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It is called "antipodal focusing". See for example Antipodal focusing of seismic waves observed with the USArray. We present an analysis of the M-w = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in ...


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Ocean waves (and also in mediterranean type seas and larger lakes, but on a smaller scale) are generated by two processes: locally generated waves ("wind waves"), which follow the direction of the wind; waves generated further out in the sea (i.e. "swell waves"), which do not necessarily follow the direction of the wind. During the night, you are probably ...


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The idea discussed in the paper you reference is about transferability of Mohs ordinal scale to true hardness. A mineral's ability to scratch is related to it's hardness, but only an indentation test measures absolute hardness (e.g. the Vickers scale). Mineral orientation relative to planar structure can change the result in a scratch test, and two minerals ...


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It may be difficult to ascertain the hardness of a mineral relative to an other mineral in a Mohs streak test if one (or both) are not homogeneous. Already a small local grain of an impurity may put you off; you might remember the occasions of the sudden scratching sound of chalk on the green board. Which is why pen-shaped hardness picks are advantageous: ...


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Wind blows from sea to land in day and land to sea in night due to pressure and temperature difference. Not so much. This is common in the Mediterranean in summer, for example, where the area sits under a stable area of high pressure and there is little wind caused by the weather system. Go to the Med in winter though, and you'll find the weather systems ...


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I'm making my comment an answer. Waves are ubiquitous, except on land ;-). Waves in the open sea are a mix — a superposition — of waves in different directions.1 The dominating direction of large waves is, after a while, the wind direction; but that's not absolute. You have some omnidirectional background "noise" of chaotic movement as well as ...


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