Hurricane Sandy
Watch here the satellite loop showing a series of full-resolution images taken one minute apart as Sandy approaches the East coast.
If this all happens as forecasted, and you and your family are stuck in the cold and dark without food and light and communications because you didn’t run to the store and get ready, excuses are going to be spectacularly hard to come by.” – Bryan Norcross, hurricane specialist for The Weather Channel

FORECAST

There will be some far-reaching effects aside from the most destructive impacts of storm surge flooding and high winds in the Northeast closer to the center of circulation. Sandy’s wind field will grow larger as the system begins to interact with a dip in the polar jet stream, deepening low pressure at the surface. It’s expected to change from a tropical storm powered by warm ocean water to something more like a winter storm powered by temperature and pressure differences in the atmosphere. Forecasters say Sandy may actually gain strength slightly as it reaches land, it will remain strong enough once on land to produce strong winds far inland. Wind damage will spread well inland, especially over higher terrain, due to the extremely large size of Sandy. In some areas, sustained winds of 30 to 50 mph could last for more than 24 hours. Gusts may top 80 mph in some locations. Lakeshore flood warnings have been hoisted on parts of the Great Lakes including Chicago.
Cold Arctic air coming south from Canada also is expected to merge with Sandy, which will strengthen the storm further and create winter storm conditions. Sandy will bring cold air and snow as well as wind and rain. Forecasters expect Sandy to meet a mass of very cold air from a winter storm about the time it reaches land. This cold air will be incorporated into the hurricane, which means in some places torrential rains will be followed by temperatures in the 20s. Sandy is expected to produce two feet of snow or even more in parts of West Virginia. So the problems of extreme winter and summer weather will be wrapped into one storm.  The combination of snow and strong winds will damage trees and cause power outages. The heavy, wet nature of the snow could cause some structural damage and roof collapses. The snow will continue for several days wrapping around Sandy’s circulation as it winds down slowly.
Heavy snow and strong winds will cause statewide power outages. Millions of people are expected to lose power at some point during Sandy and many will likely not have power restored for many days. That could be a major concern, especially in terms of heating.

The most recent orbit from NOAA and NASA’s latest weather satellite, Suomi NPP, acquired at 1:35 pm ET on October 29, 2012, shows Hurricane Sandy as it approaches the U.S. coastline. (Credit: NASA/NOAA/VIIRS)

ALERT: Emergency Declared At Oyster Creek Nuke Plant



This could get ugly in a hurry.  Oyster Creek is the same design, but even older than Fukushima, and acccording to Reuters, just 6 more inches of water will completely submerge the cooling pump.


(Reuters) - Exelon Corp declared an "alert" at its New Jersey Oyster Creek nuclear power plant due to a record storm surge, the Nuclear Regulatory Commission said, warning that a further water rise could force the country's oldest working plant to use emergency water supplies to cool spent uranium fuel rods.

The alert came after water levels at the plant rose by more than 6.5 feet, potentially affecting the pumps that circulate water through the plant, an NRC spokesman said late on Monday.  A further rise to 7 feet could submerge the service water pump motor that is used to cool the water in the spent fuel pool.


In the wake of Fukushima, the U.S. nuclear industry has pledged to bring additional backup equipment such as generators, pumps, hoses, and batteries to keep plants operating in case of loss of power or water, but that deployment is still under way.  Some critics have raised concerns about the safety of spent fuel at Oyster Creek and other nuclear plants, noting that the cooling pools where it is stored are not required to have backup power.  Spent fuel rods are still radioactive and continue to generate significant heat for decades.  Without cooling, the pools would boil away, leaving the fuel vulnerable to damage and to causing a radioactive release.  Exelon says it has "numerous, redundant backup cooling systems."

However, as discussed below by nuclear expert Arnie Gundersen, there is NO backup diesel generator for the spent fuel pool at Oyster Creek.

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Don't skip this.  Arne Gunderson discusses Oyster Creek:

Interview runs 5 minutes.  Gunderson on Democracy Now yesterday:

"There is NO backup generator for the spent fuel pool at Oyster Creek."

