On 19 Mar 2011, an enormous crack, measuring 100 meters wide
and three kilometers long, appeared in the Huacullani district in the Chucuito
province, department of Puno. This crack determined Peru's geophysical
institute to rule out the occurrence of an earthquake in the area. Another
crack in the Earth's crust being located in the Afar region of Ethiopia was
open in just a few days in 2005, a study suggested. The crack can be the
forerunner to a new ocean. This crack is the surface component of a continental
rift forming as the Arabian and African plates drift away from one another. It
began to open up in September 2005, when Dabbahu volcano erupted. The magma
inside the volcano couldn't reach the surface and erupted as a fountain of lava
– instead, it was diverted into the continental rift underground. The magma
cooled into a wedge-shaped "dike" that was then uplifted, rupturing
the surface and creating a 500-metre-long, 60-metre-deep crack. Similar dikes
around 10 kilometers long and 1 meter wide also appeared in Iceland. Some
studies show that the formation of dikes can occur in large segments and over
much shorter periods than previously thought. "At some point, if that spreading and
rifting continues, then that area will be flooded," says Ken Macdonald, a
marine geophysicist at the University of California, Santa Barbara. Icelanders
were surprised when a large lake began to disappear into a long fissure created
by one of last summer's earthquakes on September 2001, Bijal P. Trivedi for
National Geographic declared. A geologist noticed a large gash in the landscape
about 20 kilometers (13 miles) from Reykjavik.
The fissure having a foot wide and 400 meters (1,280 feet) long led
straightly into Lake Kleifarvatn, so this lake has shrunk dramatically. ''Summerhouses
that were once mere steps from waterfront are now more than a kilometer away
from the water's edge'', Clifton said. "I couldn't find an earthquake in our
database that was big enough to cause such a huge rupture in the surface,"
said Clifton. Clifton tried to understand the relationship between the movement
of faults deep within Earth and their surface effects in the area. A giant,
deep and narrow crack was open in the ground of Seagi Gulistan, Pakistan on 7
March 2011. A large crack also appeared after a strange earthquake in Menominee
Township of Michigan, US, but no one really knows why such a massive crack
appeared thinking that there is no fault line in that zone. A crack over two kilometers
long and up to a meter deep has been discovered on the Baltic island of
Hiddensee on Jan 2012. Large zones of the German island’s coastline have been
blocked off amid fears of a big landslide. Authorities from the Western
Pomerania Lagoon Area national park have warned that the fracture line has been
widening, with smaller cracks developing off the main fault measuring up to 10 centimeters
wide. “We are preparing for a catastrophe,” park official Frank Martitz told
the Bild daily. The island measuring 3.7 kilometers at its widest point and 205
meters at its narrowest point is a destination for tourists.
There were two gigantic earth changing events in Mexico in
two weeks .A huge crack was open in Dolores Hidalgo, Guanajuato. Land sank in
Venustiano Carranza.Dolores Hidalgo, Guanajuato and Venustiano Carranza fall in
a right line from one another on the map. Similar cracks have formed recently
in 2012 in Spain, Peru, and other areas around the world. On July 1, 2012, a
huge crack was open in the earth between La Grulla and La Joya. The earth crack
is around 13 ft. (4 m) wide, 196 ft. (60 m) deep, and 9 miles (15 km) long.
Another hole was open to one side of the crack being so deep that the bottom
could not be seen. The communities of Jamaica, Fátima, The Crane and The Jewel
had to be isolated. Louisiana sinkhole also grows. (September, 2012)
Drastic fluctuations in ice accumulations were reported at both
poles on September, 2012. Coalition chairman, Hon Barry Brill, said the most
important aspect is the extent exceeds the usual Antarctica averages. “The sea
ice cover yesterday was 311,000 square kilometers above the 1979-2012 average.
