Science fair reminder!

Material list and procedures are due this Friday.  Science journals will be checked as well.

Plate Tectonics

Moving and Shaking
from National Geographic

There are a few handfuls of major plates and dozens of smaller, or minor, plates. Six of the majors are named for the continents embedded within them, such as the North American, African, and Antarctic plates. Though smaller in size, the minors are no less important when it comes to shaping the Earth. The tiny Juan de Fuca plate is largely responsible for the volcanoes that dot the Pacific Northwest of the United States.

The plates make up Earth's outer shell, called the lithosphere. (This includes the crust and uppermost part of the mantle.) Churning currents in the molten rocks below propel them along like a jumble of conveyor belts in disrepair. Most geologic activity stems from the interplay where the plates meet or divide.

The movement of the plates creates three types of tectonic boundaries: convergent, where plates move into one another; divergent, where plates move apart; and transform, where plates move sideways in relation to each other.

Convergent Boundaries

Where plates serving landmasses collide, the crust crumples and buckles into mountain ranges. India and Asia crashed about 55 million years ago, slowly giving rise to the Himalaya, the highest mountain system on Earth. As the mash-up continues, the mountains get higher. Mount Everest, the highest point on Earth, may be a tiny bit taller tomorrow than it is today.

These convergent boundaries also occur where a plate of ocean dives, in a process called subduction, under a landmass. As the overlying plate lifts up, it also forms mountain ranges. In addition, the diving plate melts and is often spewed out in volcanic eruptions such as those that formed some of the mountains in the Andes of South America.

At ocean-ocean convergences, one plate usually dives beneath the other, forming deep trenches like the Mariana Trench in the North Pacific Ocean, the deepest point on Earth. These types of collisions can also lead to underwater volcanoes that eventually build up into island arcs like Japan.

Divergent Boundaries

At divergent boundaries in the oceans, magma from deep in the Earth's mantle rises toward the surface and pushes apart two or more plates. Mountains and volcanoes rise along the seam. The process renews the ocean floor and widens the giant basins. A single mid-ocean ridge system connects the world's oceans, making the ridge the longest mountain range in the world.

On land, giant troughs such as the Great Rift Valley in Africa form where plates are tugged apart. If the plates there continue to diverge, millions of years from now eastern Africa will split from the continent to form a new landmass. A mid-ocean ridge would then mark the boundary between the plates.

Transform Boundaries

The San Andreas Fault in California is an example of a transform boundary, where two plates grind past each other along what are called strike-slip faults. These boundaries don't produce spectacular features like mountains or oceans, but the halting motion often triggers large earthquakes, such as the 1906 one that devastated San Francisco.

A Visual Approach to Understanding Tectonic Plates

Teaching Plate Tectonics with Easy-to-Draw Illustrations - Geology.com

Our Earth is constantly changing....recent events have demonstrated this quite well. Understanding how these destructive and constructive events take place is sometimes hard to grasp, but they tell us a lot about the composition of the planet we live on. The link attached above is a good reference and goes along with the illustrations we will be using in class. Feel free to take a gander if you have missed class, or if you didn't quite understand something in class.

Angry squirrel terrorizes Vermont town

Angry squirrel terrorizes Vermont town
Just some randomness for your Thursday afternoon.

REMINDER

TEST TOMORROW!!!!!!!!! BE SURE TO GET YOUR STUDY GUIDE SIGNED BY A PARENT!!!!


Check out this article from the Wall Street Journal about the recent Earthquake in Japan.

Earth's Energy Unleashed as Tectonic Plates Shift

By GAUTAM NAIK

Reuters

The tsunami washes inland Friday in coastal areas of Iwanuma, Miyagi prefecture, in northeastern Japan.

Even in Japan's turbulent seismic history, the 8.9-magnitude earthquake that struck Friday was one for the record books.

The quake—the fifth-largest recorded since 1900 and the biggest to hit Japan in three centuries—released almost 1,000 times the energy released in the Haiti quake a year ago. Friday's quake also triggered a tsunami that traversed the planet, all the way to the shores of California.