"The biggest problem, as I see it right now, is the Oyster Creek plant.  Oyster Creek is the same design, but even older than Fukushima Daiichi unit 1.  It’s in a refueling outage.  That means that all the nuclear fuel is not in the nuclear reactor, but it’s over in the spent fuel pool.  And in that condition, there’s no backup power for the spent fuel pools.  So, if Oyster Creek were to lose its offsite power — and, frankly, that’s really likely — there would be no way cool that nuclear fuel that’s in the fuel pool until they get the power reestablished.  The most important lesson we can take out of the Fukushima Daiichi incident, especially with Hurricane Sandy, is that we can’t expect to cool these fueling pools."

Fukushima government “Radiation test of beef overrides urine test of the children”


The Fukushima Prefectural Government drew up proceedings for a health research panel prior to a formal July 2011 meeting on nuclear radiation, deciding in advance what members should say. (cf.[Mainichi] Fukushima Prefecture prepared proceedings for nuke radiation meeting)

In the manual, they made this statement.

“Considering the potential spread of WBC (Whole body counter) and the fact that germanium semiconductor detector is in excessive demand such as for beef, it is impossible to replace WBC with urine test.”

WBC is the equipment to detect gamma ray from cesium taken in body. Because it lacks accuracy and requires the testee to stay still for long time, it is not suitable for children. Urine test with germanium semiconductor detector analyzes more accurately.

However, because they wanted to use germanium semiconductor detector for the radiation test of beef, they decided not to conduct urine test of the children.

Tokyo newspaper reported on 10/25/2012:




Tuesday, October 30, 2012

More about Sandy the Frankenstorm!

Hurricane Sandy Impacts 24 States: Map



Frightening NWS Sandy Update Map: 5 Day Projection





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Water Pours into Hoboken Path Station: Don’t need to say much about this security camera.  It’s going to be quite a cleanup.


Sharks Swimming In NJ Now: I will admit, it is bad here! The wind has been non-stop and its’ been raining quite heavily, too. Still, at least I don’t have to look out my front door and see this!



Lights out, Manhattan. Creepy. From promenade. 

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New York Subway Flooded
Superstorm Sandy slammed into the New Jersey coastline with 80 mph winds Monday night and hurled an unprecedented 13-foot surge of seawater at New York City, flooding its tunnels, subway stations and the electrical system that powers Wall Street. At least 13 U.S. deaths were blamed on the storm, which brought the presidential campaign to a halt a week before Election Day.

For New York City at least, Sandy was not the dayslong onslaught many had feared, and the wind and rain that sent water sloshing into Manhattan from three sides began dying down within hours.

Still, the power was out for hundreds of thousands of New Yorkers and an estimated 5.7 million people altogether across the East. And the full extent of the storm’s damage across the region was unclear, and unlikely to be known until daybreak.

In addition, heavy rain and further flooding remain major threats over the next couple of days as the storm makes its way into Pennsylvania and up into New York State. Near midnight, the center of the storm was just outside Philadelphia, and its winds were down to 75 mph, just barely hurricane strength.

“It was nerve-racking for a while, before the storm hit. Everything was rattling,” said Don Schweikert, who owns a bed-and-breakfast in Cape May, N.J., near where Sandy roared ashore. “I don’t see anything wrong, but I won’t see everything until morning.”

As the storm closed in, it converged with a cold-weather system that turned it into a superstorm, a monstrous hybrid consisting not only of rain and high wind but snow in West Virginia and other mountainous areas inland. 




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A huge explosion has been filmed at a power plant in downtown Manhattan after Hurricane Sandy made landfall.




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Meteorologist: Sandy Is Manufactured
Alex Jones welcomes meteorologist and award winning television weatherman Scott Stevens to explain how it’s possible that “Frankenstorm” Hurricane Sandy could be manipulated with military technology already at our disposal.



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Hurricane Sandy Sinks HMS Bounty, 2 Missing

The crew aboard the HMS Bounty 90 miles southeast of Hatteras N.C., in the Atlantic Ocean had to abandon ship, according to the U.S. Coast Guard. Fourteen members crew were rescued from open water early Monday, while a few still remain missing.

The Coast Guard’s news release stated the life-jacket-wearing crew boarded two life boats among 18-foot seas with 40 mile per hour winds.