The surplus ice is more than twice the area of New Zealand.” he said. “Over the
33-year period aggregate global sea ice volumes have remained steady, but there
are fluctuations between the two polar areas from year to year. The
fluctuations are the result of ocean currents and wind patterns, rather than
temperatures. Antarctic ice is much more important than that of the Arctic. The
area of its sea ice is a million square kilometers larger than the highest
value ever recorded in the Arctic. Then, of course, the Antarctic is an entire
continent, with more than 90% of the earth’s glacial ice,” Mr. Brill also
declared. '' The cap of the Antarctic is increasing in thickness in most
places, except around the Antarctic Peninsula. Sea ice extent is largely a
consequence of sea surface temperature, ocean currents and wind,” the chairman
concluded. New sea ice is finally starting to form again in the Arctic, scientists
reported. Mark Serreze, director of the National Snow and Ice Data Center, said
in a statement ,“While we’ve long known that as the planet warms up, changes
would be seen first and be most pronounced in the Arctic,” –MSNBC.
Because of the pressure under Japan’s Mt. Fuji volcano rising,
this eruption would be nightmare for Japan people being on Japanese soil at the
time the earthquake-tsunami would hit, on September 7, 2012, officials said.
Earth was cracking up under Indian Ocean. On 11 April 2012,
as Earth's crust began to break the tectonic plate. Two gigantic earthquakes
ripped through the floor of the Indian Ocean triggering large aftershocks on
faults of the world and providing the evidence that the Indo-Australian plate
is being torn in two parts, Colin Barras wrote in a magazine on 26 September
2012. Twin quakes having the magnitude 8.6 and 8.2 took place off the coast of
North Sumatra, geologists declared. These quakes usually occur at the boundary
between tectonic plates, where one chunk of Earth's crust slides beneath another.
These quakes took place at more than 100 kilometers from the subduction zone.
''Both involved rocks grinding past each other sideways with very little
vertical movement - what geologists call strike-slip earthquakes. Yet
strike-slip quakes this large had never been reported before.'', geologists
also said. Matthias Delescluse at the École Normale Supérieure in Paris,
France, and his colleagues have analyzed quakes in the zone since December
2004, when a magnitude-9.1 quake in a subduction zone near Sumatra triggered a
huge tsunami. They concluded that the earthquakes occurring this period were
nearly ten times more frequent compared with the previous 8 years, involving
rocks, which were pushed and pulled in the same directions. ‘The Indo-Australian
plate is breaking up along a new plate boundary'', said the researchers.
Although both are on the same plate, Australia is moving faster than India.
''This is causing a broad area in the center of the Indo-Australian plate to
buckle. As a result, the plate may be splitting.'' the same researchers declared.
“I think it's a fair argument that the 11 April earthquakes may mark the birth
of a plate boundary," Lingsen Meng at the University of California,
Berkeley, declared.
A huge crack is also open in Antarctica. The Pine Island
Glacier's vast crack was pictured via NASA satellite the late last fall. ''With
a gargantuan crack slowly splitting it apart, Antarctica's fastest-melting
glacier is about to lose a chunk of ice larger than all of New York City,
scientists say.''-Richard A. Lovett at
National Geographic News noted on
February 2, 2012 .A Manhattan-size ice island also cracked in two parts.
''Snaking across the floating tongue of the Pine Island Glacier in West
Antarctica, the crack is expected to create an iceberg 350 square miles (907
square kilometers)''- according to NASA. ''Usually there's nothing
extraordinary about a glacier calving,'' declared glaciologist Ted Scambos of
the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.''Glaciers
that flow into the sea, like the Pine Island Glacier, go through a normal cycle
in which the floating section grows, stresses mount, and an iceberg breaks off,
''Scambos said. ‘But when the pattern deviates, glaciologists take notice. In
this case, the crack is forming significantly farther upstream than has
previously been the case. That signifies that there are changes in the
ice," he declared. The ice will flow into the ocean at a faster rate, determining
the sea level to rise. ''As far as sea levels are concerned, changes in the
Pine Island Glacier and other West Antarctic glaciers are far more important
than shifts among the continent's other glaciers, such as East Antarctica's
Mertz Glacier'', declared oceanographer
Doug Martinson of Columbia University's Lamont-Doherty Earth Observatory.
Knowing that the
oceanic crust is basalt, scientists declared that molten rock had been added to
the ridge as the ridge pulled apart at the center. The rock erupting under the
sea lava cools in the crack of the splitting ridge. The oceanic crust is made
up of long strips of caulking taking on the magnetic polarity of the earth's field.
