Where the rainbow fringes become most tightly spaced is where the fault break came closest to the surface, although the data indicates the fault is unlikely to have broken right through to the surface.

BBC: Christchurch quake mapped from space

Starting with two silicon wafers, Soitec machines coat the surface of one with silicon dioxide insulator and embed inside it a thin fault line of hydrogen atoms anywhere from 100 to 20, 000 nanometers below the surface, depending on customers' desired wafer thickness.

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