The Associated Press reported the crew being composed of 16 members, two of which remained missing. But the Facebook page for the ship says the crew included 17, meaning three would still be unaccounted for. The rescue took place at 6:30 a.m. Monday.



Latest Hurricane Sandy Satellite Photos

If you had any doubts about the scale of Frankenstorm Sandy, check out NASA's latest global Earth image to see its size compared to the entire planet. We are now updating this post with images, video and warnings from NASA, NOAA and other sources as they arrive.
Update 17: Latest update from the National Hurricane Center says the storm strength has increased. "The center is expected to landfall along or just south of southern New Jersey coast this evening or tonight."

New York is flooding already and the storm is NOT in full force yet. This one could really flood the subway system.

According to NOAA, "Sandy is expected to intensify as it interacts with an upper level system moving from the Great Lakes." The northeast region "may experience a widespread damaging storm, possibly of historic proportions".

The agency says "Sandy is expected to slam into the New Jersey coast later monday night, bringing heavy rain and damaging winds" to all areas. They warn that you shouldn't pay attention to the center of the storm, as all areas will have significant impact.

This is getting kind of scary—Sandy is hitting so hard that could really flood the New York City's subway system. Learn about it here

Parts of Manhattan, Brooklyn and Queens are already flooding and the storm isn't over the city in full force yet. That will happen around 4pm today. Take a look at these images, taken just a few minutes ago:

"The Hudson River has breached its banks 8.53 am" by Nigel Barker.

"East River rises above last two steps of Get Down, and approaches 3rd, at end of Wall Street"by Arturas Rosenbacher.

Here we are marooned in Red Hook, Brooklyn!!" by Greenpainting


The flooding in the Jamaica Bay, Queens neighborhood of Meadowmere. Courtesy of Kim Zatto, bait purveyor" by Corey Kilgannon.

Update 15: NASA's night shot, acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite around 2:42am EDT.

Update 14: NPR just reported that Starbucks have closed all its locations in NYC. How's that for a disaster? They also say this may be the biggest storm ever in the region.

Update 13: If you think Sandy is going to be just another Irene fizzle, think again; this animated GIF shows just how much stronger Sandy is at this stage in the game. And it's only getting stronger.



Monday, October 29, 2012

100,000 Fled To Higher Ground In Hawaii From Tsunami From 7.7 Earthquake Off Vancouver


Tsunami warnings prompted by a 7.7  earthquake off the Canadian coast on Friday caused more than 100,000 people to flee from Hawaiian shores to higher ground in the state late on Saturday evening, but the evacuation order was canceled after a series of smaller than expected waves crashed on the islands  The tsunami was unusual in that it came from the east, an ocurrence that had not been observed for hundreds of years.  Geologists say  the 7.7 quake could be a precursor to a larger earthquake but there is no way of knowing.   The Canadian quake was in the Cascadia earthquake zone. 

A tsunami was generated that could have caused damage along  coastlines of all islands in the state of Hawaii. Urgent action was urged yesterday to protect lives and property.

The 1700 Cascadia earthquake was a magnitude 8.7 to 9.2 megathrust earthquake that occurred in the Cascadia subduction zone on January 26, 1700. The earthquake involved the Juan de Fuca Plate underlying the Pacific Ocean, from mid-Vancouver Island in British Columbia, Canada, south along the Pacific Northwest coast as far as northern California, USA. The length of the fault rupture was about 1,000 kilometers (620 miles) with an average slip of 20 meters (22 yards).

The earthquake caused a tsunami that struck the coast of Japan and Hawaii and may also be linked to the Bonneville Slide.

A tsunami is a series of long ocean waves. Each individual wave crest can last 5 to 15 minutes or more and extensively flood  coastal areas. The danger can continue for many hours after the initial wave as subsequent waves arrive. Tsunami wave heights cannot be predicted and the first wave may not be the largest.

The geological record reveals that “great earthquakes” (those with moment magnitude 8 or higher) occur in the Cascadia subduction zone about every 500 years on average, often accompanied by tsunamis. There is evidence of at least 13 events at intervals from about 300 to 900 years with an average of 570—590 years. Previous earthquakes are estimated to have occurred in 1310 AD, 810 AD, 400 AD, 170 BC and 600 BC.