Seismologists at the Lamont-Doherty Earth Observatory in Palisades, N.Y., talk with WSJ's Christina Tsuei about the science behind Japan's devastating earthquake.

Tsunami-causing quakes usually occur where shards of the earth's crust—tectonic plates—meet. Magma rises from deep inside the Earth, causing the plates to move. They slide past each other but sometimes get stuck. When they jerk forward again, they can trigger a quake.

Friday's quake occurred where the Pacific plate, moving at a speed of about three inches a year, slides under the Eurasian plate. The last big quake there occurred in 1933, causing 3,000 deaths. Since then, the plates have been trying to move past each other, but have been jammed in place.

On Friday, the accumulated strain overcame the strength of the rocks deep beneath the sea some 80 miles offshore. "The rocks cracked under the pressure," causing the plates to jerk forward again, said John Elliott, an earthquake geophysicist at the Centre for the Observation and Modelling of Earthquakes and Tectonics at Oxford University in England.

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The jerking motion of one plate moving under the other caused a massive uplift of the seafloor, convulsing an area almost 200 miles long and 50 miles wide.

"It's hard to even imagine just how much water was displaced," said Lynda Lastowka, seismologist at the United States Geological Survey.

The resulting 30-foot-tall tsunami slammed into Japan's northern coast and swept away people cars, boats and buildings.

A 30-foot-high tsunami brought catastrophe to cities and towns up and down 1,300 miles of Japan's northern coastline. WSJ's Jason Bellini maps out the city-by-city devastation.

The tsunami traveled across the Pacific at about 550 miles per hour, or the speed of a jet plane. Its undulations likely passed unnoticed on most ships, because the crests tend to be less than three feet tall and are hundreds of miles apart.

A system known as Deep Ocean Assessment and Reporting of Tsunamis, or DART, picked up the signals and allowed officials to issue tsunami warnings reaching across the Pacific Ocean.

DART, developed by the U.S. National Oceanic and Atmospheric Administration, consists of spheres moored to the deep ocean floor that use pressure gauges to measure the variation in sea levels. Data from a tsunami wave passing overhead are sent to a buoy on the sea surface, which zaps the information via satellite to monitoring stations in Hawaii and elsewhere.

The awesome force of a tsunami only becomes apparent in shallow water. As it approaches the coast, the wave slows down to about 20 to 30 miles an hour. By then, all its energy is packed into much less depth, which can increase the wave's height dramatically.

Though Friday's tsunami caused tremendous devastation in northern Japan, its impact elsewhere appears to have been modest. Waves as tall as 5.7 feet were reported at a harbor in Hawaii, while some parts of central California saw waves as high as 6.2 feet, according the USGS.

The tsunami unleashed by the 2004 Indonesian quake was far more destructive to far-off places than the tsunami generated near Japan. The 2004 temblor was bigger—9.1 magnitude—and released far more energy. In addition, the 2004 wave had to travel only 800 miles before it reached Sri Lanka, one of the hardest-hit countries. By comparison, the Japan tsunami traveled about 3,500 miles to reach Hawaii, which dissipated a good amount of its energy.

Tomorrow's Open Reponse---HINT HINT!

Today it pays off to check out the class blog. Tomorrow's open response will be over the rock cycle. Be sure you know all three types of rock, how they form, and how a rock can change into a different type of rock. A nice diagram would be the chart we filled out during our "Crayon Rock" lab. Good luck and keep coming back for more class news and science facts.

Science Fair

We are well on our way to another successful year of Science Fair Projects. Research Papers are coming in and looking GREAT!! Just a reminder...that you should be writing in your lab journal when you work on your project.

The next task for you to complete is to construct a hypothesis. Check out these links for help!

• Variables
• Variables for Beginners
• Hypothesis

You are now getting to the fun part of the Science Fair. The information you gathered while writing your research paper will now help you set up a FAIR TEST and develop a well-thought hypothesis.

Upcoming Important Dates

• Mineral and Rock OR: Tuesday, March 15
• Mineral and Rock Test: Wednesday, March 16
• Variables and Hypothesis Worksheet; Friday, March 18
• Material List and Experimental Procedure; Friday, March 25