If an asteroid hit the earth it would most likely hit the ocean
Nick Strobel 2010 (June 4, http://www.astronomynotes.com/solfluf/s5.htm, PhD -- Astronomy -- University of Washington,)
The oceans cover about 75% of the Earth's surface, so it is likely the asteroid will hit an ocean. The amount of water in the ocean is nowhere near large enough to "cushion" the asteroid. The asteroid will push the water aside and hit the ocean floor to create a large crater. The water pushed aside will form a huge tidal wave, a tsunami. The tidal wave height in meters = (distance from impact)-0.717 × (energy of impact)0.495/ (1010.17). What this means is that a 10-km asteroid hitting any deep point in the Pacific (the largest ocean) produces a megatsunami along the entire Pacific Rim
Asteroid Detection Mining
Once an asteroid is detected it can be placed into high Earth orbit using mass drivers and mined for recourses.
Space Studies Institute No Date [Institute committed to completing the missing technological links to make possible the productive use of the abundant resources in space, Space Studies Institute, “Asteroid Deflection,” No Date, SM, Accessed: 7/11/11, http://ssi.org/reading/papers/asteroid-deflection/]
SSI funded studies of asteroid detection, asteroid tracking, and mining of asteroids. We also studied the concept of assembling a mass driver engine in orbit, sending it to an Earth-approaching asteroid, and then using the mass driver to modify the asteroid’s orbit. This research was conducted with the goal of guiding the asteroid into a High Earth Orbit where it could be mined for its minerals. But such a technological capability, once developed, has obvious applications should we ever need to divert an asteroid from an Earth-intercepting course. For a long while, the conventional wisdom on this issue was that one would use nuclear explosives for this purpose. But according to a paper published in the June 4th, 1998 issue of Nature, this may not be as easy as previously thought. It points out that many asteroids are multi-lobed. A nuclear detonation might be largely absorbed by one lobe, with little course deflection resulting in the whole. The paper theorizes that the average asteroid may not be so much like a solid rock as an aggregate of fragments loosely held together by fine dust. If this “flying gravel pile” theory is correct, a nuclear detonation might pulverize an approaching asteroid, converting one big problem into many little ones. A mass driver engine, by contrast, could provide the low, steady, continuous thrust needed to change an asteroid’s course gradually, using the asteroid’s own material for reaction mass. The ability to modify an asteroid’s course via mass driver certainly promises to usher in a new era where space resources are freely available for construction projects in High Earth Orbit, and holds out promise for obtaining resources in a way which is not damaging to the environment of Earth. But it is just barely conceivable that this same technology might also help to avert a catastrophe of major proportions. In any event, a major program of asteroid mining can only make the Earth safer as the centuries pass. As it happens, those asteroids which cross the orbit of the Earth (and thus pose the greatest hazard) are also the ones most economically attractive for space-resource use.It is good that humanity is becoming more aware of the threat posed by Earth-crossing asteroids. But at the same time we should also become more aware of their vast economic potential.
Asteroid Detection is a vital first step to mining them
Crandall, Gorman, and Howard 11 (William- MBA Founder Space Wealth BC, Larry- Professor of Finance Cal Poly and Peter-Ph. D Senior Scientist Exelixis Inc, “Is Profitable Asteroid Mining A Pragmatic Goal?”, Space Wealth, 23 February 2011, http://spacewealth.org/files/Is-P@M-Pragmatic-2011-02-23.pdf, CGW)
Platinum group metals are abundant in certain types of near Earth asteroids (NEAs). NEAs that are mineralogically similar to one of the most common types of “observed fall” meteorites offer PGM concentrations (4.5 ppm) 30 that are comparable to those found in profitable terrestrial mines (36 ppm). Other meteorites suggest that some asteroids may contain much more valuable metal. 32 The PGM value of a 200 m asteroid can exceed $1 billion, or possibly $25 billion. Over 7,500 NEAs have been detected. Close to a fifth of these are easier to reach than the moon; more than a fifth of those are ≥200 m in diameter: 200+ targets. President Obama requested, and Congress has authorized, a fourfold increase in detection funding ($5.8 m to $20.4 m/year). 36 This could lead to ~10,000 known 200 m NEAs in a decade. Detection is just a start.The costs to locate, extract, and process asteroid ore are not well understood. Before significant private capital is put at risk, we need to learn more. In cooperation with other forward looking nations, the U.S. should purchase an option to develop asteroid resources by investing in the knowledge required to mine asteroids. We can then choose to exercise this option if terrestrial PGM supplies do in fact collapse. Asteroids may also be able to supply other metals that are increasingly at risk. There are several candidates: In 2009, the U.S. imported 100% of 19 key industrial metals. To seek the “fullest commercial use of space,” NASA should buy down the risk of asteroid mining ventures by investing in R&D that can give us the tools to discover, analyze, and process asteroid ore, and deliver it safely to Earth, and to Earth orbit. NASA, with other space agencies, should run demonstrations for this globally important program so that, as the GAO likes to put it, useful “knowledge supplants risk over time.”