Credit: Wikipedia

As seen in the 1700 quake, the 2004 Indian Ocean earthquake, and the 2011 Tōhoku earthquake, subduction zone earthquakes can cause large tsunamis, and many coastal areas in the region have prepared tsunami evacuation plans in anticipation of a possible future Cascadia earthquake. However, the major nearby cities, notably Seattle, Portland, Vancouver, Victoria, and Tacoma, which are located on inland waterways rather than on the coast, would be sheltered from the full brunt of a tsunami. These cities do have many vulnerable structures, especially bridges and unreinforced brick buildings; consequently, most of the damage to the cities would probably be from the earthquake itself. One expert asserts that buildings in Seattle are vastly inadequate even to withstand an earthquake of the size of the 1906 San Francisco earthquake, much less the much greater one that may well occur.[7]

Recent findings conclude that the Cascadia Subduction zone is more complex and volatile than previously believed. In 2010 geologists predicted a 37 percent chance of an M8.2+ event within 50 years, and a 10 to 15 percent chance that the entire Cascadia Subduction will rupture with an M9+ event within the same time frame. Geologists have also determined the Pacific Northwest is not prepared for such a colossal quake. The tsunami produced could reach heights of 80 to 100 feet (24 to 30 m).

Some other subduction zones have such earthquakes every 100 to 200 years; the longer interval results from slower plate motions. The rate of convergence between the Juan de Fuca Plate and the North American Plate is 60 millimetres (2.4 in) per year.

 Tsunami waves efficiently wrap around islands. All shores are at risk no matter which direction they face. The trough of a tsunami wave may temporarily expose the seafloor but the area will quickly flood again. Extremely strong and unusual nearshore currents can accompany a tsunami. Debris picked up and carried by a tsunami amplifies its destructive power. Simultaneous high tides or high surf can significantly increase the tsunami hazard.  The estimated arrival time in Hawaii of the first tsunami wave is 1028 pm hst sat 27 oct 2012





7.7
Sunday, October 28, 2012 at 03:04:10 UTC
Saturday, October 27, 2012 at 08:04:10 PM at epicenter
52.769°N, 131.927°W
17.5 km (10.9 miles)
QUEEN CHARLOTTE ISLANDS REGION
139 km (86 miles) S of Masset, Canada
202 km (125 miles) SSW of Prince Rupert, Canada
293 km (182 miles) SW of Terrace, Canada
556 km (345 miles) NW of Campbell River, Canada
horizontal +/- 14 km (8.7 miles); depth +/- 4 km (2.5 miles)
NST=716, Nph=716, Dmin=267.2 km, Rmss=0.95 sec, Gp= 58°,
M-type=regional moment magnitude (Mw), Version=A
Magnitude: USGS NEIC (WDCS-D)
Location: USGS NEIC (WDCS-D)
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Sunday, October 28, 2012

The Seven Feasts of Israel



In the Old Testament, God had asked Moses to tell the Israelites that they should celebrate seven feasts to God every year. They are: Turnover, the Feast of Unleavened Bread, Shavuot, Pentecost, the Feast of Trumpets, Day of Atonement and the Feast of Tabernacles.

In the New Testament, in the books of Colossians and Hebrews, Paul mentioned that the Old Testament is the shadow of the New Testament. The festivals that the priests and the Israelites celebrated, no matter whether they are ceremonies, the works of the priests, the offerings, the time of occurrence, the harvests, the weathers, or even the signs on the heaven, they are all presenting all incidents in the New Testament.  

These are a shadow of the things that were to come; the reality, however, is found in Christ.

Hebrews 10:1
The law is only a shadow of the good things that are coming--not the realities themselves. For this reason it can never, by the same sacrifices repeated endlessly year after year, make perfect those who draw near to worship.

Therefore, when we know more about those festivals and the things the Israelites did at that time, we can understand more what Jesus and the church need to do.

For example, in Turnover, it celebrates that a night before the Israelites left Egypt, each family of Israel killed a lamb and used its blood to smear on the doorframe and crossbeam. Therefore, the angels knew that they were Israelites and wouldn’t kill them.

This killed lamb is Jesus. Because he was crucified and his blood can cleanse us, we can get rid of the judgments from God when we believe in God.

