Describe what occurs at plate tectonics with sea floor spreading?
97748
Sea floor spreading is driven by two things. Upwelling magma from beneath the crust erupts at these spreading centers, and pressure and heat from these forms a bulge and magma pushes the plates apart.  Spreading is driven by the mass of the region around the spreading center as it increases and slides off of the bulge pushing outward. At the opposite end of the oceanic plate, there is a pulling motion, caused by colder subducting slabs sinking downward into the asthenosphere. This push-pull motion sets up a gradual motion of the seafloor outward from the mid-ocean ridges. \n\nAnother mechanism that may be contributing to this movement is what is called friction of convection. As plastic nearly-molten rock moves through the mantle is may be dragging these plates along by fricton. Since the spreading centers are likely to be upwellings of deep hot rock, the flow would be moving away from these centers under the ocean crust and pulling it away from the centers.
738049
b) changes\n\nwhen a plate moves it can do a number of things. it can make a mountain, volcano, island, etc.\n\nit doesnt collapse (stupid answer), it wont melt (why would it? all thats happening is a plate moving, that wouldnt melt earth) and it doesnt shrink just because it moves.
745553
Visit my slide show at URL\nhttp://asia.pg.photos.yahoo.com/ph/quake\nMost of the earthquakes occurs at tectonic plate boundaries.\nThis will occur when the accumulated stress (because of the movement of plates ) exceeds the bearable limit of the tectonic plates at that place.
24692
The best answer from the above choices: \nSlow moving convection currents within the molten aesthenosphere supply new material to the spreading centers in the earth's ocean floors and other places. These currents are thought to provide force to cause the motion of the oceanic plates, either directly, or indirectly through the mid ocean ridge building process. \n\nSubduction is only one part of the process of plate tectonics, that does provide some driving force by pulling the subducting plate downward. \n\nGravity has a role as well, as without gravity, the mid-ocean ridges would not have the weight to provide force with which to push the plates apart at the spreading centers, and the subducting plates would not have the force to pull plates. \n\nThe earth's magnetic field may have the least to do with plate tectonics, possibly no role at all.
434745
due to earthquakes formed under sea...
455117
Sea floor spreading is the driving force behind continental drift as it forces the crust apart.  The hot mantle rises to the surface weakening the crust until it splits and moves apart to allow the new material to form.  This rifting creates new oceanic basaltic crust rather than granitic continental crust so the continents stay roughly the same. \n\nHowever, rifting does occur within continents and eventually will split a continent, as is happening in the Red Sea today, the East African Rift being a failed offshoot of that rift system.\n\nAll this happens slowly at a rate of about 11cm a centuary and if you want to see an active spreading ridge take a trip to Iceland where the Mid Atlantic ridge is on surface.  Don't worry it is perfectly safe and you won't end up on the wrong side.
902587
Plate tectonics\nFrom Wikipedia, the free encyclopedia\nJump to: navigation, search\n    \nBridge across the Álfagjá rift valley in southwest Iceland, the boundary of the Eurasian and North American continental tectonic plates.Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology which was developed to explain the observed evidence for large scale motions within the Earth's crust. The theory encompassed and superseded the older theory of continental drift from the first half of the 20th century and the concept of sea floor spreading developed during the 1960s.\n\nThe outermost part of the Earth's interior is made up of two layers: above is the lithosphere, comprising the crust and the rigid uppermost part of the mantle. Below the lithosphere lies the asthenosphere, which is a more viscous zone of the mantle. Although solid, the asthenosphere has very low shear strength and can flow like a liquid on geological time scales. The deeper mantle below the asthenosphere is more rigid again.\n\nThe lithosphere essentially floats on the asthenosphere. The lithosphere has broken up into what are called tectonic plates—in the case of Earth, there are ten major and many minor plates. These plates move in relation to one another at one of three types of plate boundaries: convergent, divergent, and transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The lateral movement of the plates is typically at speeds of several centimetres per year.
481699
The interactions between tectonic plates can cause earthquakes. Plate tectonics is the theory we use to explain how lithospheric or tectonic plates move. For example, two tectonic plates will build up stress (pressure) when their movement is impeded the eventual release of this stress causes an earthquake. There is more material available via Yahoo search. The second source link will help you get a good idea of the plate boundaries.
57504
Earthquakes happen when two tectonic plates grind, scrape, push, or shove up against each other. The harder the collision, the bigger the earthquake. But, if you live in the middle of a tectonic plate, nothing will grind, scrape, push, or shove there so there will be no earthquakes there.
375320
a) Earth's surface is made up of about a dozen enormous slabs, or plates. The slow movement of these plates across the surface is called continental drift, or plate tectonics. \n\nb) the outermost level of the land or sea; "earthquakes originate far below the surface"; "three quarters of the Earth's surface is covered by water" \n\nc) Is a kind of layer  (a relatively thin sheetlike expanse or region lying over or under another )
616929
1) when the plates collide - eg himalayas\n2) when the plates pull apart - eg mid oceanic ridge, it is underwater but still a mountain chain\n3) when one subsides under another, when that plate melts, it can cause a chain of volcanoes, which can also make mountains - pacific rim
855026
Most earthquakes happen along the edge of the oceanic and continental plates. [Oceanic plates are under water, continental plates are above.] The earth's crust (the outer layer of the planet) is made up of a bunch of pieces, called plates. The plates get moved around by the liquid layers of magma underneath the Earth's crust. The plates are always bumping into each other, and pulling away from each other or past eachother. Earthquakes usually happen when two plates are running into each other or sliding past each other. They can also happen along faults, too though.
1096356
Introduction\nPlate tectonics is a relatively new theory that has revolutionized the way geologists think about the Earth. According to the theory, the surface of the Earth is broken into large plates. The size and position of these plates change over time. The edges of these plates, where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes, and mountain building. Plate tectonics is a combination of two earlier ideas, continental drift and sea-floor spreading. Continental drift is the movement of continents over the Earth's surface and in their change in position relative to each other. Sea-floor spreading is the creation of new oceanic crust at mid-ocean ridges and movement of the crust away from the mid-ocean ridges.
383515
In a subduction zone, one plate is being pulled under another. When continental crust & oceanic crust are involved, the oceanic crust is subducted b/c it is denser.\n\nThis type of stress is called compressional stress.\n\nIn the case of ocean ridges, like that found in the middle of the Atlantic Ocean, they are being pulled apart. That is a tensional stress. New crust is constantly being created there.\n\nIn the case of the San Andreas Fault, which is in the news a lot lately, it is two plates that are moving laterally. They are sliding past each other. This is a shearing stress.
669974
Check to following link to know more about Tsunami.\n\nIt's not possible to accurately predict plate tectonics  currently.
133507
The magnetic striping of the seafloor is similiar on both sides of an oceanic rift.  They match up like puzzle pieces.
473257
Try http://www.geo.lsa.umich.edu/~crlb/COURSES/270/Lec12/Lec12.html\nIt helped me do my homework! Also, it has pictures of plate boundries and plate tectonics. Hope it helps!