Word: seismic
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Dates: during 1950-1959
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...Weather Bureau last week. Back from 15 months with the Russians at Mirny on the Indian Ocean coast of Antarctica, Rubin revealed that a Russian party trekked about 1,500 miles inland to the "pole of inaccessibility," setting off dynamite charges in the ice to make seismic soundings every 30-50 miles. Echoes showed continuous land instead of a complex of islands or submerged mountains. The Russians say the land ranges from 2,500 to 12,000 ft. above sea level, with ice up to 3,000 ft. thick covering the high points...
...Geneva last summer concluded that a worldwide system of 180 inspection stations could detect nearly all underground nuclear tests. Any explosion of even the modest energy of 5 kilotons, they figured, could be distinguished from the noise made by small earthquakes and other natural causes. Only about 100 seismic "events" a year would be borderline cases. These could be followed up and checked by other means...
...weeks ago the U.S. Government announced that new information has cast doubt on the effectiveness of the 180-station system. Last week the U.S. Department of Defense released the data that led to this conclusion. To measure the seismic effects of underground tests, 16 special seismographs were set up in a line extending from the Nevada atomic proving ground to Maine, 2.500 miles away...
...right, but not quite as strongly as had been anticipated. At distances above 700 miles, only explosions of more than 20 kilotons could be identified clearly as manmade. To sum up, said the panel, the 180-station detection system might be confronted by 1,500, not 100, natural seismic shocks a year that could not be distinguished from an underground test explosion. This number would presumably overburden the checking system as presently outlined...
...strength of results of a single 1957 test, President Eisenhower's Science Advisory Committee estimated that underground atomic blasts down to five kilotons could be fully detected by seismic inspection stations. On the basis of the five-kiloton report, the U.S. settled down with the Russians at Geneva to try to negotiate a stop-tests agreement with an inspection and detection system-but fully aware that the chances of detection were slim below the five-kiloton underground threshold...