Therefore, when John, the Baptist met Jesus, he said, "Look, the Lamb of God, who takes away the sin of the world!

And during the Feast of Unleavened Bread, the Israelites would grind the barley and the wheat into powder form and make the unleavened bread.

Exodus 12:15,
For seven days you are to eat bread made without yeast. On the first day remove the yeast from your houses, for whoever eats anything with yeast in it from the first day through the seventh must be cut off from Israel.

The procedure of these grain would be grinded into powder form represents Jesus would die and injure for us. This was a unleavened bread and represents Jesus died not because he is a sinner, he is sinless and even he was like the unleavened bread and was put into the baker. And Jesus also went to the hell that is full of fire.

During Shavuot, the Israelites would get the firstfruits of the crops and offered them to God. They are olives and grapes. Then Jesus was revived and together with God again, he was the firstfruit and it is represented by Shavuot.

1 Corinthians 15:23,
But each in his own turn: Christ, the firstfruits; then, when he comes, those who belong to him.

And Pentecost is the season of spring rain, also it is the first time of harvest.
Therefore, when the church of New Testament was born during Pentecost, Holy Spirit is dropped like the spring water and to soften people’s heart. It was the big harvest of souls.

Acts 2:17-18; 41
"In the last days, God says, I will pour out my Spirit on all people. Your sons and daughters will prophesy, your young men will see visions, your old men will dream dreams.
Even on my servants, both men and women, I will pour out my Spirit in those days, and they will prophesy.
Those who accepted his message were baptized, and about three thousand were added to their number that day.

And during the Feast of trumpets, two priests would watch the moon. They would blow the trumpets immediately when there was a new moon. They did so to remind the Israelites that it is the Day of Atonement 10 days after. Because it is impossible for the priests to know the exact time of occurrence of the new moon, they only knew it would appear today or tomorrow. Therefore, in the New Testament, Jesus described the time he will come again as “No one knows about that day or hour”. That’s the proper noun of the Feast of Trumpets.

Mark 13:32
"No one knows about that day or hour, not even the angels in heaven, nor the Son, but only the Father.

And on the Day of Atonement, the priest would bring the blood of the live offerings to God in the Most Holy Place. And they would proclaim the name of Jesus that only the priests knew and to look for forgiveness.

Therefore in Acts, Peter said the following:

Acts 2:21
And everyone who calls on the name of the Lord will be saved.'

Therefore, when we are in the age of New Testament, when we know the name of Jesus Christ, we can look for forgiveness by this name.

When we understand more why the Israelites celebrate the festivals to God, we will know more about what Jesus had done for us.

Saturday, October 27, 2012

Authorities warn residents in northern Iceland of threat of large quake, as tremors continue






October 26, 2012 – ICELAND - Icelandic authorities warned people in the north of the island on Thursday to prepare for a possible big earthquake after the biggest tremors in the area for 20 years. The north Atlantic island, where almost 320,000 people live, is a hotspot of volcanic and seismic activity as it straddles a fault in the earth’s surface. The Civil Protection Department said in a statement that recent small quakes in an area under the sea about 20 km (12 miles) off the north of Iceland had prompted it to issue a warning to local people. It said such shocks, one of which was a magnitude 5.6, often led to stronger quakes. Warnings were issued when there were grounds to expect a natural or manmade event that could threaten health and human safety, it added. “People are anxious because they don’t know what might happen,” said Amundi Gunnarsson, chief of the fire brigade in Fjallabyggd, one of the small towns in the area, and a member of the Civil Protection Department. “At the same time, life goes on as usual. People are going to work and children are going to school, but everyone is on alert,” he told Reuters by telephone. The coastal area in the north is home to several small towns and a population of several thousand people. The biggest town in the north of Iceland, Akureyri, has a population of about 17,000 people, and lies roughly 100 km south of the seismic activity. Geologist Benedikt Ofeigsson said houses in Iceland could typically withstand quakes of a magnitude about 7. “Of course there could be some damage to in walls and concrete in such strong earthquakes, but what is important that houses have stood firm,” he told Reuters.


