Greenland glacial quakes becoming more common.The number of earthquakes that occur beneath surging glaciers This is a list of glaciers. Due to somewhat sparse information, some glaciers, especially those in the tropics, may no longer exist as listed. This is especially true for glaciers in Africa and New Guinea. in Greenland Greenland, Green. Kalaallit Nunaat, Dan. Grønland, the largest island in the world (2005 est. pop. 56,000), 836,109 sq mi (2,166,086 sq km), self-governing overseas administrative division of Denmark, lying largely within the Arctic Circle. has doubled in the past 4 years, another possible effect of the melting ice sheet there. Just 2 years ago, scientists reported a newly recognized phenomenon: earthquakes occurring beneath glaciers, probably from sudden slips of those ice masses (SN: 1/3/04, p. 14). The magnitudes of those quakes, which aren't aren't Contraction of are not. See Usage Note at ain't. aren't are not aren't be associated with known faults, measure between 4.6 and 5.1, says Goran Ekstrom, a geophysicist ge·o·phys·ics n. (used with a sing. verb) The physics of the earth and its environment, including the physics of fields such as meteorology, oceanography, and seismology. at Harvard University Harvard University, mainly at Cambridge, Mass., including Harvard College, the oldest American college. Harvard College Harvard College, originally for men, was founded in 1636 with a grant from the General Court of the Massachusetts Bay Colony. : Seismic data gathered from 1993 to late 2005 identify. 136 quakes along the southeastern and southwestern coasts of Greenland, all of them originating beneath glaciers that flow at the fast pace of at least 2 kilometers each year, says Ian Joughin, a glaciologist at the University of Washington in Seattle. About three-quarters of the temblors originated beneath the island's largest glaciers: Kangerdlugssuac, Jakobshavn Isbrae, and Helheim. Recent field studies have shown that all three glaciers have thinned and accelerated during the past 2 years (SN: 12/17/05, p. 387). Greenland's glacial gla·cial adj. 1. a. Of, relating to, or derived from a glacier. b. Suggesting the extreme slowness of a glacier: Work proceeded at a glacial pace. 2. a. quakes are five times as common in the summer as they are in winter, which hints that melting promotes the events. Before 2003, the island never suffered more than 15 such earthquakes per year. Since then, the temblors have steadily become more frequent. Between January and October 2005, more than 30 glacial quakes occurred in Greenland, Ekstrom reports in the March 24 Science. |
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