When the floor moves away from the ridges, the striped pattern of magnetic
variation ends rather abruptly against the continents .Sometimes, the
distribution of earthquakes is deep beneath the margins of the continents. The
plates of the oceanic crust are moving down beneath the continental plates. The
zone between the ridge and the continental margin is one plate, and the
continent is another plate. The magnetic pattern off the coast of Washington
suggests that much of the Pacific oceanic crust plunged beneath the North
American continent. (Guide to the Geology of Olympic National Park by Rowland
W. Tabor, of the USGS)
The earth has three concentric zones: the crust, the mantle
and the core. The core can be divided into two regions: a solid inner core and
a liquid outer core containing metallic iron .The crust floats upon the mantle
in two forms: the continental crust and the oceanic crust. The thick continental crust has deep buoyant
roots that help to support its elevations above.
Near the top of the mantle is a region of partially melted
rock called the asthenosphere. The hot magma rises and the cool magma sinks due
to differences in density. The layer of the mantle above the asthenosphere and
the entire crust form the lithosphere. The lithosphere is broken into plates that
“float" upon the asthenosphere being in constant motion. A convergent
plate boundary occurs when two plates collide. If this involves two continental
plates, the crust is compressed into high mountain ranges such as the
Himalayas. If an oceanic plate and a continental plate collide, the oceanic crust
is sub ducted under the continental crust and usually results in a deep ocean
trench such as the "Mariana Trench" in the Pacific Ocean. The sub
ducted crust melts and rises to the surface to form a volcano. A divergent
plate boundary occurs when two plates move away from each other. Magma
upwelling from the mantle region is forced through the resulting cracks to form
a new crust. The mid-ocean ridge in the Atlantic Ocean is a zone, where new
crustal material forms as plates diverge. Volcanoes can also occur at divergent
boundaries. The island of Iceland is an example. A third type of plate boundary
is the transform boundary occurring when two plates slide past one another
triggering earthquake. The San Andreas Fault in California is an example of a
transform plate boundary. An active volcano occurs when magma reaches the
earth's surface through a crack or vent in the crust determining the extrusion
of lava, the ejection of solid rock, the ejection of ash, and the release of
water vapor or gas. Volcanoes occur near plate boundaries, 80 percent at the
convergent plate boundaries. The Cascade Range was formed in this way. An
earthquake occurs when built up strain in rock mass causes a rupture below the
surface of the crust. Earthquakes
generally occur along breaks in the rock mass known as faults. Some 80 percent
of all earthquakes occur near convergent plate boundaries. Earthquakes are also
often associated with volcanic activity due to the movement of sub-surface
magma. When an earthquake occurs under the ocean, it can trigger a destructive
tidal wave known as a tsunami. Rocks can be classified into three groups:
igneous, sedimentary, and metamorphic. Igneous rocks, like granite and basalt,
form when magma cools and crystallizes subsurface and on the surface.
.Sedimentary rocks are formed by the consolidation of the weathered fragments
of pre-existing rocks as a result of erosion and transport by wind, water or
ice, followed by sediments. The process of compaction and cementation is known
as lithification. Metamorphic rocks are formed when solid igneous or
sedimentary rocks change in response to elevated temperature, pressure and
chemically active fluids. Marble is a metamorphosed form of limestone.
Anthracite is a metamorphic form of coal. Soil formation begins with
unconsolidated materials that are the products of weathering. The weathering process involves the
disintegration and decomposition of the rock. (University of California College
Prep)
''Scientists claim that Earth is not expanding Since
Darwin’s time; scientists have speculated the planet might be expanding or
contracting. Even with the acceptance of plate tectonics half a century ago,
which explained the large-scale motions of Earth’s outermost shell, the
accusations persisted; some Earth and space scientists continued to speculate
on Earth’s possible expansion or contraction on various scientific
grounds.''-CHILLYMANJARO – SEPTEMBER 30, 2012
My question is- Does the earth crust crack because of losing
lava, this missing making earth’s nucleus be smaller than before? The answer is,’’
Magma sometimes rises under enormous pressure, so it not only finds cracks in
the earth’s crust, it can also create them.’’
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