what forms earth's hard surface?
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The earth's hard surface (commonly called the crust) can be composed of oceanic crust or continental crust.  The two types of crust can form to create plates.  (Refer to plate tectonic theory)\n\nThe creation of the earth's crust can be a result of many processes such as: volcanism (Hawaii/Mt.St. Helens), Rift Zones (Mid-Atlantic Spreading Center), or combinations of the two.\n\nThe boundaries of these plates can convergent (come together), divergent (move apart), or transverse one another (slide past one another). \n\nOne of the most famous boundary between plates is the transverse or strike/slip fault that commonly creates earthquakes in California. The two famous faults are the San Andreas and Hayward faults.  \n\nEarthquakes are simply a build up of forces on these plate boundaries and eventually break.  The "break" is the earthquake  that we feel, the aftershocks can continue after the initial break, but are usually less intense or less strong (see Richter Scale)\n\nTsunamis are the result of deep earthquakes on/or near the ocean floor.  The movement of the fault will move massive amounts of the oceans water table is shifted. This forms a wave that will generate out in all directions.  When the tsunami travels thousands of miles thru the ocean and comes into contact with land it produces large scale waves (anywhere from 20-300+ feet) in height.
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In Geology Fractures in bedrock are structure of a specific region of the earth's crust. A crack or fault in a rock.The solid rock that underlies loose material, such as soil, sand, clay, or gravel. The very basis; the foundation. The lowest point.In Geology a fracture in the continuity of a rock formation caused by a shifting or dislodging of the earth's crust, in which adjacent surfaces are differentially displaced parallel to the plane of fracture. Also called shift.  There are many fault lines across the United States
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About 1,800 miles beneath the surface, Earth's internal structure changes abruptly where the solid rock of the mantle meets the swirling molten iron of the outer core. \nBut the boundary between the core and the mantle may not be as sharply defined as scientists once thought. By analyzing earthquake waves that bounce off the core-mantle boundary, researchers have found evidence of a thin zone where the outermost core is more solid than fluid.\n\nThe existence of such "core-rigidity zones" -- small patches of rigid material within the fluid outer core -- has been suggested before, but this report marks the first time scientists have detected one.
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The outer crust of the earth is made up of sections of crust.  These sections are called tectonic plates and they float on the magma (lava) below.  When the plates shift, the friction between them causes earthquakes.
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The 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.
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Magma, or molten rock located beneath the earth's surface, cools upon reaching the surface to form the crust. This crust is moved away from the location of upwelling by thermal convection currents in the semi-plastic mantle. The crust is then resorbed back into the mantle upon meeting another, less dense (more buoyant) crust. \n\nThere are two types of crust: oceanic and continental. Each are made from different minerals, resulting in oceanic crust being 'heavier' (denser) and thus sinking below the 'lighter' (less dense) continental crust at convergent boundaries. The earth's crust is in a state of constant motion (or, in some places, no motion, but a building up of energy) called plate tectonics. \n\nSee the wikipedia link below for more details. Hope that helped.
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it's the core of the earth. lava. melted rock.etc
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go to\nhttp://en.wikipedia.org/wiki/Earth
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Minerals are what make up rocks.  When Earth's rocks erode, these minerals are released.  A lot of times, erosion takes place in higher elevation areas because the denudation (erosion) rate of higher elevations is also higher than lower elevations and streams usually stem from places of higher elevation.  Minerals then are deposited into these streams.
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The earth has four layers...\n\nTheCrust, Upper mantle, Lower Mantle and the Core refer to <http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers1.html>\n\nThe Crust has many hollow parts like caves. Caves connected to the ocean and some undergorund river, near an instict volcano is posible of supporting life.\n\nHumans can live there but not making civilization. Just hiding from dangers on the surface such as crusaders, barbarians, dinasours, wild animals...at the present these caverns is used for safety hiding places from war, nuclear attack and for the one of the most dangerous speicies on earth and that is the Humosapiens.....
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The earth is APPROXIMATELY round due to gravitational forces.
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Earth: \nthe fragmental material composing part of the surface of the globe; especially: cultivable soil; or\nareas of land as distinguished from sea and air; or\nthe planet on which we live that is third in order from the sun.\n\nIt depends how you use it, really...
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Probably silicone and iron.   It's a friggin big rock.   Hollow it out a bit; near the center the gravity is probably near earths gravity.
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*\nGetting to the Core\nDon't believe Jules Verne. The center of the Earth is not a nice place to visit, unless you like hanging out in a blast furnace. The outer core of the Earth, about two-thirds of the way to the center, is molten iron. Deeper yet, at the inner core, the pressure is so great -- 3.5 million times surface pressure -- that iron solidifies, even though the temperature is believed to exceed 11,000 degrees Fahrenheit, hotter than the surface of the sun.\n\nDespite rapid advances in high-pressure laboratory techniques, it's not yet possible to duplicate these conditions experimentally, and until Stixrude and Cohen's work, scientists could at best make educated guesses about iron's atom-to-atom architecture -- its crystal structure -- at the extremes that prevail in the inner core. Using a quantum-based approach called density-functional theory, Stixrude and Cohen set out to do better than an educated guess. With recent improvements in numerical techniques, density-functional theory had predicted iron's properties at low pressure with high accuracy, leading the researchers to believe that with supercomputing they could, in effect, reach 3,000 miles down into the inner core and pull out what they needed.\n\n\nCRYSTAL AT THE CENTER OF THE EARTH: Anisotropy of Earth's Inner Core  [New Window] \nThere's a giant crystal buried deep within the Earth, at the very center, ... The center of the Earth is not a nice place to visit, unless you like hanging ...\nhttp://www.psc.edu/science/Cohen_Stix/cohen_stix.html
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lithosphere is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost layer of the mantle (the upper mantle or lower lithosphere) which is joined to the crust. for more see http://en.wikipedia.org/wiki/Lithosphere..\n\nAsthenosphere is the region of the Earth between 100-200 km below the surface — but perhaps extending as deep as 400 km — that is the weak or "soft" zone in the upper mantle. It lies just below the lithosphere, which is involved in plate movements and isostatic adjustments. In spite of its heat, pressures keep it plastic, and it has a relatively low density. Seismic waves, the speed of which decrease with the softness of a medium, pass relatively slowly though the asthenosphere, the cue that originally alerted seismologists to its presence; thus it has been given the name low-velocity zone. for more see http://en.wikipedia.org/wiki/Asthenosphere ..
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Most igneous rock is formed deep in the earth where it is very hot.  Igneous means fire, similar to ignition which fires a spark plug in an engine.  Igneous rock may be formed at or near the surface of the earth when volcanoes erupt and lava flows.  The rock closest to the lava heats up most and becomes more igneous than rock further and further away.  There is usually a clear change in coloration of the affected rock because its crystal minerals are altered by the heat.  Lava can flow following existing cracks in rocks and partially transform the adjacent rock to igneous foorms as it cools.
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The Earth is not a perfect sphere so you are at different distances from the centre at different places.\nThe density of the Earth is not constant so above dense rocks you appear slightly heavier.\nThe Earth spins so at the equator you are lifted slightly by the Eotovos effect.