The painstaking search for missing flight MH370 has uncovered a previously unknown undersea world of volcanoes, deep valleys and soaring ridges, according to detailed maps released by Australia. Although no trace of the Malaysia Airlines plane was found during the search in the southern Indian Ocean -- the most expensive ever of its kind -- large volumes of data showing a detailed picture of the sea floor had to be collected to guide the probe. "It is estimated that only 10 to 15 percent of the world's oceans have been surveyed with the kind of technology used in the search for MH370," Geoscience Australia's environmental geoscience chief Stuart Minchin said late Wednesday.