Rapid Changes In Earth’s Core, Magnetic Field And Gravity Seen By Satellites

Annual to decadal changes in the earth’s magnetic field in a region that stretches from the Atlantic to the Indian Ocean have a close relationship with variations of gravity in this area. From this it can be concluded that outer core processes are reflected in gravity data. This is the result presented by a German-French group of geophysicists in the latest issue of PNAS (Proceedings of the National Academy of Sciences of the United States).

Maps of the vertical downward component (sign-changed radial component) of the core magnetic field (A) and its secular variation (B) as estimated at the CMB from the GRIMM-3 model up to spherical harmonic degree 13.




Credit: GFZ/Credit: Mandea et al. www.pnas.org/cgi/doi/10.1073/pnas.1207346109

The main field of the Earth’s magnetic field is generated by flows of liquid iron in the outer core. The Earth’s magnetic field protects us from cosmic radiation particles. Therefore, understanding the processes in the outer core is important to understand the terrestrial shield.

Credit: GFZ/Credit: Mandea et al. www.pnas.org/cgi/doi/10.1073/pnas.1207346109

Key to this are measurements of the geomagnetic field itself. A second, independent access could be represented by the measurement of minute changes in gravity caused by the fact that the flow in the liquid Earth’s core is associated with mass displacements. The research group has now succeeded to provide the first evidence of such a connection of fluctuations in the Earth’s gravity and magnetic field.



Credit: GFZ/Credit: Mandea et al. www.pnas.org/cgi/doi/10.1073/pnas.1207346109

Evolution of the secular acceleration of the vertical downward component of the geomagnetic field computed at the Earth’s surface (as obtained from GRIMM-3 model), which evolves smoothly over the last decade. This animation shows a patch of acceleration migrating from India around 2003 to the southwest of the Indian Ocean in 2008, while a strong patch of deceleration grows in the middle Atlantic to reach a maximum in 2006 and then vanishes rapidly.

Credit: GFZ/Credit: Mandea et al. www.pnas.org/cgi/doi/10.1073/pnas.1207346109

They used magnetic field measurements of the GFZ-satellite CHAMP and extremely accurate measurements of the Earth’s gravity field derived from the GRACE mission, which is also under the auspices of the GFZ. “The main problem was the separation of the individual components of the gravity data from the total signal,” explains Vincent Lesur from the GFZ German Research Centre for Geosciences, who is involved in the study.

Computer simulation of the Earth‘s field in a normal period between reversals. The tubes represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and vertical. The dense clusters of lines are within the Earth’s core


Credit:  Wikipedia

A satellite only measures the total gravity, which consists of the mass fractions of Earth’s body, water and ice on the ground and in the air. To determine the mass redistribution by flows in the outer core, the thus attained share of the total gravity needs to be filtered out. “Similarly, in order to capture the smaller changes in the outer core, the proportion of the magnetic crust and the proportion of the ionosphere and magnetosphere need to be filtered out from the total magnetic field signal measured by the satellite,” Vincent Lesur explains. The data records of the GFZ-satellite missions CHAMP and GRACE enabled this for the first time.

Cutaway of the Earth showing the layers to the core

Credit: Wikipedia

During the investigation, the team focused on an area between the Atlantic and the Indian Ocean, as the determined currents flows were the highest here. Extremely fast changes (so-called magnetic jerks) were observed in the year 2007 at the Earth’s surface. These are an indication for sudden changes of liquid flows in the upper outer core and are important for understanding the magneto-hydrodynamics in the Earth’s core. Using the satellite data, a clear signal of gravity data from the Earth’s core could be received for the first time.

Fig. S2. Spatial and temporal scales of the physical processes causing mass variations in the Earth system. The searched-for core signals, the magnetic jerks, are shown in yellow (adapted from ref. 15).

This results in consequences for the existing conceptual models. Until now, for example, it was assumed that the differences in the density of the molten iron in the earth’s core are not large enough to generate a measurable signal in the earth’s gravitational field. The newly determined mass flows in the upper outer core allow a new approach to Earth’s core hydrodynamics.

Original article:
“Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields”, Mioara Mandea, Isabelle Panet, Vincent Lesur, Olivier de Viron, Michel Diament, and Jean-Louis Le Mouël, PNAS 2012; doi:10.1073/pnas.1207346109